Scientific Writing, HRP 214 Weekly Quiz. A. It was a secret among friends. B. It was a secret between friends

Scientific Writing, HRP 214Weekly Quiz


A. It was a secret among friends.

B. It was a secret between friends.


A. A. It was a secret It was a secret amongamong friends. friends.

B. It was a secret between friends.


A. The close friendship that existed between them was quickly dissolved.

B. The close friendship that existed among them was quickly dissolved.


A. A. The close friendship that existed The close friendship that existed betweenbetween them was quickly dissolved.them was quickly dissolved.

B. The close friendship that existed among them was quickly dissolved.

Scientific Writing, HRP 214 Weekly Quiz

A. She eluded to the fight that occurred earlier.

B. She alluded to the the fight that occurred earlier.


A. She eluded to the fight that occurred earlier.

B. B. She She alludedalluded to the the fight that occurred to the the fight that occurred earlier.earlier.


A. She eluded the fight.

B. She alluded the fight.


A. A. She She eludedeluded the fight. the fight.

B. She alluded the fight.


A. She lies out in the sun.

B. She lays out in the sun.


A. She A. She lieslies out in the sun. out in the sun.

B. She lays out in the sun.


A. She is lying out in the sun.

B. She is laying out in the sun.


A. She A. She is lyingis lying out in the sun. out in the sun.

B. She is laying out in the sun.


A. She laid out in the sun yesterday.

B. She lay out in the sun yesterday.


A. She laid out in the sun yesterday.

B. She B. She laylay out in the sun yesterday. out in the sun yesterday.


A. She had laid out in the sun too much as a kid.

B. She had lain out in the sun too much as a kid.


A. She had laid out in the sun too much as a kid.

B. She B. She had lainhad lain out in the sun too much out in the sun too much as a kid.as a kid.


A. She lies the book on the table.

B. She lays the book on the table.


A. She lies the book on the table.

B. She B. She layslays the book on the table. the book on the table.


A. She is lying the book on the table.

B. She is laying the book on the table.


A. She is lying the book on the table.

B. She B. She is layingis laying the book on the table. the book on the table.


A. She laid the book on the table this morning.

B. She lay the book on the table this morning.


A. She A. She laidlaid the book on the table this the book on the table this morning.morning.

B. She lay the book on the table this morning.


A. She had lain the book on the table.

B. She had laid the book on the table.


A. She had lain the book on the table.

B. She B. She had laidhad laid the book on the table. the book on the table.


A. Now I lay down to sleep.

B. Now I lie down to sleep.


A. Now I lay down to sleep.

B. Now I B. Now I lielie down to sleep. down to sleep.


A. Now I lay me down to sleep.

B. Now I lie me down to sleep.


A. Now I laylay me down to sleep.

B. Now I lie me down to sleep.


A. She commented on the clearly defined mutant traits.

B. She commented on the clearly-defined mutant traits.


A. She commented on the A. She commented on the clearly definedclearly defined mutant traits.mutant traits.

B. She commented on the clearly-defined mutant traits.


A. I am disinterested in your results.

B. I am uninterested in your results.


A. I am disinterested in your results.

B. I am B. I am uninteresteduninterested in your results. in your results.


A. We think you should look into an alternative career path, i.e. get a new job.

B. We think you should look into an alternative career path, e.g. get a new job.


A. We think you should look into an A. We think you should look into an alternative career path, alternative career path, i.e.i.e. get a new get a new job.job.

B. We think you should look into an alternative career path, e.g. get a new job.


A. They prefer mixed drinks, e.g. gin and tonic or martinis.

B. They prefer mixed drinks, i.e. gin and tonic or martinis.


A. They prefer mixed drinks, A. They prefer mixed drinks, e.g.e.g. gin and gin and tonic or martinis.tonic or martinis.

B. They prefer mixed drinks, i.e. gin and tonic or martinis.


A. She served as a disinterested party in the dispute.

B. She served as an uninterested party in the dispute.


A.A. She served as a She served as a disinteresteddisinterested party in party in the dispute.the dispute.

B. She served as an uninterested party in the dispute.


A. You should eat more sweets, e.g. chocolate.

B. You should eat more sweets, i.e. chocolate.


A. You should eat more sweets, e.g.e.g. chocolate.

B. You should eat more sweets, i.e. chocolate.


A. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared to non-injured runners.

B. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared with non-injured runners.


A. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared to non-injured runners.

B. Runners who develop overuse running-related injuries have lower intakes of several key nutrients compared with non-injured runners.


A. Over half the runners sustained an injury during the year.

B. More than half the runners sustained an injury during the year.


A. Over half the runners sustained an injury during the year.

B. More than half the runners sustained an injury during the year.

Scientific Writing, HRP 214

Lecture 7:

The Abstract, Introduction, and Discussion

Scientific Writing, HRP 214Abstracts

Abstracts (ab=out, trahere=pull; “to pull out”)

Overview of the main story Gives highlights from each section of the paper Limited length (100-300 words, typically)

Stands on its own Used, with title, for electronic search engines Most often, the only part people read


Gives:1. Background2. Question asked

“We asked whether,” “We hypothesized that,”…etc.

3. Experiment(s) done Material studied (molecule, cell line, tissue, organ) or the animal or human population

studied The experimental approach or study design and the independent and dependent variables

4. Results found Key results found Minimal raw data (prefer summaries)

5. The answer to the question asked6. Implication, speculation, or recommendation


Abstracts may be structured (with subheadings) or free-form.


Structured example: (The Lancet, 2006 Feb 11;367(9509):475-81.) Development of adenoviral-vector-based pandemic influenza vaccine against antigenically distinct human H5N1 strains in mice. Hoelscher MA, Garg S, Bangari DS, Belser JA, Lu X, Stephenson I, Bright RA, Katz JM, Mittal SK, Sambhara S.


INTRODUCTION: Avian H5N1 influenza viruses currently circulating in southeast Asia could potentially cause the next pandemic. However, currently licensed human vaccines are subtype-specific and do not protect against these H5N1 viruses. We aimed to develop an influenza vaccine and assessed its immunogenicity and efficacy to confer protection in BALB/c mice.

METHODS: We developed an egg-independent strategy to combat the avian influenza virus, because the virus is highly lethal to chickens and the maintenance of a constant supply of embryonated eggs would be difficult in a pandemic. We used a replication-incompetent, human adenoviral-vector-based, haemagglutinin subtype 5 influenza vaccine (HAd-H5HA), which induces both humoral and cell-mediated immune responses against avian H5N1 influenza viruses isolated from people.

Background

Experiments done

Questionasked


FINDINGS: Immunisation of mice with HAd-H5HA provided effective protection from H5N1 disease, death, and primary viral replication (p<0.0001) against antigenically distinct strains of H5N1 influenza viruses. Unlike the recombinant H5HA vaccine, which is based on a traditional subunit vaccine approach, HAd-H5HA vaccine induced a three-fold to eight-fold increase in HA-518-epitope-specific interferon-gamma-secreting CD8 T cells (p=0.01).

INTERPRETATION: Our findings highlight the potential of an Ad-vector-based delivery system, which is both egg-independent and adjuvant-independent and offers stockpiling options for the development of a pandemic influenza vaccine.

Results found

Answer to the question asked

Wider implication


Structured example 2:

N Engl J Med. 2006 Feb 16;354(7):684-96.

Calcium plus vitamin D supplementation and the risk of colorectal cancer. Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O'Sullivan MJ, Margolis KL, Ockene JK, Phillips L, Pottern L, Prentice RL, Robbins J, Rohan TE, Sarto GE, Sharma S, Stefanick ML, Van Horn L, Wallace RB, Whitlock E, Bassford T, Beresford SA, Black HR, Bonds DE, Brzyski RG, Caan B, Chlebowski RT, Cochrane B, Garland C, Gass M, Hays J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Jackson RD, Johnson KC, Judd H, Kooperberg CL, Kuller LH, LaCroix AZ, Lane DS, Langer RD, Lasser NL, Lewis CE, Limacher MC, Manson JE; Women's Health Initiative Investigators.


ABSTRACT BACKGROUND: Higher intake of calcium and vitamin D has been associated with a

reduced risk of colorectal cancer in epidemiologic studies and polyp recurrence in polyp-prevention trials. However, randomized-trial evidence that calcium with vitamin D supplementation is beneficial in the primary prevention of colorectal cancer is lacking.

METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 36,282 postmenopausal women from 40 Women's Health Initiative centers: 18,176 women received 500 mg of elemental calcium as calcium carbonate with 200 IU of vitamin D3 twice daily (1000 mg of elemental calcium and 400 IU of vitamin D3) and 18,106 received a matching placebo for an average of 7.0 years. The incidence of pathologically confirmed colorectal cancer was the designated secondary outcome. Baseline levels of serum 25-hydroxyvitamin D were assessed in a nested case-control study.

Background

Literature gap.

Study Design


RESULTS: The incidence of invasive colorectal cancer did not differ significantly between women assigned to calcium plus vitamin D supplementation and those assigned to placebo (168 and 154 cases; hazard ratio, 1.08; 95 percent confidence interval, 0.86 to 1.34; P=0.51), and the tumor characteristics were similar in the two groups. The frequency of colorectal-cancer screening and abdominal symptoms was similar in the two groups. There were no significant treatment interactions with baseline characteristics.

CONCLUSIONS: Daily supplementation of calcium with vitamin D for seven years had no effect on the incidence of colorectal cancer among postmenopausal women. The long latency associated with the development of colorectal cancer, along with the seven-year duration of the trial, may have contributed to this null finding. Ongoing follow-up will assess the longer-term effect of this intervention.

Results found

Answer to the question asked

The caveats.


Even more subheadings…

Effect of Rimonabant, a Cannabinoid-1 Receptor Blocker, on Weight and Cardiometabolic Risk Factors in Overweight or Obese Patients RIO-North America: A Randomized Controlled Trial

F. Xavier Pi-Sunyer, MD; Louis J. Aronne, MD; Hassan M. Heshmati, MD; Jeanne Devin, MS; Julio Rosenstock, MD; for the RIO-North America Study Group

JAMA. 2006;295:761-775.


Context: Rimonabant, a selective cannabinoid-1 receptor blocker, may reduce body weight and improve cardiometabolic risk factors in patients who are overweight or obese.

Objective: To compare the efficacy and safety of rimonabant with placebo each in conjunction with diet and exercise for sustained changes in weight and cardiometabolic risk factors over 2 years.

Design, Setting, and Participants: Randomized, double-blind, placebo-controlled trial of 3045 obese (body mass index 30) or overweight (body mass index >27 and treated or untreated hypertension or dyslipidemia) adult patients at 64 US and 8 Canadian clinical research centers from August 2001 to April 2004.

Intervention: After a 4-week single-blind placebo plus diet (600 kcal/d deficit) run-in period, patients were randomized to receive placebo, 5 mg/d of rimonabant, or 20 mg/d of rimonabant for 1 year. Rimonabant-treated patients were rerandomized to receive placebo or continued to receive the same rimonabant dose while the placebo group continued to receive placebo during year 2.


Results: At year 1, the completion rate was 309 (51%) patients in the placebo group, 620 (51%) patients in the 5 mg of rimonabant group, and 673 (55%) patients in the 20 mg of rimonabant group. Compared with the placebo group, the 20 mg of rimonabant group produced greater mean (SEM) reductions in weight (–6.3 [0.2] kg vs –1.6 [0.2] kg; P<.001), waist circumference (–6.1 [0.2] cm vs –2.5 [0.3] cm; P<.001), and level of triglycerides (percentage change, –5.3 [1.2] vs 7.9 [2.0]; P<.001) and a greater increase in level of high-density lipoprotein cholesterol (percentage change, 12.6 [0.5] vs 5.4 [0.7]; P<.001). Patients who were switched from the 20 mg of rimonabant group to the placebo group during year 2 experienced weight regain while those who continued to receive 20 mg of rimonabant maintained their weight loss and favorable changes in cardiometabolic risk factors. Use of different imputation methods to account for the high rate of dropouts in all 3 groups yielded similar results. Rimonabant was generally well tolerated; the most common drug-related adverse event was nausea (11.2% for the 20 mg of rimonabant group vs 5.8% for the placebo group).


Conclusions: In this multicenter trial, treatment with 20 mg/d of rimonabant plus diet for 2 years promoted modest but sustained reductions in weight and waist circumference and favorable changes in cardiometabolic risk factors. However, the trial was limited by a high drop-out rate and longer-term effects of the drug require further study.


Science. 2006 Feb 17;311(5763):1020-2. Causal reasoning in rats. Blaisdell AP, Sawa K, Leising KJ, Waldmann MR.

Empirical research with nonhuman primates appears to support the view that causal reasoning is a key cognitive faculty that divides humans from animals. The claim is that animals approximate causal learning using associative processes. The present results cast doubt on that conclusion. Rats made causal inferences in a basic task that taps into core features of causal reasoning without requiring complex physical knowledge. They derived predictions of the outcomes of interventions after passive observational learning of different kinds of causal models. These competencies cannot be explained by current associative theories but are consistent with causal Bayes net theories.

Scientific Writing, HRP 214Introduction and Background

Introduction and Background Section


The Literature Search Utilize online databases, such as MEDLINE, PubMed,

and Ovid. Have a search strategy. Have an organizational system!


The Literature Review Summarize the current state of knowledge in the area of investigation. You may have to return to the literature once your results are in hand.

Assume your reader is knowledgeable about the field. Do not provide an exhaustive historical review. Avoid nonessential details. Summarize previous results and conclusions, but do not give the methods that

generated these findings unless they are relevant to your research question (i.e., your experiment addresses a specific methodologic limitation of previous experiments)

Refer the reader to general surveys or reviews of the topic if available. Cite references that reflect the key work that led to your research question. Limit the number of references.


In writing the literature review, summarize rather than listing every possible reference and example.


Introduction and Background

1. What’s known2. What’s unknown limitations and gaps in previous studies

3. Your burning question4. Your experimental approach5. Why your experimental approach is new and different

and important

Critical literature review

From: Essentials of Writing Biomedical Research Papers by Mimi Zeiger

Scientific Writing, HRP 214IntroductionTell a story: Write it in plain English, not tech-speak. Take the reader step by step from what is known to

what is unknown. End with your specific question.(KnownUnknownQuestion)

Emphasize what is new and important about your work.

Do not state the answer to the research question. Do not include results or implications.

Introduction

Overweight, Obesity, and Mortality from Cancer in a Prospectively Studied Cohort of U.S. AdultsEugenia E. Calle, Ph.D., Carmen Rodriguez, M.D., M.P.H., Kimberly Walker-Thurmond, B.A., and Michael J. Thun, M.D.

The relations between excess body weight and mortality, not only from all causes but also from cardiovascular disease, are well established.1,2,3,4,5,6 Although we have known for some time that excess weight is also an important factor in death from cancer,7 our knowledge of the magnitude of the relation, both for all cancers and for cancers at individual sites, and the public health effect of excess weight in terms of total mortality from cancer is limited. Previous studies have consistently shown associations between adiposity and increased risk of cancers of the endometrium, kidney, gallbladder (in women), breast (in postmenopausal women), and colon (particularly in men).8,9,10,11,12 Adenocarcinoma of the esophagus has been linked to obesity.11,13,14 Data on cancers of the pancreas, prostate, liver, cervix, and ovary and on hematopoietic cancers are scarce or inconsistent.7,8,9,10,11,15,16,17 The lack of consistency may be attributable to the limited number of studies (especially those with prospective cohorts), the limited range and variable categorization of overweight and obesity among studies, bias introduced by reverse causality with respect to smoking-related cancers, and possibly real differences between the effects of overweight and obesity on the incidence

of cancer and on the rates of death from some cancers.18,19

We conducted a prospective investigation in a large cohort of U.S. men and women to determine the relations between body-mass index (the weight in kilograms divided by the square of the height in meters) and the risk of death from cancer at specific sites. This cohort has been used previously to examine the association of body-mass index and death from any cause.5

What’s known What’s unknownWhat’s known What’s unknown

Gaps/limitations ofprevious studies

“This study willanswer thequestion withbetter methods.”

Scientific Writing, HRP 214Introduction

Exogenous estrogens prevent or substantially retard the decrease in bone mineral density (BMD) that accompanies menopause [1]. However, it is unclear whether exogenous estrogens, administered as oral contraceptives (OCs), can modify premenopausal BMD. Several studies suggest that exposure to OCs during the premenopausal years has a favorable effect on BMD [2-10], whereas other studies show no effect [11-18].

Past studies of the relationship between OC use and BMD have several limitations. Studies have focused primarily on crude measures of OC use, such as current, past and never. These categories combine diverse types of OC use and may reduce the power to detect an effect. Many studies also failed to take into account lifestyle characteristics of study participants. Finally, few studies have considered an effect of OCs on BMD in women of races other than white.

The aim of this study was to evaluate the associations of OCs with spine, hip and whole body BMD in black and white premenopausal women. Our primary hypothesis was that there would be an association between cumulative exposure to estrogen from OCs and BMD.

What’s known

What’s unknown/the research question

The lit.review

Gaps inpreviousresearch

This study

Neurohumoral Features of Myocardial Stunning Due to Sudden Emotional StressIlan S. Wittstein, M.D., David R. Thiemann, M.D., Joao A.C. Lima, M.D., Kenneth L. Baughman, M.D., Steven P. Schulman, M.D., Gary Gerstenblith, M.D., Katherine C. Wu, M.D., Jeffrey J. Rade, M.D., Trinity J. Bivalacqua, M.D., Ph.D., and Hunter C. Champion, M.D., Ph.D. T

New Engl J Med Volume 352:539-548; Feb 10, 2005.


The potentially lethal consequences of emotional stress are

deeply rooted in folk wisdom, as reflected by phrases such as "scared to death" and "a broken heart." In the past decade, cardiac contractile abnormalities and heart failure have been reported after acute emotional stress,1,2,3,4,5,6 but the mechanism remains unknown. We evaluated 19 patients with "stress cardiomyopathy," a syndrome of profound myocardial stunning precipitated by acute emotional stress, in an effort to identify the clinical features that distinguish this syndrome from acute myocardial infarction and the cause of transient stress-induced myocardial dysfunction.

Background/relevanceThe lit.

review

What’s unknown

This study


Introduction: systematic review

Effectiveness of speed cameras in preventing road traffic collisions and related casualties: systematic review Paul Pilkington, lecturer in public health1, Sanjay Kinra, lecturer in epidemiology and public health medicine2 1 University of the West of England, Faculty of Health and Social Care, Bristol BS16 1DD, 2 Department of Social Medicine, University of

Bristol, Bristol . BMJ Feb. 10, 2005

Road traffic collisions are an important cause of death and disability worldwide. Every year around the world 1.2 million people are killed and up to 50 million are injured or disabled as a result of road traffic collisions.1 Morbidity from road traffic collisions is expected to increase in future years, and it is estimated that road traffic collisions will move from ninth to third place in the global burden of disease ranking, as measured in disability adjusted life years.2 3

Measures to reduce traffic speed are considered essential to reducing casualties on the road.1 4 5 Speed cameras are increasingly used to help to reduce traffic speeds in the belief that this will reduce road traffic collisions and casualties, and an expansion in the use of speed cameras is under way in many countries, most notably the United Kingdom.6 The use of speed cameras is controversial, however. Vociferous opponents, including some motoring associated organisations, oppose their use, and cameras are often criticised in the media.7-9 The lack of readily available evidence of the effectiveness of cameras has made it difficult for road safety and health professionals to engage in an informed debate about the effectiveness of speed cameras.

A previous small non-systematic review of six studies found a 17% reduction in collisions after introduction of speed cameras.10 Non-systematic reviews can, however, be limited by bias. We aimed, therefore, to systematically assess the evidence for the effectiveness of speed cameras in reducing road traffic collisions and related casualties.

What we did to answer this question better.

Statement of problem. What’s known.

What’s unknown/controversial.

Limitations of previous research.

Introduction: cohort study

Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study M Á Martínez-González, professor of epidemiology and chair,1 C de la Fuente-Arrillaga, research assistant,1 J M Nunez-Cordoba, research fellow,1,2 F J Basterra-Gortari, research fellow,1,3 J J Beunza, assistant professor,1 Z Vazquez, research assistant,1 S Benito, research assistant,1 A Tortosa, research fellow,1 and M Bes-Rastrollo, assistant professor1 BMJ June 14, 2008

Diabetes mellitus is an increasingly important global public health problem that threatens to reach pandemic levels by 2030.1 2 As some randomised trials have consistently shown, increased physical activity and weight loss are efficient approaches for the control and prevention of type 2 diabetes.3 4 Diet has also long been believed to be an important risk factor for diabetes. Many studies have shown that the Mediterranean food pattern has a role in prevention of cardiovascular disease.5 6 7 8 9 The similarity of some risk factors and some empirical and mechanistic evidence suggest that the Mediterranean diet can also protect against diabetes. The major protective characteristics include a high intake of fibre, a high intake of vegetable fat, a low intake of trans fatty acids, and a moderate intake of alcohol.4 10 11 Moreover, a particular feature of the diet is the abundant use of virgin olive oil for cooking, frying, spreading on bread, or dressing salads.12 This leads to a high ratio of monounsaturated fatty acids to saturated fatty acids. This ratio can be used to score adherence to a Mediterranean diet8 as the traditional diet. Despite having a relatively high total fat content, this food pattern is rich in monounsaturated fatty acids (from olive oil) and poor in saturated fatty acids. Diets rich in monounsaturated fatty acids improve lipid profiles and glycaemic control in people with diabetes, suggesting that a high intake improves insulin sensitivity.13 14 15 16 Together these associations suggest the hypothesis that following an overall pattern of Mediterranean diet can protect against diabetes. In addition to having a long tradition of use without evidence of harm, a Mediterranean diet is highly palatable, and people are likely to comply with it.17

Background on the Mediterranean diet.

What is known about Mediterranean diet and diabetes.

Few prospective studies have evaluated the specific role of the Mediterranean diet on the risk of developing diabetes in initially healthy Mediterranean populations. A prospective follow-up study recently reported an inverse association between adherence to the diet and the incidence of diabetes.18 All members of that study, however, had survived a previous myocardial infarction and the tool to assess dietary habits had inherent limitations because it included only a short list of items, and the authors did not attempt to measure the entire diet.

We evaluated the association between adherence to a Mediterranean diet and the incidence of diabetes using a full validated food frequency questionnaire to measure the entire diet.

What’s unknown/gaps in literature.

What we did to answer this question better.


Introduction and Background

1. What’s known2. What’s unknown limitations and gaps in previous studies

3. Your burning question4. Your experimental approach5. Why your experimental approach is new and different

and important

Critical literature review

From: Essentials of Writing Biomedical Research Papers by Mimi Zeiger

Scientific Writing, HRP 214IntroductionTell a story: Write it in plain English, not tech-speak. Take the reader step by step from what is known to

what is unknown. End with your specific question.(KnownUnknownQuestion)

Emphasize what is new and important about your work.

Do not state the answer to the research question. Do not include results or implications.

Scientific Writing, HRP 214THE DISCUSSION

The Discussion is the section that…

• Gives you the most freedom • Gives you the most chance to put good

writing on display• Is the most challenging to write

Scientific Writing, HRP 214The Discussion

Follow your rules for good writing!


The purpose of the discussion:

• Answer the question posed in the Introduction• Support your conclusion with details (yours, others)• Defend your conclusion (acknowledge limits)• Highlight the broader implications of the work

i.e., What do my results mean and why should anyone care?

Framework of the DiscussionQUESTION TO ADDRESS

CONTENT

What’s the central finding?

Restate the finding.Place in the context of other work.Clearly state what’s new.

Could it be wrong? Identify and deal with threats to validity. Consider alternative explanations for your findings given the study design (for clinical or epidemiologic studies):

BEFORE/AFTER OBSERVATIONAL RANDOMIZED TRIAL

Temporal trendRegression to the meanSelection bias

Loss to follow-upLow response rateRecall biasUnmeasured confounding

Inadequate blindingAscertainment biasLoss to follow-up

What does it mean? Put your work in perspective. Assess its generalizability, and speculate about its implications.Suggest mechanisms. Specify what you think should happen next.

Table 2, Adapted From: Welch HG. Preparing Manuscripts for Submission to Medical Journals: The Paper Trail. Effective Clinical Practice. 1999; 2: 131-137.


The introduction moves from general to specific.

The discussion moves from specific to general.


Elements of the typical discussion section…

1. Key finding (answer to the question(s) asked in Intro.)• Supporting explanation, details (lines of evidence)• Possible mechanisms or pathways• Is this finding novel?

2. Key secondary findings3. Context

• Compare your results with other people’s results• Compare your results with existing paradigms• Explain unexpected or surprising findings

4. Strengths and limitations5. What’s next

• Recommended confirmatory studies (“needs to be confirmed”)• Unanswered questions• Future directions

6. The “so what?”: implicate, speculate, recommend• Clinical implications of basic science findings

7. Strong conclusion (kicker!)

EXAMPLE: Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med 2003;348:2074-2081.

INTRODUCTIONThe differences in health benefits between a carbohydrate-restricted

diet and a calorie- and fat-restricted diet are of considerable public interest. However, there is concern that a carbohydrate-restricted diet will adversely affect serum lipid concentrations.1 Previous studies demonstrating that healthy volunteers following a low-carbohydrate

diet can lose weight have involved few subjects, and few used a comparison group that followed consensus guidelines for weight loss.2,

3 The reported effects of a carbohydrate-restricted diet on risk factors for atherosclerosis have varied.2,3,4 We performed a study designed to test the hypothesis that severely obese subjects with a high prevalence of diabetes or the metabolic syndrome [a] would have a greater weight loss, [b] without detrimental effects on risk factors for atherosclerosis, while on a carbohydrate-restricted

(low-carbohydrate) diet than on a calorie- and fat-restricted (low-fat) diet.


1. We found that severely obese subjects with a high prevalence of diabetes and the metabolic syndrome lost more weight in a six-month period on a carbohydrate-restricted diet than on a fat- and calorie-restricted diet. [answer to a] The greater weight loss in the low-carbohydrate group suggests a greater reduction in overall caloric intake, rather than a direct effect of macronutrient composition. [mechanisms] However, the explanation for this difference is not clear. Subjects in this group may have experienced greater satiety on a diet with liberal proportions of protein and fat. However, other potential explanations include the simplicity of the diet and improved compliance related to the novelty of the diet. [possible mechanisms/unanswered questions]


2. Subjects in the low-carbohydrate group had greater decreases in triglyceride levels than did subjects in the low-fat group; nondiabetic subjects on the low-carbohydrate diet had greater

increases in insulin sensitivity, and subjects with diabetes on this diet had a greater improvement in glycemic control. No adverse effects on other serum lipid levels were observed.

[answer to b] Most studies suggest that lowering triglyceride levels has an overall cardiovascular benefit.14,15,16 Insulin resistance promotes such atherosclerotic processes as inflammation,17 decreased size of low-density lipoprotein particles,18 and endothelial dysfunction.19 Impaired glycemic control in subjects with other features of the metabolic syndrome markedly increases the risk of coronary artery disease.20 As expected, we found that the amount of weight lost had a significant effect on the degree of improvement in these metabolic factors.

[comparison to previous studies and paradigms] However, even after

adjustment for the differences in weight loss between the groups, assignment to the low-carbohydrate diet predicted greater improvements in triglyceride levels and insulin sensitivity.

[unexpected] Subjects who lost more than 5 percent of their base-line weight on a carbohydrate-restricted diet had greater decreases in triglyceride levels than those who lost a

similar amount of weight while following a calorie- and fat-restricted diet. [supporting details]


3. There was a consistent trend across weight-loss strata toward a greater increase in insulin sensitivity in the low-carbohydrate group, although these changes were small and were not significant within each stratum. [supporting details: dose/response] Although greater weight loss could not entirely account for the greater decrease in triglyceride levels and increase in insulin sensitivity in the low-carbohydrate group, we cannot definitively conclude that carbohydrate restriction alone accounted for this independent effect. [mechanisms] Other uncontrolled

variables, such as the types of carbohydrates selected (e.g., the proportion of complex carbohydrates or the ratio of carbohydrate to fiber), or other unknown variables may have contributed to this effect. In addition, more precise measurements of insulin sensitivity than we used would be needed to confirm this effect of a carbohydrate-restricted diet.

[limitations/future studies]


4. Many of our subjects were taking lipid-lowering medications and hypoglycemic agents. Although enrolling these subjects introduced confounding variables, it allowed the inclusion of subjects with the obesity-related medical disorders typically encountered in clinical practice. Analyses from which these subjects were excluded still revealed greater improvements in insulin sensitivity and triglyceride levels on a carbohydrate-restricted diet than on a fat- and calorie-restricted diet. [limitations and how they were addressed]


5. Our study included a high proportion of black subjects, a group

previously underrepresented in lifestyle-modification studies.

[strength] As compared with the white subjects, the black subjects had a smaller overall weight loss. Future studies should explore whether greater weight loss in this population can be achieved by more effective incorporation of culturally sensitive dietary counseling. [future directions]

6. The high dropout rate in our study occurred very early and affected our findings. The very early dropout of these subjects may indicate that attrition most closely reflected base-line motivation to lose weight, rather than a response to the dietary intervention itself. [limitation]


7. Taken together, our findings demonstrate that severely obese subjects with a high prevalence of diabetes and the metabolic syndrome lost more weight during six months on a carbohydrate-restricted diet than on a calorie- and fat-restricted diet. The carbohydrate-restricted diet led to greater improvements in insulin sensitivity that were independent of weight loss and a greater reduction in triglyceride levels in subjects who lost more than 5 percent of their base-line weight. [conclusion; restate answers to a and b] These findings must be interpreted with caution, however, since the magnitude of the overall weight loss relative to our subjects' severe obesity was small, and it is unclear whether these benefits of a carbohydrate-restricted diet extend beyond six months. Furthermore, the high dropout rate and the small overall weight loss demonstrate that dietary adherence was relatively low in both diet groups. [big picture] This study proves a principle and does not provide clinical guidance; given the known benefits of fat restriction, future studies evaluating long-term cardiovascular outcomes are needed before a carbohydrate-restricted diet can be endorsed. [take-home message]


Things to avoid in the discussion:• Do not simply repeat what is in the Results• Do not try to explain every minor flaw• Do not attempt to explain away every

unexpected result• Do not exaggerate or make extravagant

claims• Don’t hedge

What NOT to do!

Don’t start your discussion like this!!

Discussion This meta-analysis is subject to a number of

limitations. The estimates of risk for melanoma subsequent to using sunlamps/sunbeds are based on published data in a series of 10 articles over a period of 20 years. A pooled analysis of original observations taken in the 10 studies would have provided a more powerful approach …

Scientific Writing, HRP 214The Discussion: verb tense

Verb Tenses (active!):Past, when referring to study details, results, analyses, and background

research:• We found that • They lost more weight than• Subjects may have experienced• Miller et al. found

Present, when talking about what the data suggest … The greater weight loss suggests The explanation for this difference is not clear. Potential explanations include

EXAMPLE 2: Low-Fat Dietary Pattern and Risk of Colorectal Cancer The Women's Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006;295:643-654.

INTRODUCTION The Women's Health Initiative (WHI) Dietary Modification Trial is a randomized controlled trial designed in

1991-1992 to test whether a low-fat eating pattern with increased fruits, vegetables, and grains reduces

the risk of breast cancer, colorectal cancer, or, secondarily, coronary heart disease in postmenopausal

women. At that time, international comparisons suggested that countries with 50% lower fat intake than

the US population had approximately one third the risk of colorectal cancer.1-2 Migration studies

supported this hypothesis. Women migrating from countries with low fat consumption to countries with

high fat consumption experienced the higher colorectal cancer rates of their new country.3-4 Fairly

consistent evidence existed for an effect of dietary fat, vegetables and fruits, and grains on colorectal

cancer risk from within-country observational studies,2, 5-8 although the protective effect of lower fat

intake was no longer clear after adjusting for energy intake.2, 9 The WHI Dietary Modification

Trial is the first randomized trial to directly address the health effects of a low-

fat eating pattern in predominantly healthy postmenopausal women from

diverse racial/ethnic, geographic, and socioeconomic backgrounds. This article

reports the principal results for colorectal cancer. [the question]


1. An intervention aimed toward a low-fat eating pattern did not reduce colorectal cancer risk in postmenopausal women. [answer to the question asked] Despite a significant change in fat intake and increases in vegetable, fruit, and grain consumption, the intervention hazard ratio is in the direction of an increased risk. [supporting evidence from this trial] There were no substantial differences in tumor characteristics or in rates of bowel screening between groups. [supporting evidence] Although self-reported incidence of colorectal

polyps or adenomas was lower in the intervention group, no evidence of a trend toward lower colorectal cancer risk with time in the intervention group was observed over the mean 8.1-year study period.


2. These findings are consistent with the findings from the Polyp

Prevention Trial,31 a secondary prevention trial of polyp recurrence, which had a similar goal for fat, fruit, and vegetable intake but also included a goal of 18 g/1000 kcal of dietary fiber.32 The Polyp Prevention Trial observed no effect on polyp recurrence in the 2079 participants followed up for 4 years.32 A small trial in Toronto, Ontario, of high fiber and low fat showed

no effect on recurrence of neoplastic polyps, but, within an

intensive counseling subgroup, concentrations of fecal bile acids appeared to be reduced.33 A small factorial trial in Australia of a low-fat intervention, -carotene supplementation, or wheat bran supplementation found no reduction in recurrence rates of adenomas but suggested that the combination of low fat and

wheat bran reduced the transition from smaller to larger adenomas.34 [supporting evidence: other TRIALS]


3. Since the WHI Dietary Modification Trial was designed, the hypothesized relationship between dietary fat and risk of colorectal cancer has been questioned.35 More recently, higher red meat consumption has been associated with increased colorectal cancer risk,23, 36-39 particularly in the distal colon.23 The putative mechanism may be related to heme, the iron carrier of red meat, rather than to its fat content.23 In the WHI, the dietary intervention reduced red meat consumption (Table 2), with no apparent overall benefit on colorectal cancer risk but, perhaps, some shift in

risk in distal vs proximal colon cancers.

[consistency with the latest paradigm] [mechanisms: is red meat more important than fat?]

Scientific Writing, HRP 214The Discussion 4. Mixed support exists for an influence of vegetables and fruits on colorectal cancer risk.37, 40-42 Some of the antioxidants they contain have not proved efficacious in reducing colorectal adenomas or preventing incident colorectal cancer in randomized trials.43-45 Regular consumption of alcohol has been associated with elevated risk of colorectal cancer in some prospective studies, particularly among persons with low folate status.46 This pattern was not found in the comparison group of this study. Observations in East Africa by Burkitt47 led to the hypothesis that very high fiber reduces colorectal cancer risk. This has mixed support from observational studies48-50 and polyp and adenoma recurrence trials.31, 33-34,51-52 A European trial found an adverse effect of soluble fiber on colorectal adenoma recurrence,51 while an Arizona trial found no effect of wheat bran supplement on colorectal adenoma recurrence.52 Our study is consistent with lack of association in that women in the intervention group modestly increased their fiber (Table 2) with no apparent benefit

over 8.1 years of follow-up.

[existing paradigms: does fiber matter?]


5. The observed interactions between the intervention and baseline aspirin use, and between intervention and use of combined hormone therapy, are consistent with synergistic effects of a low-fat dietary pattern and these potentially protective agents. However, given the large number of interactions tested, these findings could also have occurred by chance.

[Could the null finding be wrong? Maybe low-fat diet matters for some groups]


6. From National Health and Nutrition Examination Survey (NHANES) data, in 1977, women reported consuming 40.5% of their energy from fat, while in 1987, the average was only 35.9%,54 and in 2000, the average was 33% (NHANES 1999-2000). Organizations including the National Cancer Institute, American Cancer Society, and Institute for Cancer Prevention have recommended both lower fat intake and increased vegetable and fruit use.55-56

7. One explanation for a lack of intervention effect on colorectal cancer could be that the intervention did not achieve a large enough difference between the intervention and comparison groups. Although the changes achieved were substantial, and likely as large as could be achieved in a trial of free-living individuals, they fell short of the original design assumptions based on the Women's Health Trial studies.27 Using food frequency data, the WHI intervention on average achieved only about 70% of the designed reduction in fat. If design assumptions are revised to take into account this departure from goal, the predicted HR would have been 0.86, an effect size excluded by these results. The power to detect this effect size under the observed comparison group incidence rate and the achieved adherence is approximately 40%. [Could the null finding be wrong? Alternative explanations to no association]


8. Whether greater adherence, intervention of longer duration,

or initiation of change at an earlier age would influence colorectal cancer risk remain unanswered questions. The self-reported first occurrence of polyps or adenomas was lower in dietary intervention women, suggesting that longer follow-up (currently planned) may reveal delayed benefit in favor of the intervention. Yet no time trends regarding colorectal cancer risk over 8 years of follow-up have been seen. To the extent that the WHI Dietary Modification Trial intervention addressed the recommendations from national organizations, the current results suggest that changing dietary patterns to meet these recommendations in mid to late life will have limited or no benefit in preventing colorectal cancers in postmenopausal women. [Defending their results]


9. The strengths of this study are its randomized design, long-term follow-up, large numbers of participants, diversity of race/ethnicity and socioeconomic status, and high retention rate. The limitations of this study include not attaining intervention goals as designed for reducing fat intake or achieving large separation from the comparison group in increased fruit, vegetable, or grain intake. Thus the potential intervention effect of the WHI low-fat dietary

pattern may be underestimated. Furthermore, there was no study-specified colonoscopy, nor was there systematic screening for adenomatous polyps; hence, the incidence of both colorectal cancer and polyps or adenomas would be underestimated. [Strengths and limitations]


10. In conclusion, there is no evidence that a low-fat dietary pattern intervention reduces colorectal cancer risk over an average of 8.1 years of follow-up. [Restatement of findings] Evidence from this study, along with that from polyp prevention trials, strongly suggests that lowering dietary fat intake and increasing fruit, vegetable, and fiber intake in mid to late life cannot be expected to reduce the

risk of colorectal cancer in this length of time. [Take-home message]

EXAMPLE: Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study

BMJ June 2008 END OF INTRODUCTION:

We evaluated the association between adherence to a Mediterranean diet and the incidence of diabetes using a full validated food frequency questionnaire to measure the entire diet.


1. This large prospective study shows that a traditional Mediterranean food pattern is associated with a significant reduction in the risk of developing type 2 diabetes. [answer to question asked]


2. Interestingly, among participants with the highest adherence to the diet, there was a high prevalence of important risk factors for diabetes, such as older age, higher BMI, family history of diabetes, and personal history of hypertension and a higher proportion of ex-smokers. Therefore, we would have expected a higher incidence of diabetes among these participants. These higher risk participants with better adherence to the diet, however, had a lower risk of diabetes, suggesting that the diet might have a substantial potential for prevention. [ “bonus” finding/additional evidence] This finding is consistent with our previous report of an inverse

association between a Mediterranean diet and the metabolic syndrome.24 [fits with previous research] The metabolic syndrome is closely associated with a generalised metabolic disorder of insulin resistance, which is one of the underlying causes of type 2 diabetes. Therefore a high biological plausibility exists to support the causality of our findings. [biological mechanisms] In addition, a previous cohort study of survivors of myocardial infarction also reported that a higher adherence to a Mediterranean diet was associated with a reduction in the risk of type 2 diabetes,18 [fits previous research] despite use of a relatively inaccurate tool for the dietary assessment. The inverse graded dose-response pattern and the significant inverse trend that we observed also support a causal relation. [dose-response evidence]


3. Diet and disease Experimental evidence suggesting that a diet similar to the

Mediterranean diet and rich in plant based foods might protect against diabetes can also be found in the Indian diabetes prevention programme. That trial promoted a plant based diet (together with increases in physical activity) and found a significant reduction in the incidence of diabetes,28 although there are clear differences between the Mediterranean and Indian food patterns. There is an analogy between coronary heart disease and diabetes because patients with type 2 diabetes and no coronary heart disease have a risk of coronary heart disease similar to patients without diabetes but with prior coronary heart disease.29 There is evidence that a Mediterranean diet protects against coronary heart disease, and the analogy between coronary heart disease and diabetes suggests that this diet might also prevent diabetes. It has been shown to provide protection against coronary mortality8 9 30 31 and the incidence of non-fatal myocardial infarction.32 In addition, both cohort studies33 34 35 and randomised trials36 have found that adherence to a Mediterranean diet protects against mortality in patients who already have established coronary heart disease. [more supporting background evidence]


4.The potential mechanisms explaining the protective effect of a Mediterranean diet on diabetes have been reviewed elsewhere.37 38 39 40 Two trials have shown that virgin olive oil protects against insulin resistance and the metabolic syndrome.6 7 Indexes of insulin resistance were significantly improved among participants allocated to a Mediterranean diet rich in virgin olive oil. Olive oil is rich in monounsaturated fatty acids, and a diet rich in monounsaturated fatty acids is beneficial among those with diabetes and might lead to improved insulin sensitivity and better lipid profiles than diets rich in carbohydrate.13 15 39 People allocated to a Mediterranean diet secrete more glucagon-like peptide-1,16 a finding also seen in animals.14 The non-fat minor components of virgin olive oil also exert a beneficial effect on pro-inflammatory cytokines.40 41 42

Apart from olive oil, adherence to an overall Mediterranean-type food pattern is related to lower plasma concentrations of inflammatory markers and markers of endothelial dysfunction.43 44 These biomarkers are predictive of the future occurrence of type 2 diabetes.45 46 In addition, a large cross sectional study nested in the nurses’ health study found that increased adherence to a Mediterranean diet was associated with higher levels of adiponectin,47 and higher levels of adiponectin are associated with a reduced risk of diabetes.

[supporting evidence in the literature/biological mechanisms]

Scientific Writing, HRP 214The Discussion Limitations The number of new cases of diabetes was small, despite the follow-up of several thousand

people for over four years. This small number of incident cases is a major drawback and can compromise the statistical power of our study. Nevertheless, our participants had high absolute levels of consumption of the typical food items of the Mediterranean diet, even among those participants classified as poorly compliant (score <3). For example, among those in the lowest category of adherence to the diet, the estimated mean daily absolute consumption (g/day) of olive oil (12), vegetables (308), fruits (176), cereals (77), and legumes (17) can be considered as healthy for the standards of nutritional epidemiological studies. This high consumption of plant based foods in our cohort could be because our participants were from a Mediterranean country and were highly educated and health conscious. The small number of new cases observed in this study should therefore not be surprising. If the Mediterranean diet is actually protecting against diabetes, we would expecta low incidence in a young cohort (mean age is 37.8 years) with these characteristics. The low number of observed cases precluded assessment of the specific role of single dietary factors because we would have needed

…..

A potential limitation, inherent to every observational design, is the possibility of residual confounding by unmeasured or unrecorded factors. Our major confounders, however, were sex and age. Additional adjustment for other factors made only negligible changes in the estimates, suggesting that residual confounding is unlikely.in the nurses’ health study found that increased adherence to a Mediterranean diet was associated with higher levels of adiponectin,47 and higher levels of adiponectin are associated with a reduced risk of diabetes.

[Limitations—5 paragraphs!!]

Scientific Writing, HRP 214The Discussion Conclusion Our prospective cohort study suggests that

substantial protection against diabetes can be obtained with the traditional Mediterranean diet, rich in olive oil, vegetables, fruits, nuts, cereals, legumes, and fish but relatively low in meat and dairy products. The limited number of cases of diabetes and the possibility of under-reporting, however, requires that further larger cohorts and trials are needed to confirm our findings.

[Restatement of the findings—take home message]

The Discussion:

1. The answer to the key question asked2. What’s new3. The context

• How your results fit into, contradict, or add to what’s known or believed

4. Strengths and limits of the study5. The “so what?”: implicate, speculate, recommend6. Overall conclusion7. Powerful finish

Scientific Writing, HRP 214Discussion


Top 7


1. Peremptory v. preemptive

Peremptory = cannot be denied

Preemptive = action is one taken before an adversary can act

He issued a peremptory order.

He ordered a preemptive war in Iraq.

Scientific Writing, HRP 214 2. Subject v. patient

A subject is a volunteer.A patient is under treatment by a doctor.

The subjects in our study took a quiz about love.The patients in our study were being treated for their stomach

conditions.

Alternatives to “subject”: participants, volunteers, men, women, postmenopausal women, runners, smokers, etc.


3. Strata v. stratum

“Strata” is plural.“Stratum” is singular.

We analyzed the data, adjusting for the different age strata.

I was only interested in the association in the stratum of elderly subjects.


4. Averse v. adverse

Averse means “opposed” and usually describes a person’s attitude.

Adverse means “hostile, unfavorable, opposed” but usually applies to situations, conditions, or events—not people.

The bad weather has an adverse effect on my car.I would not be averse to trying that new restaurant.


5. Historic v. historical

Historic means notable in history. --indicates that it in some way changed the course of human events

Historical means relating to history or past events.--not necessarily historic

The signing of the Declaration of Independence was a historic moment in American history.

Professor Smith gave a historical lecture on the evolution of toothpicks.


6. Regardless vs. irregardless

Regardless: without regard forIrregardless: informal blend of regardless and

irrespective; would actually mean “with regard to” (double negative)

Use regardless!!I go walking every day regardless of season or weather.The allowance is paid regardless of age or income.


7. Ultimate and Penultimate

Ultimate: last (from Latin, ultimare=“come to an end”)Penultimate: second to last (paene=“almost”;

ultimas=“last”)

The ultimate aim was to force his resignation. The character was arrested in the penultimate

chapter, setting up the central tension of the final chapter.

Scientific Writing, HRP 214Homework for next time…

Assignments for Next Week• Read:

• Chapter 2 in Successful Science Writing

(3-units):Write intro/background using what you learned in

this week’s lectureWork on Letter to the Editor (due in two weeks,

along with Discussion section)

Documents

Scientific Writing, HRP 214 Weekly Quiz. A. It was a secret among friends. B. It was a secret between friends