The effect of physical activity on mortality and cardiovascular disease in 130 000 people from 17 high-income, middle-income, and low-income countries: the PURE study

Summary

Background

Physical activity has a protective effect against cardiovascular disease (CVD) in high-income countries, where physical activity is mainly recreational, but it is not known if this is also observed in lower-income countries, where physical activity is mainly non-recreational. We examined whether different amounts and types of physical activity are associated with lower mortality and CVD in countries at different economic levels.

Methods

In this prospective cohort study, we recruited participants from 17 countries (Canada, Sweden, United Arab Emirates, Argentina, Brazil, Chile, Poland, Turkey, Malaysia, South Africa, China, Colombia, Iran, Bangladesh, India, Pakistan, and Zimbabwe). Within each country, urban and rural areas in and around selected cities and towns were identified to reflect the geographical diversity. Within these communities, we invited individuals aged between 35 and 70 years who intended to live at their current address for at least another 4 years. Total physical activity was assessed using the International Physical Activity Questionnaire (IPQA). Participants with pre-existing CVD were excluded from the analyses. Mortality and CVD were recorded during a mean of 6·9 years of follow-up. Primary clinical outcomes during follow-up were mortality plus major CVD (CVD mortality, incident myocardial infarction, stroke, or heart failure), either as a composite or separately. The effects of physical activity on mortality and CVD were adjusted for sociodemographic factors and other risk factors taking into account household, community, and country clustering.

Findings

Between Jan 1, 2003, and Dec 31, 2010, 168 916 participants were enrolled, of whom 141 945 completed the IPAQ. Analyses were limited to the 130 843 participants without pre-existing CVD. Compared with low physical activity (<600 metabolic equivalents [MET] × minutes per week or <150 minutes per week of moderate intensity physical activity), moderate (600–3000 MET × minutes or 150–750 minutes per week) and high physical activity (>3000 MET × minutes or >750 minutes per week) were associated with graded reduction in mortality (hazard ratio 0·80, 95% CI 0·74–0·87 and 0·65, 0·60–0·71; p<0·0001 for trend), and major CVD (0·86, 0·78–0·93; p<0·001 for trend). Higher physical activity was associated with lower risk of CVD and mortality in high-income, middle-income, and low-income countries. The adjusted population attributable fraction for not meeting the physical activity guidelines was 8·0% for mortality and 4·6% for major CVD, and for not meeting high physical activity was 13·0% for mortality and 9·5% for major CVD. Both recreational and non-recreational physical activity were associated with benefits.

Interpretation

Higher recreational and non-recreational physical activity was associated with a lower risk of mortality and CVD events in individuals from low-income, middle-income, and high-income countries. Increasing physical activity is a simple, widely applicable, low cost global strategy that could reduce deaths and CVD in middle age.

Funding

Population Health Research Institute, the Canadian Institutes of Health Research, Heart and Stroke Foundation of Ontario, Ontario SPOR Support Unit, Ontario Ministry of Health and Long-Term Care, AstraZeneca, Sanofi-Aventis, Boehringer Ingelheim, Servier, GSK, Novartis, King Pharma, and national and local organisations in participating countries that are listed at the end of the Article.

Introduction

Cardiovascular disease (CVD) is the leading cause of death worldwide¹ and a major economic global burden.² Despite reductions in CVD mortality in high-income countries, global CVD mortality increased by 41% between 1990 and 2013, largely driven by rises in low-income and lower-middle-income countries.³ Indeed, 70% of global CVD deaths come from low-income and middle-income countries, where it is the commonest cause of death.4, 5 23% of the world's population is estimated to be insufficiently active⁶ and WHO has recommended a decrease in insufficient physical activity of 10% (of the aforementioned 23%) by 2020.⁷

Many studies from high-income countries have reported significant inverse associations of physical activity with mortality and CVD morbidity,⁸ but such data from low-income and middle-income countries are sparse and limited to a few small studies.9, 10, 11 Moreover, studies of physical activity have focused primarily on recreational physical activity (which is common in high-income countries but less common in poorer countries),8, 11 with less evidence on the benefits of other forms of physical activity such as during transportation,¹² housework, and occupational physical activity.¹³

Research in context

Evidence before this study

We searched the MEDLINE database for articles regarding the role of physical activity and exercise on mortality and cardiovascular disease across countries at various economic levels. We used the terms “physical activity”, “exercise”, “mortality”, “cardiovascular disease” in English but without date restrictions. We screened papers by title and abstract to identify full-text papers that were relevant to the study aims. We also screened citation lists from these full-text papers to identify other relevant research. The papers cited in this report were selected to be representative of the existing evidence base, and are not an exhaustive list of relevant research.

Added value of this study

Studies investigating the role of physical activity in preventing death from cardiovascular disease have been primarily from high-income countries, and focused on recreational or leisure time physical activity. In low-income and middle-income countries, physical activity is predominantly from non-recreational activities such as transportation, occupation, and housework, and therefore findings in high-income countries might not apply to other countries. A few studies have reported on the role of physical activity in low-income and middle-income countries, but these were cross-sectional or used inconsistent methods and are therefore not robust. Our investigation looks at the relationship between recreational and non-recreational physical activity and incident events in countries from all regions of the world.

Implications of all the available evidence

Physical activity is associated with reduced risk of mortality and incident cardiovascular disease in all regions of the world. The greatest reductions occurred at the lowest and continued to be present at very high levels of physical activity with no indication of a ceiling effect. In addition, both recreational and non-recreational physical activity were associated with lower risks. Physical activity is a low-cost approach to reducing deaths and cardiovascular disease that is applicable globally with potential large impact.

In the Prospective Urban Rural Epidemiologic (PURE) study done in 17 countries of various income levels, we examined whether physical activity is associated with lower risk of mortality and CVD in countries at varying economic levels and whether these associations differ by type of physical activity.