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Health Effects of Tobacco Use & Exposure to
Second Hand Smoke
Roberta Ferrence
Ontario Tobacco Research Unit
Dalla Lana School of Public Health
September 17, 2014
Ontario Tobacco Research Unit
Tobacco as Medicine 16c Used to alleviate
discomfort 17c Belief that smoking
provided protection from the plague
1614 a Scottish doctor praised tobacco, which “prepareth the stomach for meat; it maketh a clear voice: it maketh a sweet breath… in a few words, it is the princess of physical plants”
Ontario Tobacco Research Unit
However, others disagreed…
"loathsome to the eye, hateful to the nose, harmful to the brain" and "dangerous to the lungs.”
- King James I (1604):
‘A Counterblaste to Tobacco’
Ontario Tobacco Research Unit
…and were amazingly accurate
19c Anti-tobacco crusade Dr. Joel Shew of England attributed delirium tremens, impotency, insanity and cancer to effects of smoking and chewing.
Ontario Tobacco Research Unit
20c Thinking on Tobacco
Cigarettes = “Coffin nails” Irritation model:
Cigarettes thought safer since less irritating than other forms of tobacco
Underlying health concern in ads: 1936: “Ask your doctor
about a light smoke” 1946: “More doctors smoke
Camels”
Ontario Tobacco Research Unit
Landmarks in Early Scientific Knowledge on Smoking and Health
1939: Muller finds statistical link between smoking and cancer in small-scale study
1950: 3 large-scale epidemiological studies linking smoking to lung cancer (Levin, Wynder & Graham, and Doll & Hill)
1952: Doll and Hill conclude "association between smoking and carcinoma of the lung is real"
Ontario Tobacco Research Unit
Two Firsts
1953: Wynder, Graham and Croninger show cigarette tar painted on mice causes tumours
First lab evidence for carcinogenic effect of smoking
First evidence for carcinogens in “Thirdhand Smoke”
Ontario Tobacco Research Unit
More Early Epidemiology
1954: Doll and Hill publish first results of British Doctors Study: Smoking associated with increased lung cancer and contributes to heart disease
1956: Auerbach: Dose Response Smoking induces precancerous changes in lung that
increase with amount smoked & decline after quitting.
Doll and Hill: Mortality Lung cancer mortality in heavy smokers x 20
nonsmokers; death rates decline in proportion to length of time
since stopping.
Ontario Tobacco Research Unit
Establishing a Causal Relationship
1957: The British MRC conclude "direct causal connection" between smoking and lung cancer
1958: Hammond and Horn report smoking causes lung cancer and coronary artery disease
1962: Royal College of Physicians concludes smoking causes lung cancer, bronchitis; probably contributes to coronary heart disease and other diseases
Ontario Tobacco Research Unit
1964 Surgeon General’s Report on Smoking and Health
Based on 7000 articles relating to smoking and disease
Concluded that cigarette smoking is a:
Cause of Lung & Laryngeal Cancer in men
Probable cause of Lung Cancer in women
Most important cause of Chronic Bronchitis in both sexes
Ontario Tobacco Research Unit
The Health Consequences of Smoking: Reports of the US Surgeon General
Number of diseases and conditions associated with tobacco use skyrocket
(SGRs 1979, 1985, 1989, 2004, 2014)
Reports on specific groups (Youth 1994, 2012, Minorities 1998, Women 1980, 2001), Diseases (CVD 1983, Lung disease 1984) Cessation 1990, Secondhand Smoke 1984, 2006 and Addiction 1988
Ontario Tobacco Research Unit
Tobacco is Addictive: US
1988: The Health Consequences of Smoking: NICOTINE ADDICTION, A Report of the US Surgeon General concluded:
Cigarettes and other forms of tobacco are addicting
Nicotine: drug in tobacco that causes addiction Pharmacologic and behavioral processes that
determine tobacco addiction are similar to those that determine addiction to heroin and cocaine
Ontario Tobacco Research Unit
Tobacco is Addictive: Canada
1989: Royal Society of Canada, Tobacco, Nicotine and Addiction concluded:
“Cigarette smoking can and frequently does meet all the criteria for addiction”
Nicotine is the addictive agent in tobacco
Ontario Tobacco Research Unit
Health Effects of Tobacco UseCurrent Evidence
SGR 2010: How Tobacco Causes Disease
SGR 2014: The Health Consequences of Smoking: 50 Years of Progress
Ontario Tobacco Research Unit
Carbon Monoxide
Decreases availability of oxygen in blood increasing risk of heart attack
Slows oxidation processes Direct effects on
Cardiac function Heart structure Blood vessels
Raises cholesterol levels, white blood cells counts and other risk factors for heart disease
Ontario Tobacco Research Unit
“Tar” and Smoke
GasesParticulates: Heart and Respiratory effectsCell damage: CancerDifferent effects at different stages of
lifespan
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NicotinePhysiological effects
Acetylcholine Releases catecholamines (dopamine etc.) Increases heart rate, respiration and BP Increases blood glucose levels
Rate of absorption determines CV effects Fast “bolus” for smoking Slow release for patch, gum
Environmental effects Combines with nitrous acid indoors and forms new
tobacco-specific carcinogens
Ontario Tobacco Research Unit
More on Nicotine
Acute toxicity Activates many pathways to increase risk of
disease Prenatal exposure adversely affect brain
development Contributes to preterm delivery and stillbirth May affect adolescent brain development Increases vascularization, which may promote
tumor growth, atherosclerosis or spread cancer May predispose to obesity and diabetes May prime brain for cocaine use
Ontario Tobacco Research Unit
Tobacco and Cardiovascular Disease
Smoking causes:
More deaths from CVD than Cancer
Ischemic Heart Disease Stroke Peripheral
vascular disease Aortic Aneurysm Type II Diabetes (Dose
Response)
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Not just Lung Cancer Lip, Oral cavity, Nasal, Paranasal sinus,
Pharynx, Larynx and Esophagus Urinary Bladder and Ureter Kidney Liver Colorectal Pancreas Uterine Cervix Stomach Bone marrow (myeloid leukemia) Suspected cause of breast cancer
Ontario Tobacco Research Unit
Continued Smoking Affects Cancer Patients
Increase in adverse health outcomes Quitting smoking improves outcomes Increased risk of dying of any cause Increased risk of secondary cancersMay raise risk of recurrence, poorer
response to treatment, and increased toxicity from treatment
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Effects of Smoking on Prostate Cancer
No evidence at this point for causal relationship
May have higher risk of deathMay have higher risk of advanced-stage
disease and risk of progression
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Smoking Causes Respiratory Disease
COLD or COPD Pneumonia, Asthma, TB Children and Adolescents:
impaired lung growth, coughing, phlegm, wheezing, asthma symptoms
Adults: Decline in lung function May cause Idiopathic
pulmonary fibrosis
Ontario Tobacco Research Unit
Smoking Causes Reproductive Effects
Fetal death and stillbirths SIDS Ectopic pregnancy
Reduced fertility in mother and offspring Low Birth Weight, shortened gestation and
preterm delivery Orofacial clefts and other birth defects Other pregnancy complications
Ontario Tobacco Research Unit
Other Effects
Immune disorders: Rheumatoid arthritis Cataracts, AMD, Respiratory and healing complications of
surgery Low Bone Density Hip Fractures Peptic Ulcer Disease, if helicobacter
pylori positive
Ontario Tobacco Research Unit
Smoking Likely Causes
Breast Cancer in all women Root surface Dental Caries Failure of dental implants Erectile Dysfunction (ED) Multiple Sclerosis Crohn’s Disease
Ontario Tobacco Research Unit
Smoking and Lung Cancer
Most lung cancer related to smoking in West: 75% of cases in women 84% of cases in men
In Asia, 65%-95% occur in non-smokers 1.2 M cases worldwide and increasing 5 yr. survival: 15% Duration of smoking & amount smoked Interacts with radon, asbestos, high heat
cooking
Ontario Tobacco Research Unit
Smoking & Breast Cancer
New research shows increased risk
among heavy and long term smokers Important interaction with Second Hand
Smoke Misclassification Expert Panel on Tobacco Smoke and
Breast Cancer (2009) “The relationships between active smoking and
both pre- and post-menopausal breast cancer are consistent with causality.”
Ontario Tobacco Research Unit
Smokeless Tobacco (ST)
Wet Snuff and chewing tobacco
Chewing tobacco and snuff contain 28 cancer-causing agents. Most harmful are
tobacco-specific nitrosamines (TSNAs)
Formed during growing, curing, fermenting, and aging of tobacco.
Ontario Tobacco Research Unit
Smokeless Tobacco (ST) Many other carcinogens in ST Oral cancer Nicotine in ST
3-4 times amount delivered by a cigarette Absorbed more slowly than from cigarettes More nicotine per dose absorbed Stays in bloodstream longer Cardiovascular effects and nicotine addiction
Relationship with CVD, diabetes and reproductive effects under study
Ontario Tobacco Research Unit
Smokeless Tobacco (ST)
Formation of additional carcinogens depends on processing and storage
Swedish ST (“snus”) may have fewer carcinogens than average North American ST
New evidence for increased cancers (pancreatic)
Health risk may be as low as 10% of that for cigarettes; still a 2-fold risk.
Insufficient research at this point
Ontario Tobacco Research Unit
Quitting at any age provides major health benefits
No elevated risk of lung cancer if quit < age 30 At age 50, risk of death is reduced by 50%
compared to continuing smokers At age 40, 50% less risk than at age 50 Even at advanced ages, immediate respiratory,
cardiac and wound healing benefits, reduced CHD risk and some reduction in cancer risk
Reduction in Risk after Quitting
Ontario Tobacco Research Unit
What is Second Hand Smoke?
SHS formed from smoldering a cigarette or other tobacco product
Smoke exhaled by smoker
Fetal exposure comes from mother’s active smoking and other SHS in environment
Ontario Tobacco Research Unit
History of Evidence on SHS
1979 SGR: several adverse respiratory outcomes + acute cardiovascular effects
1982 SGR raised concern re lung cancer1992 EPA concluded SHS:
Caused lung cancer and lower respiratory illnesses in children
Type A carcinogen1997 Cal EPA, 1998 UK, 1999 WHO
Ontario Tobacco Research Unit
2001: Second Hand Smoke causes:
In Adults: Heart disease, Lung cancer, Nasal sinus cancer
In Children: SIDS, Fetal Growth impairment, Low Birth Weight, Respiratory diseases, Asthma exacerbation, Middle ear disease
Ontario Tobacco Research Unit
SHS May also Cause: In Adults: Stroke, Breast
cancer, Cervical cancer, Miscarriages
In Children: Adverse impact on cognition and behaviour; Decreased lung function, Asthma induction, Worsening of Cystic Fibrosis
Second hand smoke exposure causes 1100 to 7800 deaths/yr in Canada.
Ontario Tobacco Research Unit
California Air Resources Board Report(2005)
Updates 1997 ReportConfirms previous report findingsNew Findings:
Paternal smoking causes childhood cancer
SHS is a cause of Breast Cancer in pre-menopausal women
SHS may increase risk of Cervical Cancer, Bladder Cancer
Ontario Tobacco Research Unit
Surgeon General’s Report(2006)
NO RISK-FREE LEVEL OF EXPOSURE TO SECONDHAND SMOKE
SHS causes premature death and disease in children and adult nonsmokers
SHS exposure has IMMEDIATE adverse effects on CV system and causes CHD and lung cancer
Similar findings to CAL EPA except breast cancer (“evidence is suggestive..”)
Ontario Tobacco Research Unit
Breast Cancer and Second-hand Smoke
Inconsistent findings on breast cancer and tobacco smoke.
2005 California ARB Report “…consistent with causality in younger, primarily pre-
menopausal women.” 2006 Surgeon General’s Report
“…suggestive but not sufficient to infer a causal relationship between second-hand smoke and breast cancer”
2009 IARC Report Supports findings of SGR
2014 SGR Same as 2006 report for breast cancer
Ontario Tobacco Research Unit
Expert Panel on Tobacco Smoke and Breast Cancer Risk (2009)
Findings Relationship between SHS and breast cancer in
younger, primarily pre-menopausal women is consistent with causality
Evidence is considered insufficient to pass judgment on SHS and post-menopausal breast cancer.
Ontario Tobacco Research Unit
Other Health Effects of SHS
20-30% increase in risk of strokeSmoke free policies reduce risk of coronary
events among adults under 65 yrsSF policies may reduce risk of CV events
Ontario Tobacco Research Unit
Methodological Issues in Establishing Causation
Too few studies that measured SHS exposure Exposure measures not always specific to site
or include childhood Too few disease cases to find significant
relationships Exposure data collected recently For some diseases, may be threshold effect
rather than dose response
Ontario Tobacco Research Unit
New Research on SHS Exposure
Substantial exposures occur indoors Smoke can travel in multi-unit dwellings Even when mother smokes outdoors, child still
has significant exposure Outdoor exposure can be equally hazardous
1-2 metres heaviest exposure 8-9 metres required for protection Eliminating awnings and umbrellas may not
make a difference
Ontario Tobacco Research Unit
Waterpipe (Hookah, Shisha,
Narghile) – Is it Safer
than Cigarette Smoking?
Ontario Tobacco Research Unit
Hookah & Waterpipe Smoking
Variability of nicotine content in tobacco hookah
Waterpipe smoking sessions (20-80 minutes) last longer than smoking a single cigarette (5-7 mins)
Greater volume of inhaled smoke during waterpipe session
Ontario Tobacco Research Unit
Waterpipe Smoke is Toxic
High levels of fine particulate matter, as much as cigarette smoking
More carbon monoxide in the blood More smoke exposure than cigarettesPossibly more nicotine exposure than
cigarettes
Ontario Tobacco Research Unit
Waterpipe Secondhand Smoke
Waterpipe smoke includes charcoal & tobacco smoke
Typical 1 hour session likely generates carcinogens & toxicants 3-200 times the amount in cigarette smoke (equivalent of 2-10 cigarettes)
Indoor air quality in hookah bars show high levels of CO
Ontario Tobacco Research Unit
Health Effects of Waterpipe Smoke Toxicants
Waterpipe sidestream smoke vs. cigarette sidestream smoke (from a single session) emits approximately:
4 x PAHs – causes cancer 4 x VAs – causes lung disease 30 x CO – contributes to CVD Nicotine – causes dependence
Ontario Tobacco Research Unit
Serious Health Effects
Respiratory illness (Likely cause of COPD) Reduced lung function Low birth-weight Periodontal disease Cardiovascular disease Nicotine/tobacco dependence Lung cancer Infectious diseases transmitted by shared
hookah
Ontario Tobacco Research Unit
Thirdhand Smoke
What remains in air, on surfaces and people after cigarette is extinguished
Off-gassing in indoor environments can continue for weeks, months, years
Outdoor contaminants can be carried indoors and transferred to infants & others
Causes DNA damage in humans
Ontario Tobacco Research Unit
E-Cigarettes
Increasing use, especially among youth and young adults despite HC ban
Exposures and risks not fully established: not just water vapour
No confirmed evidence for impact on cessation beyond regular NRT
Concerns that use will undermine smoking bans, increase social exposure and lead to increases in all tobacco and nicotine use
Ontario Tobacco Research Unit
Conclusion
Smoking and tobacco smoke exposure have major health effects and a corresponding burden of health and human costs
Efforts to eliminate smoking and smoke exposure will have a major impact on reducing exposure
Tobacco industry a major threat to reducing or eliminating tobacco use and exposure
Nevertheless, we have many ways to reduce the health burden of tobacco