chapter 14 patterns in health and disease: epidemiology and physiology
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Chapter 14 Patterns in Health and Disease: Epidemiology and Physiology. EXERCISE PHYSIOLOGY Theory and Application to Fitness and Performance, 6th edition Scott K. Powers & Edward T. Howley. Epidemiology. - PowerPoint PPT PresentationTRANSCRIPT
Chapter 14
Patterns in Health and Disease:Epidemiology and Physiology
EXERCISE PHYSIOLOGYTheory and Application to Fitness and Performance,
6th editionScott K. Powers & Edward T. Howley
Epidemiology
• The study of the distribution and determinants of health states and the use of this information in the control of disease
• Uses of epidemiology:– Establish the cause of disease– Trace the natural history of disease– Describe the health status of populations– Evaluate an intervention
• Epidemiologic triad– Shows connections between the environment, agent,
and host that cause disease
The Epidemiologic Triad
Figure 14.1
Disease Control
• Destroying or removing the agent at its source• Altering the environment to reduce
transmission of the agent• Improving the host’s resistance to the agent• Altering the host’s behaviors
– Improved nutrition– Immunization– Exercise
Web of Causation• Difficult to establish the cause of chronic diseases
– Cardiovascular disease• Complex involvement of factors
– Risk factors– Genetic
• Heredity– Environmental
• Stress– Behavioral
• Diet• Smoking• Physical activity
Web of Causation
Figure 14.2
Major Risk Factor Categories
Figure 14.3
Leading and Actual Causes of Death
• Leading causes of death– Heart disease– Cancer– Stroke– Chronic lung
disease– Unintentional injuries– Diabetes
• Actual causes of death– Tobacco– Diet and physical
inactivity– Alcohol consumption– Infection– Toxic agents– Motor vehicles– Firearms
Coronary Heart Disease (CHD)
• Associated with atherosclerosis– Thickening of the inner lining of arteries– Contributor to heart attack and stroke death
• Diseases of the heart and blood vessels are the leading cause of death in the U.S.
• Associated with risk factors– Each risk factor magnifies the risk of CHD– Eliminating a risk factor causes a
disproportionate reduction in risk
CHD Risk Factors
• Primary– Increases risk of CHD in and of itself
• Secondary– Increases risk of CHD if primary risk factor is
present• Can’t be changed• Can be changed
Risk Factors for CHD
• Can’t be changed– Heredity– Gender– Age– Race
• Can be changed– Cigarette smoking– High serum
cholesterol– High blood pressure– Physical inactivity– Diabetes– Obesity– Stress
Determining Association Between Risk Factor and Disease
• Temporal Association• Plausibility• Consistency• Strength of association (relative risk)• Dose-response relationship• Reversibility• Study design• Judging the evidence
Physical Inactivity as a Risk Factor
• Independent risk factor for CHD• Relative risk of CHD is similar to other risk
factors– Smoking – High cholesterol – High blood pressure
• High population attributable risk– Percentage of population at risk– Due to large number of inactive individuals
U.S. Population at Risk
Figure 14.4
Metabolic Syndrome• Potential causative connections between risk factors
– Hypertension– Obesity– Insulin resistance– Dyslipidemia
• Leads to additional conditions– Hyperinsulinemia– Increased SNS activity– Increased blood volume– Increased resistance to blood flow
Metabolic Syndrome
Figure 14.5
Risk Factors for Metabolic Syndrome
• Abdominal obesity– Waist circumference >102 cm (men) and >88 cm
(women)• Hypertriglyceridemia
– ≥150 mg/dl• Low HDL cholesterol
– <40 mg/dl (men) and <50 mg/dl (women)• High blood pressure
– ≥130/85 mmHg• High fasting blood glucose
– ≥110 mg/dl
Obesity
• Prevalence in US adults– 65% are overweight (BMI = 25.0–29.9 kg/m2)– 30% are obese (BMI = ≥30.0 kg/m2)
• Linked to risk of CHD and metabolic syndrome
• Healthy People 2010 objectives for control of overweight and obesity– Nutrition objectives– Physical activity objectives