Annika Rosengren, ProfMD, Andrew Smyth, MD, Sumathy Rangarajan, MSc, Chinthanie Ramasundarahettige, MSc, Shrikant I Bangdiwala, PhD, Khalid F AlHabib, ProfMD, Alvaro Avezum, ProfMD, Kristina Bengtsson Boström, ProfMD, Jephat Chifamba, ProfDPhil, Sadi Gulec, MD, Rajeev Gupta, ProfPhD, Ehi U Igumbor, PhD, Romaina Iqbal, PhD, Norhassim Ismail, ProfMD, Philip Joseph, MD, Manmeet Kaur, MD, Rasha Khatib, PhD, Iolanthé M Kruger, PhD, Pablo Lamelas, MD, Fernando Lanas, ProfMD, Scott A Lear, ProfPhD, Wei Li, ProfPhD, Chuangshi Wang, MSc, Deren Quiang, MSc, Yang Wang, MSc, Patricio Lopez-Jaramillo, ProfMD, Noushin Mohammadifard, PhD, Viswanathan Mohan, ProfMD, Prem K Mony, MD, Paul Poirier, ProfMD, Sarojiniamma Srilatha, MD, Andrzej Szuba, ProfMD, Koon Teo, ProfPhD, Andreas Wielgosz, ProfMD, Karen E Yeates, MD, Khalid Yusoff, ProfMD, Rita Yusuf, ProfPhD, Afzalhusein H Yusufali, MD, Marjan W Attaei, PhD, Martin McKee, ProfDSc, and Salim Yusuf, ProfDPhil
Summary: Background: Socioeconomic status is associated with differences in risk factors for cardiovascular disease incidence and outcomes, including mortality. However, it is unclear whether the associations between cardiovascular disease and common measures of socioeconomic status—wealth and education—differ among high-income, middle-income, and low-income countries, and, if so, why these differences exist. We explored the association between education and household wealth and cardiovascular disease and mortality to assess which marker is the stronger predictor of outcomes, and examined whether any differences in cardiovascular disease by socioeconomic status parallel differences in risk factor levels or differences in management. Methods: In this large-scale prospective cohort study, we recruited adults aged between 35 years and 70 years from 367 urban and 302 rural communities in 20 countries. We collected data on families and households in two questionnaires, and data on cardiovascular risk factors in a third questionnaire, which was supplemented with physical examination. We assessed socioeconomic status using education and a household wealth index. Education was categorised as no or primary school education only, secondary school education, or higher education, defined as completion of trade school, college, or university. Household wealth, calculated at the household level and with household data, was defined by an index on the basis of ownership of assets and housing characteristics. Primary outcomes were major cardiovascular disease (a composite of cardiovascular deaths, strokes, myocardial infarction, and heart failure), cardiovascular mortality, and all-cause mortality. Information on specific events was obtained from participants or their family. Findings: Recruitment to the study began on Jan 12, 2001, with most participants enrolled between Jan 6, 2005, and Dec 4, 2014. 160 299 (87·9%) of 182 375 participants with baseline data had available follow-up event data and were eligible for inclusion. After exclusion of 6130 (3·8%) participants without complete baseline or follow-up data, 154 169 individuals remained for analysis, from five low-income, 11 middle-income, and four high-income countries. Participants were followed-up for a mean of 7·5 years. Major cardiovascular events were more common among those with low levels of education in all types of country studied, but much more so in low-income countries. After adjustment for wealth and other factors, the HR (low level of education vs high level of education) was 1·23 (95% CI 0·96–1·58) for high-income countries, 1·59 (1·42–1·78) in middle-income countries, and 2·23 (1·79–2·77) in low-income countries (pinteraction