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Unit 5 – Public HealthChronic Diseases
Chapter 11 – The Biomedical Basis of Chronic Diseases
Chronic DiseasesNow leading causes of death and disabilityMultiple causes – risk factorsLong period of onsetPossibility of secondary preventionImportance of animal models
Cardiovascular Disease, ctd.Total cholesterol level – low is better
Low density lipoprotein (LDL) – low is better High density lipotrotein (HDL) – high is better
Genetics are a major factorExercise lowers total cholesterol and increases HDLSmoking lowers HDLWidespread use of statins for secondary prevention
Cardiovascular DiseaseAtherosclerosisHeart disease and strokePlaque begins at an early age in U.S.American diet raises risk Diet, high blood pressure, diabetes, smoking interact to
cause injury of artery walls
Hypertension -- High Blood PressureImportant risk factor for cardiovascular diseaseEssential hypertension” – no known causeObesity, smoking, stress may be risk factorsRole of salt140/90 was considered borderline of high blood pressure;
guidelines have been lowered to 120/80. Secondary prevention is effective
CancerNot one disease, but many; each has different risk factors,
treatments, etc.Arises from mutations in DNAMutations caused by chemicals, viruses, radiationDiet and hormones play a roleTobacco use causes one-third of cancer deathsTesting chemicals for carcinogenicity is complex
DiabetesMajor cause of disabilityPrevalence is rising in US along with obesity Deficiency in the body’s ability to metabolize sugarType 1 diabetes – childhood onset; failure of insulin-
producing cells of pancreasType 2 diabetes – “adult onset;” insulin resistanceType 2 diabetes closely correlated with obesityTreatable, but need long-term monitoring; need good
access to medical care
Complications of DiabetesBlindnessKidney FailurePoor wound healingAmputations of the extremities
Other Chronic Disease of Public Health ImportanceAlzheimer’s disease and other dementiasArthritis
Unit 5 – Public HealthChronic Diseases
Chapter 12 – Genetic Diseases and Other Inborn Errors
Environmental TeratogensInfectious pathogens – syphilis, rubella, toxoplasmosisEnvironmental chemicals – e.g., mercuryDrugs – e.g., thalidomide, Accutane, hormonesAlcohol
Genetic DiseasesChromosomal abnormalities – e.g., Down syndromeMendelian genetics
Autosomal dominantAutosomal recessiveX-linked
May be caused by new mutationsSeverity of some genetic conditions may be affected by
environment -- e.g. anencephaly and spina bifidaFolic acid supplements can reduce risk
Genes influence susceptibility to diseases of adulthood
Newborn ScreeningTest drop of blood from newborns for metabolic
abnormalitiesAll newborns in US are screened for at least two
conditions: PKU and hypthyroidismStates vary in conditions screened for Most conditions are autosomal recessiveEarly diagnosis can prevent or reduce permanent
damageSome conditions are complicated to test for: e.g.
cystic fibrosis
Carrier Screening Screen for recessive genes in high-risk populationsTay-Sachs disease in Jews
Encouraged by Jewish leadersSickle cell disease in African Americans
Screening program in 1970s was misunderstood and poorly conducted
Prenatal DiagnosisOnly remedy may be abortionDown syndromeAnencephaly and spina bifida
Genomic MedicineHuman Genome ProjectMany potential benefitsMany dilemmasCancer genes: e.g. BRCA1 and BRCA2Targeted therapies
Guidelines for Genetic ScreeningNewborn screening only when benefits the newborn,
when can confirm diagnosis and when treatment and followup are available for infants
Carrier identification should be voluntary and confidential and include counseling
Prenatal diagnosis should be include education and counseling
All tests of high quality, evaluated by FDA; government oversight of laboratory proficiency
More education for the general public about genetics