Chapter 14 Patterns in Health and Disease: Epidemiology and Physiology

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Chapter 14Patterns in Health and
DiseaseEpidemiology and Physiology

• EXERCISE PHYSIOLOGY
• Theory and Application to Fitness and
  Performance, 6th edition
• Scott K. Powers Edward T. Howley

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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

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The Epidemiologic Triad
Figure 14.1
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Disease Control

• Destroying or removing the agent at its source
• Altering the environment to reduce transmission
  of the agent
• Improving the hosts resistance to the agent
• Altering the hosts behaviors
• Improved nutrition
• Immunization
• Exercise

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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

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Web of Causation
Figure 14.2
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Major Risk Factor Categories
Figure 14.3
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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

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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

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CHD Risk Factors

• Primary
• Increases risk of CHD in and of itself
• Secondary
• Increases risk of CHD if primary risk factor is
  present
• Cant be changed
• Can be changed

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Risk Factors for CHD

• Cant be changed
• Heredity
• Gender
• Age
• Race

• Can be changed
• Cigarette smoking
• High serum cholesterol
• High blood pressure
• Physical inactivity
• Diabetes
• Obesity
• Stress

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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

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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

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U.S. Population at Risk
Figure 14.4
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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

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Metabolic Syndrome
Figure 14.5
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Risk Factors for Metabolic Syndrome

• Abdominal obesity
• Waist circumference gt102 cm (men) and gt88 cm
  (women)
• Hypertriglyceridemia
• 150 mg/dl
• Low HDL cholesterol
• lt40 mg/dl (men) and lt50 mg/dl (women)
• High blood pressure
• 130/85 mmHg
• High fasting blood glucose
• 110 mg/dl

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Obesity

• Prevalence in US adults
• 65 are overweight (BMI 25.029.9 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