Modern Trends and Chronic Diseases

Modern Trends and Chronic Diseases

• Increased prevalence of chronic diseases (e.g., obesity, cardiovascular disease, diabetes) correlated with modern sedentary lifestyles.
• Urbanization, technological advancements, and dietary changes contribute to reduced physical activity.

Key Definitions

• Physical Activity (PA): Any skeletal muscle movement requiring energy expenditure.
• Physical Inactivity: Insufficient PA levels below recommended guidelines.
• Sedentary Behavior: Prolonged sitting or reclining with minimal energy expenditure.
• Exercise: Planned, structured, and repetitive PA for improved fitness.
• Physical Fitness: Ability to execute daily tasks with vigor and alertness.
• Health: State of complete physical, mental, and social well-being.

PA in a Pandemic

• Piggin's Definition: Holistic, emphasizing social, mental, and emotional well-being, within PA.
• Casperson's Definition: Orthodox, focusing on bodily movement and energy expenditure.

Key Studies on PA and Health

• UK Double Decker Bus Study (Jeremy Morris): Conducted to investigate the link between occupational PA and heart disease. Found conductors, with higher PA, had lower heart disease rates.
• Harvard Alumni Study (Ralph Paffenbarger): A longitudinal cohort study. Showed higher PA linked to lower all-cause mortality.

Obesity Epidemic

• Defined as widespread increase in obesity, reaching a public health crisis. Measured through prevalence rates and health consequences.

Canadian Adult Obesity Clinical Practice Guidelines

• Obesity is a chronic disease impacting biological, behavioral, and environmental factors.

WHO Maps and Double Burden of Disease

• Simultaneous rise in undernutrition and obesity within populations.

Canadian 24-Hour Movement Guidelines

• Integrates physical activity, sedentary behavior, and sleep recommendations.

Trends in Obesity (2005-2018)

• Rising obesity rates, disparities in demographics, and policy implications were found in the research.

ISPAH Eight Investments for PA

• Systems-level approach to promoting physical activity, including active societies, environments, people, systems, schools, workplaces, urban design, and the health sector.

Epidemiology & PA Epidemiology

• Epidemiology: Study of disease distribution and determinants within populations.
• PA Epidemiology: Examines PA's role in disease prevention.

Key Measures in Epidemiology

• Incidence: New cases over time.
• Prevalence: Total cases at a point in time.
• Burden of Disease: Impact on populations, measured in DALYs.
• Cost of Illness: Economic impact.

Study Types in Epidemiology

• Observational: Cohort, case-control, cross-sectional.
• Experimental: Randomized controlled trials (RCTs).

Mortality Measures

• Cause-specific mortality: Deaths attributed to particular diseases.
• Case fatality rate: Proportion of cases resulting in death.
• Risk Ratio (RR) and Odds Ratio (OR): Statistical measures for association.
• Population Attributable Risk Fraction (PARF): Measures the proportion of disease cases attributable to a particular risk factor.

Measuring PA & Fitness

• Subjective Measures: Questionnaires (e.g., IPAQ), logs (easy, low cost but prone to bias).
• Objective Measures: Accelerometers, pedometers (accurate but expensive).

Accelerometer vs. Questionnaire PA Measures

• Interpretation of correlations between different measurement methods discussed.

Study Designs & Errors in Research

• RCTs: Gold standard.
• Issues: Bias, confounding, chance.

Establishing Causality (in epidemiological studies)

• Considerations: Temporality, consistency, plausibility.

PA & Mortality (Key Studies)

• Taylor et al. (1962) - US Railroad Employees: Showed higher PA was associated with reduced mortality.
• Harvard Alumni & Health ABC Studies: Consistent findings of reduced mortality risk with higher PA levels over time.
• Meta-Analysis (Accelerometer-Measured PA & Mortality): PA reduces all-cause mortality.
• Harvard Alumni Study - PA Change & Mortality: Increased PA reduces mortality risk.
• Meta-Analysis - Sitting Time & Mortality: PA mitigates risk from prolonged sitting.

Physical Fitness & Mortality (Key Studies)

• ACLS Study: Strong inverse relationship found between cardiorespiratory fitness and mortality. Low fitness was a more significant risk factor than obesity.
• Meta-Analysis - Fitness & Mortality: Higher fitness levels linked to significantly lower mortality risk. Dose-response relationship: greater fitness improvements yield larger reductions in mortality.
• Myers et al. Study: Higher fitness linked to reduced mortality in men, with and without cardiovascular disease (CVD).
• ACLS - Fitness vs. Other Risk Factors: Low fitness was a stronger predictor of mortality than factors like smoking, obesity, and hypertension. Emphasized that PA's benefit extends beyond weight management.

Fitness & Mortality by Weight Class

• Nurses' Health Study: PA reduced mortality risk across all BMI categories. Highlighted the importance of an active lifestyle, even for those with higher weights.
• Meta-Analysis: Fitness mitigates mortality across all BMI, regardless of weight. Being fit, even with higher weights, is more protective than being sedentary with a normal weight.

Interpreting Figures & Risk Ratios

• Relative Risk (RR): Measures the association between fitness and mortality risk.
• Confidence Intervals (CI): Assess the reliability of RR estimates.
• Dose-Response Trends: Show how increased fitness reduces mortality risk.
• Forest Plots & Meta-Analyses Graphs: Visualize fitness-mortality relationships and summarize findings of multiple studies.
• Risk Ratio Comparisons: Compare mortality risks of low-fit vs. high-fit individuals, highlighting fitness benefits that go beyond just body mass index.