Authors : Annika Rosengren 1, Andrew Smyth 2, Sumathy Rangarajan 3, Chinthanie Ramasundarahettige 3, Shrikant I Bangdiwala 3, Khalid F AlHabib 4, Alvaro Avezum 5, Kristina Bengtsson Boström 6, Jephat Chifamba 7, Sadi Gulec 8, Rajeev Gupta 9, Ehi U Igumbor 10, Romaina Iqbal 11, Norhassim Ismail 12, Philip Joseph 3, Manmeet Kaur 13, Rasha Khatib 14, Iolanthé M Kruger 15, Pablo Lamelas 3, Fernando Lanas 16, Scott A Lear 17, Wei Li 18, Chuangshi Wang 18, Deren Quiang 19, Yang Wang 18, Patricio Lopez-Jaramillo 20, Noushin Mohammadifard 21, Viswanathan Mohan 22, Prem K Mony 23, Paul Poirier 24, Sarojiniamma Srilatha 25, Andrzej Szuba 26, Koon Teo 3, Andreas Wielgosz 27, Karen E Yeates 28, Khalid Yusoff 29, Rita Yusuf 30, Afzalhusein H Yusufali 31, Marjan W Attaei 3, Martin McKee 32, Salim Yusuf 3
Publication Year : Jun 2019
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<0>interaction<0>interaction<0>
Interpretation: Although people with a lower level of education in low-income and middle-income countries have higher incidence of and mortality from cardiovascular disease, they have better overall risk factor profiles. However, these individuals have markedly poorer health care. Policies to reduce health inequities globally must include strategies to overcome barriers to care, especially for those with lower levels of education.