Social factors, health policy, and environment: implications for cardiovascular disease across the globe
Why do people in different parts of the world have such different risks of getting heart disease, and what can we do about it? Instead of just telling individuals to "eat better and exercise more," this research examines how to create environments where healthier choices are easier for everyone, regardless of where they live or how much money they have.
College of Health researcher(s)
Abstract
Cardiovascular disease (CVD) is the leading cause of deaths worldwide, with 80% occurring in low- and middle-income countries. These countries are characterized by rapid urbanization, poorly funded health systems, poor access to prevention and treatment strategies, and increasing age and a higher prevalence of chronic disease. Rapid urbanization has contributed to the significant environmental and societal changes affecting daily life habits and cardiovascular health. There is growing awareness that environmental and social exposures and policies can influence CVD directly or through behavioural risk factors. However, much of this knowledge comes from studies in high-income countries and is applied to low- and middle-income countries without evidence to indicate this is appropriate. This state-of-the-art review will present and synthesize key findings from the Prospective Urban Rural Epidemiology study and related studies that have aimed to understand the environmental, social, and policy determinants of cardiovascular health in countries across varying levels of economic development through an urban/rural lens. Emerging from these findings are future policy and research recommendations to accelerate the reduction of the global burden of CVD.
Frequently Asked Questions: Global Cardiovascular Disease Factors
What are the main environmental and social factors influencing cardiovascular disease (CVD) globally, and how do they differ across income levels?
Environmental factors like air pollution (both outdoor and household), and the built environment (which affects physical activity and food access) play a significant role in CVD risk. Social factors such as socioeconomic status (education and economic resources), social isolation, and access to healthcare and medications are also major determinants. The impact and prevalence of these factors vary significantly by country income level. Low- and middle-income countries (LIC and MIC) face challenges like rapid urbanization with poorly funded infrastructure, greater exposure to household air pollution from solid fuels, lower availability and affordability of healthy food options and essential CVD medications, and higher rates of tobacco marketing compared to high-income countries (HIC). While HIC have better access to prevention and treatment strategies, socioeconomic disparities within these countries still lead to higher CVD risk among disadvantaged populations.
How does urbanization specifically impact cardiovascular health in different income settings?
Urbanization presents both challenges and opportunities for cardiovascular health. In HIC, urban environments with features like multi-purpose land use, street connectivity, green spaces, and public transit are generally associated with increased physical activity and better access to healthy food and healthcare. However, in LIC and MIC, rapid urbanization can lead to overcrowded conditions, poor infrastructure, increased traffic, and safety concerns, which can hinder physical activity despite higher population density. While urban areas across all income levels generally offer better access to education, healthcare, and healthy food compared to rural areas within the same country, the affordability of these resources remains a significant barrier in LIC and MIC. Urbanization in LIC and MIC can also concentrate environmental exposures like air pollution.
What are the key findings from the Prospective Urban Rural Epidemiology (PURE) study regarding environmental, social, and policy determinants of CVD?
The PURE study, a large-scale, multi-country cohort study, is uniquely positioned to investigate the impact of diverse environmental, social, and health systems conditions on CVD across different economic development levels. Key findings include: non-recreational physical activity (occupational, transportation, domestic) is more dominant in LIC, while recreational activity is higher in HIC. Availability and affordability of fruits and vegetables are lower in LIC and MIC, particularly in rural areas, leading to lower consumption of these healthy foods compared to HIC. Tobacco marketing is significantly more prevalent in LIC and MIC. Social isolation is more common in MIC and HIC, and urban residents are more likely to be socially isolated. Crucially, access to essential CVD medications is drastically lower in LIC and MIC, contributing to higher mortality rates despite potentially lower overall risk factor burdens in some cases compared to HIC. Outdoor air pollution is associated with increased CVD risk across all income levels, and household air pollution from solid fuels is a major risk factor, especially in rural areas of LIC and MIC.
How does the food environment influence dietary habits and CVD risk across different country income levels?
The food environment, including the pricing and availability of nutrient-dense foods, significantly impacts dietary quality and subsequent CVD risk. Healthy foods are often more expensive than less nutritious, calorie-dense options, making healthy diets less accessible for socially and economically disadvantaged individuals. The PURE study found that fruit and vegetable consumption is lowest in LIC, where these foods are least affordable relative to income. While urban areas generally have better availability of fruits and vegetables than rural areas, the relative cost is still higher for rural residents across all income levels. The density of fast-food restaurants and bars has been associated with higher obesity rates, while the presence of food markets is negatively associated with obesity.
What is the role of tobacco use and the tobacco environment in contributing to the global burden of CVD?
Tobacco use is a leading preventable cause of CVD deaths globally, with the majority of users residing in LIC and MIC. The increased risk of CVD associated with smoking varies somewhat across income levels, potentially due to differences in product use. Effective tobacco control policies (price increases, restrictions on availability and marketing) have been primarily implemented in HIC. However, LIC and MIC are increasingly adopting these policies. The PURE study demonstrated that visible non-smoking signs and social unacceptability of smoking are much higher in HIC, coinciding with greater knowledge of health consequences and higher quit rates. The tobacco industry has shifted its marketing efforts towards LIC and MIC, with higher densities of tobacco retail outlets and significantly more visible marketing in these regions.
How do education and economic factors contribute to disparities in CVD risk and outcomes?
Lower socioeconomic status, often measured by low education and limited financial resources, is strongly associated with increased CVD risk, particularly in HIC. This link is mediated through various pathways, including a higher prevalence of modifiable risk factors like obesity, diabetes, smoking, and physical inactivity, as well as reduced access to effective healthcare. The PURE study confirmed this association across all income levels, showing that individuals with the lowest education levels have the highest mortality rates. Given the significant proportion of the population in LIC and MIC with primary education or less, education is identified as a crucial modifiable risk factor for reducing CVD burden.
How does social isolation affect cardiovascular health, and are these effects consistent across different income levels?
Social isolation, defined as the absence of sufficient social relationships, has been linked to an increased risk of premature mortality, including from CVD and stroke. This association has been observed in both HIC and LIC. The PURE study found that social isolation is associated with a greater risk of premature mortality, incident stroke, and CVD across 20 countries, regardless of income level. While social isolation was more prevalent in MIC and HIC and in urban areas, its negative impact on cardiovascular health was evident everywhere. The study suggests that part of this association might be mediated through behavioral risk factors and comorbidities, although other factors may also play a role. Social capital, characterized by trust and cooperation, may help mitigate the negative effects of social isolation, particularly in LIC and MIC where healthcare access is limited.
What are the implications of the PURE study findings for future health policies and research to reduce the global burden of CVD?
The findings from the PURE study highlight the need for a multi-sectoral approach to reduce the global burden of CVD, going beyond traditional individual risk factor interventions. Key implications for policy and research include: increasing the number of multi-country studies in diverse settings to understand the context-specific influences of environmental and social factors; raising awareness of barriers to implementing evidence-based policies, such as obstruction by commercial interests; integrating opportunities for physical activity, access to healthy food, and improved air quality into urban and regional planning, while considering the local context; and addressing the critical issue of access and affordability of essential CVD medications, particularly in LIC and MIC, as this is a major determinant of outcomes. The study emphasizes the need for policies that address the upstream determinants of health and acknowledges that interventions effective in HIC may not be directly applicable to LIC and MIC without careful consideration of local conditions.