Risk factor contributions to socioeconomic inequality in cardiovascular risk in the Philippines: a cross-sectional study of nationally representative survey data

Brindley et al. BMC Public Health (2023) 23:689 https://doi.org/10.1186/s12889-023-15517-x BMC Public Health Open Access RESEARCH Risk factor contributions to socioeconomic inequality in cardiovascular risk in the Philippines: a cross-sectional study of nationally representative survey data Callum Brindley1,2* , Tom Van Ourti1,2,3,4 , Joseph Capuno5 , Aleli Kraft5 , Jenny Kudymowa3,6 and Owen O’Donnell1,2,3,4,7 Abstract Background Primary prevention of cardiovascular diseases (CVD) increasingly relies on monitoring global CVD risk scores. Lack of evidence on socioeconomic inequality in these scores and the contributions that specific risk factors make to this inequality impedes effective targeting of CVD prevention. We aimed to address this evidence gap by measuring and decomposing socioeconomic inequality in CVD risk in the Philippines. Methods We used data on 8462 individuals aged 40–74 years from the Philippines National Nutrition Survey and the laboratory-based Globorisk equation to predict 10-year risk of a CVD event from sex, age, systolic blood pressure, total cholesterol, high blood glucose, and smoking. We used a household wealth index to proxy socioeconomic status and measured socioeconomic inequality with a concentration index that we decomposed into contributions of the risk factors used to predict CVD risk. We measured socioeconomic inequalities in these risk factors and decomposed them into contributions of more distal risk factors: body mass index, fat share of energy intake, low physical activity, and drinking alcohol. We stratified by sex. Results Wealthier individuals, particularly males, had greater exposure to all risk factors, with the exception of smoking, and had higher CVD risks. Total cholesterol and high blood glucose accounted for 58% and 34%, respectively, of the socioeconomic inequality in CVD risk among males. For females, the respective estimates were 63% and 69%. Systolic blood pressure accounted for 26% of the higher CVD risk of wealthier males but did not contribute to inequality among females. If smoking prevalence had not been higher among poorer individuals, then the inequality in CVD risk would have been 35% higher for males and 75% higher for females. Among distal risk factors, body mass index and fat intake contributed most to inequalities in total cholesterol, high blood sugar, and, for males, systolic blood pressure. *Correspondence: Callum Brindley Full list of author information is available at the end of the article © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Brindley et al. BMC Public Health (2023) 23:689 Page 2 of 11 Conclusions Wealthier Filipinos have higher predicted CVD risks and greater exposure to all risk factors, except smoking. There is need for a nuanced approach to CVD prevention that targets anti-smoking programmes on the poorer population while targeting diet and exercise interventions on the wealthier. Key message • Evidence on risk factor contributions to socioeconomic inequalities in cardiovascular disease (CVD) risk is needed to target prevention programmes and meet the SDG target of a one third reduction in premature noncommunicable disease mortality by 2030. • In the Philippines, wealthier individuals have higher predicted CVD risks and greater exposure to all risk factors, except smoking. • Total Cholesterol (TC) and High Blood Glucose (HBG) contribute most to the higher CVD risks of wealthier Filipinos. • Wealth inequalities in TC and HBG, and (for males) in systolic blood pressure, are mostly explained by differences in body mass index and fat share of energy intake, and not by differences in physical exercise. • To maximise impact, CVD prevention in the Philippines should target diet programmes on wealthier groups and smoking programmes on poorer groups. Keywords Cardiovascular disease, Risk factors, Blood pressure, Blood glucose, Cholesterol, Smoking, Socioeconomic, Inequality, Decomposition, Philippines Introduction Low-cost primary prevention interventions can reduce the large and accumulating burden of cardiovascular disease (CVD) in low- and middle-income countries (LMICs). [1–3] Realisation of this potential requires targeting high risks among people who are asymptomatic, have not previously experienced a CVD event, and yet account for around three fifths of all CVD deaths [4]. There has been a shift in primary prevention away from management of separate CVD risk factors, such as hypertension, dyslipidemia, high blood glucose, and smoking, to the assessment and control of CVD risk predicted from these factors [3, 5–9]. And yet there is no evidence from LMICs, or even from high-income countries, [10] on socioeconomic inequality in predicted CVD risk broken down into the contributions of separate risk factors. This impedes effective implementation of a risk-based primary prevention strategy because information is lacking to plan the targeted distribution of treatments that meet the needs of high-risk groups. The relatively few LMIC studies that have examined associations between CVD risk and markers of socioeconomic status (SES) have delivered mixed evidence on the direction of the gradient [11–15]. More plentiful LMIC evidence on socioeconomic inequalities in separate CVD risk factors tends to show that higher SES groups are more exposed to most risk factors, [11, 13, 16–26] although this is not a universal finding [15, 27–29]. The opposite socioeconomic gradient is usually found for smoking tobacco [15, 16, 23, 24, 26, 30] and insufficient consumption of fruit and vegetables [16, 23, 30]. In the Philippines, the burden of CVD – measured by age-standardised disability-adjusted life years – has increased relatively from 41% below the average for Southeast Asia in 1990 to 10% above that average in 2019. [31] If this trend continues, the Philippines will not reach the Sustainable Development Goal (SDG) target of a one-third reduction in premature mortality from non (...truncated)