Health and Disease Metrics

Lecture 2: Introduction to the Epidemiology of Non-Communicable Diseases

• Non-communicable diseases (NCDs) are a broad range of conditions not transmitted from person-to-person
• Key NCDs include cardiovascular disease (CVD), cancer, type 2 diabetes mellitus, and chronic obstructive pulmonary disease (COPD)
• Other NCDs include injuries, mental disorders, and reproductive disorders
• Many NCDs increase in prevalence with age, often sharing common risk factors.
• This leads to co-morbidities (multiple conditions) in older adults.

Outline

• Introduction to NCDs and the Global Burden of Disease (GBD)
• Epidemiological transition
• NCD risk factors (upstream and downstream)
• Reproductive health
• Cardiovascular disease and type 2 diabetes
• Cancer
• Respiratory diseases

What are Non-Communicable Diseases?

• NCDs span a wide variety of conditions that are not contagious
• Major focus: CVD, cancer, type 2 diabetes mellitus, and COPD
• Can also include injuries, mental disorders, and reproductive disorders
• Some may have an infectious origin (e.g., HPV)
• Prevalence increases with age and some share risk factors

Non-Communicable Disease Epidemiology

• Generally focused on specific conditions (e.g., cancer epidemiology) rather than a general NCD epidemiology
• Key determinants of chronic diseases (unhealthy diet, physical inactivity, and tobacco use) are greatly affected by globalization
• Global Burden of Disease (GBD) study: comprehensive research analyzing health loss due to diseases, injuries, and risk factors worldwide

The Global Burden of Disease

• Infectious diseases and neonatal conditions were dominant in 1990
• In 2015, lower respiratory infections were among the leading causes of global Disability-Adjusted Life Years (DALYs)
• DALYs combine premature mortality and non-fatal health outcomes

Epidemiologic Transition

• NCDs are increasing globally as countries undergo epidemiological transitions
• Death rates from infectious diseases decline while NCD-related disorders increase
• WHO uses a three-level classification of diseases and mortality:
  • Group 1: Communicable diseases including maternal, perinatal, and nutritional disorders
  • Group 2: Non-communicable diseases
  • Group 3: Intentional or unintentional injuries

Double Burden of Disease

• LMIC face a double burden of communicable and non-communicable diseases during epidemiological transitions
• Globally, combined burden requires resources for prevention, control, and treatment

NCD Risk Factors

• Specific to the disease and global factors
• Global factors often operate at a level beyond individual or country control
• Factors influencing NCDs include urbanization/industrialization, modernization, urban culture, alterations in diets, reduced physical activity, loss of traditional cultural values, migration from rural to urban areas, and poverty

NCD: Upstream and Downstream Determinants

• Upstream determinants: macro-level factors (e.g., globalization, community characteristics) affecting health
• Downstream determinants: individual or micro-level factors (e.g., genetics, age, behaviors, blood pressure) influencing health

Life-course Perspective

• How individuals respond to macro-level factors throughout life
• Factors at any point in life can influence individual health determinants

Social Determinants of NCD

• Neighborhood effects (compositional and contextual effects including social networks and culture)
• Structural characteristics influence obesity risk
• Social networking effects on obesity influence individual obesity and health

Built Environment and NCD Risk Factor Distributions

• Built environment: human-made structures (e.g., parks, lakes)
• Physical activity influenced by urban landscapes, access to open spaces, and transportation
• Food environment: location, type, and number of food outlets, food quality, and prices
• Food and tobacco labeling affect items within the built environment

Trade Agreements, Nutrition, and NCD Risk Factors

• Trade agreements influence agricultural production, foodstuffs trade, and food processing
• Trade agreements shape food systems and access to food availability/food consumption.

Nutrition Transition

• Urbanization, economic growth, and technological change affect work, leisure, and food processing
• Transition stages: receding famine, degenerative disease, behavioral changes

Agricultural Policies, Climate Change, and NCD Risk Factors

• Three main types of agricultural policies: agricultural input, production, and trade policies

Agricultural Policies and Production Practices and Diet

• Relationship between agricultural policies, production practices, and diet
• Input policies, production policies, and trade policies impact food output, availability, price, and quality leading to consumer food choices and risk of obesity

Agriculture, Climate Change, and Health

• Livestock production contributes to climate change through deforestation, energy and water consumption, and NOx emissions

McMichael et al. "Contraction and Convergence Policy"

• High-income countries (HICs) reducing animal source food consumption to lower the overall meat consumption levels to which low-income countries (LMICs) will converge
• This policy change might impact NCDs (e.g., heart disease)

Reproductive Health

• Understanding reproductive health is vital for overall health of individuals and populations
• Covers conception, pregnancy, childbirth, and neonatal period

Reproductive Health: Maternal Mortality

• Maternal mortality: death of a woman during pregnancy or within 42 days of pregnancy termination related to factors associated with pregnancy
• Direct deaths: obstetric complications, interventions, omissions, or an associated chain of events
• Indirect deaths: pre-existing disease aggravated by pregnancy physiological effects.
• Maternal mortality ratio: number of deaths per 100,000 live births

Reproductive Health: Estimates of Maternal Mortality Ratio by Country

• Map showing maternal mortality rates by country

Reproductive Health: Stillbirth

• Stillbirth definitions and types including gestational age and causes
• Common causes of stillbirth

Reproductive Health: Neonatal Deaths

• Neonatal mortality rates by region

Cardiovascular Diseases and Type 2 Diabetes

• Cardiovascular diseases (CVD): encompass various heart and blood vessel conditions
• Type 2 diabetes mellitus: condition where body cannot regulate glucose levels effectively
• Defining features, types, and medical standards for diagnosis

Cardiovascular Diseases: The Global Burden of Disease Study (2019)

• Data on the global burden of cardiovascular diseases

Diabetes Epidemiology

• Type II diabetes is prevalent globally
• Type I diabetes incidence is less clear in low-income countries and has high mortality among affected children in those populations.

Cardiovascular Diseases and T2 Diabetes: Factors

• Risk factors include lifestyle changes, high blood pressure, obesity, smoking, high LDL cholesterol, and physical inactivity

CVD and T2D factors: Blood Pressure

• Systolic blood pressure and age impact CVD

CVD and T2D factors: Obesity

• Obesity is a medical condition linked to negative health effects.
• BMI is used to measure obesity.

CVD and T2D factors: Smoking

• Smoking has a strong positive association with all-cause mortality over a 12-year period

CVD and T2D Factors: Cholesterol

• Correlation between LDL and HDL cholesterol and CVD risk

Cancer Epidemiology

• One of the most common causes of death worldwide
• Affects all age groups
• Over 100 types with primary body area as naming classifications

Cancer: Biology

• Cancer development process in terms of cell mutations, and cellular stages of development

Cancer Characteristics

• Cancer characteristics such as proliferation, immortalization, resisting cell death, angiogenesis, evasion of growth suppressors, and activating invasion and metastasis

Cancer Types

• Classification of cancers including some common carcinomas (Lung, Breast, Colon, Bladder, Prostate) and sarcomas (fat, bone, and muscle)

Cancer Staging

• Staging system used to assess the extent of cancer based on tumour characteristics and spread

Cancer Detection

• Detection methods including clinical examinations, imaging, endoscopy, screening

Cancer: Measuring Burden

• Measuring cancer burden using prevalence, incidence, and mortality, including the development over time

Common Cancers: Trends

• Overview of common cancer types and trends in their incidence and survival, including geographic variations(such as developed vs developing nations)

Cancer: Prevention

• Potential of preventing cancer using preventative measures and risk factors such as smoking

Respiratory Diseases: COPD and Asthma

• Chronic obstructive pulmonary disease (COPD) and asthma are prevalent respiratory diseases.
• COPD is a slowly progressing and irreversible lung disease
• Asthma has reversible airflow limitation and typically involves fluctuations and is manageable

COPD and Asthma: Burden

• Describes factors impacting the burden of COPD and asthma including substantial healthcare costs, loss of productive days, and relationship to other conditions

Asthma Prevalence

• Prevalence of asthma symptoms (e.g., wheeze) varies geographically

COPD: Burden

• Impacts of COPD, such as disability, daily function impairment, high healthcare costs, and frequent hospitalisations

COPD Prevalence

• Prevalence of COPD, and age-related differences

Asthma: Genetic and Environmental Risk Factors

• Genetic and environmental factors impacting asthma

COPD: Genetic and Environmental Risk Factors

• Genetic and environmental risk factors, including gender, age, SES, smoking, and air pollution

Thank You! Questions?

• Concluding statement

This quiz covers essential health metrics such as blood pressure measurement, BMI classifications, and the relationship between smoking and cardiovascular disease. It also delves into mortality rates, lifestyle risk factors, and trends in different income countries. Test your knowledge on key health statistics and their implications!