The interaction between district-level development and individual-level socioeconomic gradients of cardiovascular disease risk factors in India: A cross-sectional study of 2.4 million adults

A Global Perspective on Socioeconomic Determinants of Cardiovascular Health

Cardiovascular disease (CVD) is the leading cause of mortality in the world. From 2005 to 2008, the World Health Organization (WHO) planned an initiative to reduce the mortality rate of CVD by 2030 by addressing health, finance, transport, education, and agriculture in these communities. Plans were underway by many countries to meet the goals of the WHO initiative. However, in 2020, the COVID-19 pandemic derailed these goals, and many health systems suffered as the world battled the viral pandemic. The pandemic made health inequities even more prominent and necessitated a different approach to understanding and improving the socioeconomic determinants of health (SDOH). WHO initiated a special initiative to improve SDOH globally. This paper is an update on what other regions across the globe are doing to decrease, more specifically, the impact of socioeconomic determinants of cardiovascular health. Our review highlights how countries and regions such as Canada, the United States, India, Southeast Asia, the Middle East, and Africa are uniquely affected by various socioeconomic factors and how these countries are attempting to counter these obstacles by creating policies and protocols to facilitate an infrastructure that promotes screening and treatment of CVD. Ultimately, interventions directed toward populations that have been economically and socially marginalized may aid in reducing the disease and financial burden associated with CVD.

Association of socioeconomic inequality in cardiovascular disease risk with economic development across 57 low- and middle-income countries: Cross-sectional analysis of nationally representative individual-level data

BACKGROUND

According to epidemiological transition theory, cardiovascular disease (CVD) risk shifts down the socioeconomic distribution with economic development.

METHODS

We tested this hypothesis using nationally representative data on 88,559 individuals aged 40-80 years from 57 low- and middle-income countries (LMICs). We used measured risk factors to estimate the 10-year probability of a CVD event (CVD risk) and proxied socioeconomic status (SES) by years of education. We used a concentration index to measure socioeconomic inequality in CVD risk and decomposed it into risk factor contributions. We estimated associations CVD risk and inequality in that risk with gross national income (GNI) per capita (pc).

RESULTS

We estimated that a 1% higher GNI pc was associated with higher mean CVD risk of 0.0265 percentage points (pp) (95% CI: 0.0169-0.0361) among females and 0.0150 pp (0.0082-0.0219) among males. All risk factors, except systolic blood pressure (SBP) and smoking among females, were positively associated with GNI pc. In most countries, lower SES was associated with higher CVD risk. Age, SBP, diabetes (females only) and smoking (males particularly) contributed most to this inequality, while inequality in total cholesterol was mostly in the opposite direction. Lower SES individuals tended to have relatively higher CVD risk at higher GNI pc, particularly among females. This was due to differences in the distributions of SBP and, for females, age and diabetes.

CONCLUSIONS

Economic development was associated with higher and more unequal CVD risk, which may warrant shifting targeting of CVD primary prevention to socially disadvantaged groups.

Socioeconomic inequalities in adverse pregnancy outcomes in India: 2004-2019

Although India has made substantial improvements in public health, it accounted for one-fifth of global maternal and neonatal deaths in 2015. Stillbirth, abortion, and miscarriage contribute to maternal and infant morbidity and mortality. There are known socioeconomic inequalities in adverse pregnancy outcomes. This study estimated changes in socioeconomic inequalities in rates of stillbirth, abortion, and miscarriage in India across 15 years. We combined data from three nationally representative health surveys. Absolute inequalities were estimated using the slope index of inequality and risk differences, and relative inequalities were estimated using the relative index of inequalities and risk ratios. We used household wealth, maternal education, and Scheduled Caste and Scheduled Tribe membership as socioeconomic indicators. We observed persistent socioeconomic inequalities in abortion and stillbirth from rates of 2004-2019. Women at the top of the wealth distribution reported between 2 and 5 fewer stillbirths per 1,000 pregnancies over the study time period compared to women at the bottom of the wealth distribution. Women who completed primary school, and those at the top of the household wealth distribution, had, over the study period, 5 and 20 additional abortions per 1,000 pregnancies respectively compared to women who did not complete primary school and those at the bottom of the wealth distribution. Women belonging to a Scheduled Caste or Scheduled Tribe had 5 fewer abortions per 1,000 pregnancies compared to other women, although these inequalities diminished by the end of the study period. There was less consistent evidence for socioeconomic inequalities in miscarriage, which increased for all groups over the study period. Despite targeted investments by the Government of India to improve access to health services for socioeconomically disadvantaged groups, disparities in pregnancy outcomes persist.

"Mother's milk": Is there a social reversal in breastfeeding practices along with economic development?

Previous studies suggest that macro- and micro-level factors jointly influence breastfeeding (BF) practices, but empirical evidence on the dynamics of such interactions along with the process of a country's economic development remains limited. Based on 42 Demographic Health Surveys (DHS) conducted in 15 Asian countries with a large time window (1990-2017), we thus test the existence of a reversal in the association between household wealth and BF practices throughout the development process. Four BF indicators (early initiation of BF, exclusive BF, continued BF at one year and two years) are examined, along with a standardized asset-based household wealth index allowing for cross-wave and cross-country comparisons. To highlight the dynamics of the wealth-BF association, we carry out econometric estimations, including interaction terms between household wealth and the country's level of economic development (low, medium, and high) or time. Instrumental variable estimations are also performed to limit suspected endogeneity issues. Our results confirm a transition in the wealth gradient of exclusive BF and continued BF in Asian countries. More precisely, while these practices are pro-poor in the poorest countries of the sample, they progressively spread to wealthier households along with the level of economic development. For exclusive BF, this transition has resulted in a reversal of the wealth gradient at the end of the period (i.e., exclusive BF prevalence among the rich overpassing that of the poor). We fail, however, to observe this kind of transition for early initiation of BF, this practice remaining pro-poor, whatever the level of economic development. To sum up, our results provide robust evidence of a transition in the wealth gradient of some BF practices along with economic development and time, and thus largely echo the literature exploring the social reversal hypothesis in the case of non-communicable diseases.

How economic development affects healthcare access for people with disabilities: A multilevel study in China

Meeting the healthcare needs of people with disabilities is an important challenge in achieving the central promise of "leave no one behind" during the Sustainable Development Goals era. In this study, we describe the accessibility of healthcare for people living with disabilities, as well as the potential influences of individuals' socioeconomic status and regional economic development. Our data covered 324 prefectural cities in China in 2019 and captured the access to healthcare services for people with disabilities. First, we used linear probability regression models to investigate the association between individual socioeconomic status, including residence, poverty status, education, and healthcare access. Second, we conducted an ecological analysis to test the association between prefectural economic indicators, including GDP (gross domestic product) per capita, urbanization ratio, average years of education, Engel's coefficient, and the overall prevalence of access to healthcare for people with disabilities within prefectures. Third, we used multilevel regression models to explore the association between the individual's socio-economic status, prefectural economic indicators, and access to healthcare at the individual level for people with disabilities. The results showed, first, that higher individual socioeconomic status (urban residence or higher educational level) was associated with better access to healthcare for people with disabilities. Second, regional economic indicators were positively associated with access to healthcare at the aggregate and individual levels. This study suggests that local governments, particularly in low- and middle-income countries, should promote economic development and conduct poverty alleviation policies to improve healthcare access for disadvantaged groups.

Hypertension care cascades and reducing inequities in cardiovascular disease in low- and middle-income countries

Improving hypertension control in low- and middle-income countries has uncertain implications across socioeconomic groups. In this study, we simulated improvements in the hypertension care cascade and evaluated the distributional benefits across wealth quintiles in 44 low- and middle-income countries using individual-level data from nationally representative, cross-sectional surveys. We raised diagnosis (diagnosis scenario) and treatment (treatment scenario) levels for all wealth quintiles to match the best-performing country quintile and estimated the change in 10-year cardiovascular disease (CVD) risk of individuals initiated on treatment. We observed greater health benefits among bottom wealth quintiles in middle-income countries and in countries with larger baseline disparities in hypertension management. Lower-middle-income countries would see the greatest absolute benefits among the bottom quintiles under the treatment scenario (29.1 CVD cases averted per 1,000 people living with hypertension in the bottom quintile (Q1) versus 17.2 in the top quintile (Q5)), and the proportion of total CVD cases averted would be largest among the lowest quintiles in upper-middle-income countries under both diagnosis (32.0% of averted cases in Q1 versus 11.9% in Q5) and treatment (29.7% of averted cases in Q1 versus 14.0% in Q5) scenarios. Targeted improvements in hypertension diagnosis and treatment could substantially reduce socioeconomic-based inequalities in CVD burden in low- and middle-income countries.

Metabolic non-communicable disease health report of India: the ICMR-INDIAB national cross-sectional study (ICMR-INDIAB-17)

BACKGROUND

Non-communicable disease (NCD) rates are rapidly increasing in India with wide regional variations. We aimed to quantify the prevalence of metabolic NCDs in India and analyse interstate and inter-regional variations.

METHODS

The Indian Council of Medical Research-India Diabetes (ICMR-INDIAB) study, a cross-sectional population-based survey, assessed a representative sample of individuals aged 20 years and older drawn from urban and rural areas of 31 states, union territories, and the National Capital Territory of India. We conducted the survey in multiple phases with a stratified multistage sampling design, using three-level stratification based on geography, population size, and socioeconomic status of each state. Diabetes and prediabetes were diagnosed using the WHO criteria, hypertension using the Eighth Joint National Committee guidelines, obesity (generalised and abdominal) using the WHO Asia Pacific guidelines, and dyslipidaemia using the National Cholesterol Education Program-Adult Treatment Panel III guidelines.

FINDINGS

A total of 113 043 individuals (79 506 from rural areas and 33 537 from urban areas) participated in the ICMR-INDIAB study between Oct 18, 2008 and Dec 17, 2020. The overall weighted prevalence of diabetes was 11·4% (95% CI 10·2-12·5; 10 151 of 107 119 individuals), prediabetes 15·3% (13·9-16·6; 15 496 of 107 119 individuals), hypertension 35·5% (33·8-37·3; 35 172 of 111 439 individuals), generalised obesity 28·6% (26·9-30·3; 29 861 of 110 368 individuals), abdominal obesity 39·5% (37·7-41·4; 40 121 of 108 665 individuals), and dyslipidaemia 81·2% (77·9-84·5; 14 895 of 18 492 of 25 647). All metabolic NCDs except prediabetes were more frequent in urban than rural areas. In many states with a lower human development index, the ratio of diabetes to prediabetes was less than 1.

INTERPRETATION

The prevalence of diabetes and other metabolic NCDs in India is considerably higher than previously estimated. While the diabetes epidemic is stabilising in the more developed states of the country, it is still increasing in most other states. Thus, there are serious implications for the nation, warranting urgent state-specific policies and interventions to arrest the rapidly rising epidemic of metabolic NCDs in India.

FUNDING

Indian Council of Medical Research and Department of Health Research, Ministry of Health and Family Welfare, Government of India.

Changing socioeconomic and geographic gradients in cardiovascular disease risk factors among Indians aged 15-49 years - evidence from nationally representative household surveys

Background

Cardiovascular diseases (CVDs) are the leading cause of death in most low- and middle-income countries (LMICs). CVDs and their metabolic risk factors have historically been concentrated among urban residents with higher socioeconomic status (SES) in LMICs such as India. However, as India develops, it is unclear whether these socioeconomic and geographic gradients will persist or change. Understanding these social dynamics in CVD risk is essential for mitigating the rising burden of CVDs and to reach those with the greatest needs.

Methods

Using nationally representative data with biomarker measurements from the fourth (2015-16) and fifth (2019-21) Indian National Family and Health Surveys, we investigated trends in the prevalence of four CVD risk factors: smoking (self-reported), unhealthy weight (BMI ≥25 kgm2), diabetes (random plasma glucose concentration ≥200 mg/dL or self-reported diabetes), and hypertension (one of: average systolic blood pressure ≥140 mmHg, average diastolic blood pressure ≥90 mmHg, self-reported past diagnosis, or self-reported current antihypertensive medication use) among adults aged 15-49 years. We first described changes at the national level and then trends stratified by place of residence (urban versus rural), geographic region (northern, northeastern, central, eastern, western, southern), regional level of development (Empowered Action Group member state or not), and two measures of socioeconomic status: level of education (no education, primary incomplete, primary complete, secondary incomplete, secondary complete, higher) and wealth (quintiles).

Findings

Unhealthy weight increased among all social and geographic groups but both the absolute and the relative changes were substantially higher among people with low SES (as measured by education or wealth) and in rural areas. For diabetes and hypertension, the prevalence increased for those from disadvantaged groups while staying constant or even decreasing among the wealthier and more educated. In contrast, smoking consumption declined for all social and geographic groups.

Interpretation

In 2015-16, CVD risk factors were higher among more advantaged subpopulations in India. However, between 2015-16 and 2019-21, the prevalence of these risk factors grew more rapidly for less wealthy and less educated subpopulations and those living in rural areas. These trends have resulted in CVD risk becoming far more widespread throughout the population; CVD can no longer be characterized as a wealthy urban phenomenon.

Funding

This work was supported by the Alexander von Humboldt Foundation (grant received by NS); the Stanford Diabetes Research Center [grant received by PG] and the Chan Zuckerberg Biohub [grant received by PG].

Re-examining the reversal hypothesis: A nationwide population-based study of the association between socioeconomic status, and NCDs and risk factors in China

Background

According to the reversal hypothesis, as a country's economic and social development progresses, the burden of NCDs and risk factors shifts from rich to poor. The aim of this research is to examine the reversal hypothesis in the Chinese setting.

Methods

Using data from the China Health and Retirement Longitudinal Study (CHARLS) in 2015, we explored whether the reversal hypothesis applies at the subnational level. Participants aged 45 years and older in 2015 were included. We examined five risk factors (smoking, heavy drinking, physical inactivity, overweight, and obesity) and three objectively measured NCDs (diabetes, hypertension, dyslipidemia). Binary logistic regressions were performed to examine outcomes across people of differing SES in provincial level, in urban and rural areas, and across generations.

Results

Nationally, SES is positively associated with heavy drinking, obesity, diabetes and dyslipidemia, whereas it is negatively associated with physical inactivity. The association between SES and smoking and hypertension was not statistically significant. Except in the cases of diabetes and dyslipidemia, we found that risk factors of all kinds were more concentrated among richer people in rural than in urban areas. Across provinces with increasing GDP per capita, a downward trend in risk factors among those with high SES compared to those with low SES could be interpreted, while the opposite trend could be interpreted with respect to the metabolic syndrome conditions. Obesity and overweight exhibited slight downward trends (in line with those for risk factors) and upward trends (in line with those for metabolic syndrome conditions), respectively.

Conclusion

We conclude that China is at a relatively early stage of 'reversal', visible with respect to risk factors. If these patterns persist over time, the trend will likely feed through to metabolic disorders which will increasingly become diseases of the poor.

The Association of Socioeconomic Status With Hypertension in 76 Low- and Middle-Income Countries

BACKGROUND

Effective equity-focused health policy for hypertension in low- and middle-income countries (LMICs) requires an understanding of the condition's current socioeconomic gradients and how these are likely to change in the future as countries develop economically.

OBJECTIVES

This cross-sectional study aimed to determine how hypertension prevalence in LMICs varies by individuals' education and household wealth, and how these socioeconomic gradients in hypertension prevalence are associated with a country's gross domestic product (GDP) per capita.

METHODS

We pooled nationally representative household survey data from 76 LMICs. We disaggregated hypertension prevalence by education and household wealth quintile, and used regression analyses to adjust for age and sex.

RESULTS

We included 1,211,386 participants in the analysis. Pooling across all countries, hypertension prevalence tended to be similar between education groups and household wealth quintiles. The only world region with a clear positive association of hypertension with education or household wealth quintile was Southeast Asia. Countries with a lower GDP per capita had, on average, a more positive association of hypertension with education and household wealth quintile than countries with a higher GDP per capita, especially in rural areas and among men.

CONCLUSIONS

Differences in hypertension prevalence between socioeconomic groups were generally small, with even the least educated and least wealthy groups having a substantial hypertension prevalence. Our cross-sectional interaction analyses of GDP per capita with the socioeconomic gradients of hypertension suggest that hypertension may increasingly affect adults in the lowest socioeconomic groups as LMICs develop economically.

Educational inequalities in obesity: a multilevel analysis of survey data from cities in Latin America

OBJECTIVE

Using newly harmonised individual-level data on health and socio-economic environments in Latin American cities (from the Salud Urbana en América Latina (SALURBAL) study), we assessed the association between obesity and education levels and explored potential effect modification of this association by city-level socio-economic development.

DESIGN

This cross-sectional study used survey data collected between 2002 and 2017. Absolute and relative educational inequalities in obesity (BMI ≥ 30 kg/m2, derived from measured weight and height) were calculated first. Then, a two-level mixed-effects logistic regression was run to test for effect modification of the education-obesity association by city-level socio-economic development. All analyses were stratified by sex.

SETTING

One hundred seventy-six Latin American cities within eight countries (Brazil, Chile, Colombia, Costa Rica, El Salvador, Guatemala, Mexico and Peru).

PARTICIPANTS

53 186 adults aged >18 years old.

RESULTS

Among women, 25 % were living with obesity and obesity was negatively associated with educational level (higher education-lower obesity) and this pattern was consistent across city-level socio-economic development. Among men, 18 % were living with obesity and there was a positive association between education and obesity (higher education-higher obesity) for men living in cities with lower levels of development, whereas for those living in cities with higher levels of development, the pattern was inverted and university education was protective of obesity.

CONCLUSIONS

Among women, education was protective of obesity regardless, whereas among men, it was only protective in cities with higher levels of development. These divergent results suggest the need for sex- and city-specific interventions to reduce obesity prevalence and inequalities.

Patterns of multimorbidity in India: A nationally representative cross-sectional study of individuals aged 15 to 49 years

There is a dearth of evidence on the epidemiology of multimorbidity in low- and middle-income countries. This study aimed to determine the prevalence of multimorbidity in India and its variation among states and population groups. We analyzed data from a nationally representative household survey conducted in 2015-2016 among individuals aged 15 to 49 years. Multimorbidity was defined as having two or more conditions out of five common chronic morbidities in India: anemia, asthma, diabetes, hypertension, and obesity. We disaggregated multimorbidity prevalence by condition, state, rural versus urban areas, district-level wealth, and individual-level sociodemographic characteristics. 712,822 individuals were included in the analysis. The prevalence of multimorbidity was 7·2% (95% CI, 7·1% - 7·4%), and was higher in urban (9·7% [95% CI, 9·4% - 10·1%]) than in rural (5·8% [95% CI, 5·7% - 6·0%]) areas. The three most prevalent morbidity combinations were hypertension with obesity (2·9% [95% CI, 2·8% - 3·1%]), hypertension with anemia (2·2% [95% CI, 2·1%- 2·3%]), and obesity with anemia (1·2% [95% CI, 1·1%- 1·2%]). The age-standardized multimorbidity prevalence varied from 3·4% (95% CI: 3·0% - 3·8%) in Chhattisgarh to 16·9% (95% CI: 13·2% - 21·5%) in Puducherry. Being a woman, being married, not currently smoking, greater household wealth, and living in urban areas were all associated with a higher risk of multimorbidity. Multimorbidity is common among young and middle-aged adults in India. This study can inform screening guidelines for chronic conditions and the targeting of relevant policies and interventions to those most in need.

Association of education level with diabetes prevalence in Latin American cities and its modification by city social environment

Background

Diabetes prevalence continues to increase in urban areas of low-income and middle-income countries (LMIC). Evidence from high-income countries suggests an inverse association between educational attainment and diabetes, but research in LMIC is limited. We investigated educational differences in diabetes prevalence across 232 Latin American (LA) cities, and the extent to which these inequities vary across countries/cities and are modified by city socioeconomic factors.

Methods

Using harmonised health survey and census data for 110 498 city dwellers from eight LA countries, we estimated the association between education and diabetes. We considered effect modification by city Social Environment Index (SEI) as a proxy for city-level development using multilevel models, considering heterogeneity by sex and country.

Results

In women, there was an inverse dose–response relationship between education and diabetes (OR: 0.80 per level increase in education, 95% CI 0.75 to 0.85), consistent across countries and not modified by SEI. In men, Argentina, Brazil, Colombia, Chile and Mexico showed an inverse association (pooled OR: 0.92; 95% CI 0.86 to 0.99). Peru, Panama and El Salvador showed a positive relationship (pooled OR 1.24; 95% CI 1.04 to 1.49). For men, these associations were further modified by city-SEI: in countries with an inverse association, it became stronger as city-SEI increased. In countries where the association was positive, it became weaker as city-SEI increased.

Conclusion

Social inequities in diabetes inequalities increase as cities develop. To achieve non-communicable disease-related sustainable development goals in LMIC, there is an urgent need to develop policies aimed at reducing these educational inequities.

Children's education and parental old-age health: Evidence from a population-based, nationally representative study in India

Previous research has documented intergenerational transmission of human capital from children to parents. Less is known, however, about heterogeneity in this 'upward transmission' in low-resource settings. We examine whether co-resident adult children's education is associated with improved health among older parents in India, using nationally representative data from the 2014 Indian National Sample Survey. Parents of children with tertiary education had a lower probability of reporting poor health than parents of children with less than primary education. The benefits of children's education persisted after controlling for economic factors, suggesting that non-pecuniary pathways-such as health knowledge or skills-may play an important role. The association was more pronounced among economically dependent parents and those living in the North and West regions. Taken together, our results point to a strong positive association between children's education and parental health, the role of non-pecuniary pathways, and the importance of subnational heterogeneity in India.

Nationally representative household survey data for studying the interaction between district-level development and individual-level socioeconomic gradients of cardiovascular disease risk factors in India

In this article, we describe the dataset used in our study entitled “The interaction between district-level development and individual-level socioeconomic gradients of cardiovascular disease risk factors in India: A cross-sectional study of 2.4 million adults”, recently published in Social Science & Medicine, and present supplementary analyses.

We used data from three different household surveys in India, which are representative at the district level. Specifically, we analyzed pooled data from the District-Level Household Survey 4 (DLHS-4) and the second update of the Annual Health Survey (AHS), and separately analyzed data from the National Family Health Survey (NFHS-4). The DLHS-4 and AHS sampled adults aged 18 years or older between 2012 and 2014, while the NFHS-4 sampled women aged 15–49 years and - in a subsample of 15% of households - men aged 15–54 years in 2015 and 2016.

The measures of individual-level socio-economic status that we used in both datasets were educational attainment and household wealth quintiles. The measures of district-level development, which we calculated from these data, were i) the percentage of participants living in an urban area, ii) female literacy rate, and iii) the district-level median of the continuous household wealth index. An additional measure of district-level development that we used was Gross Domestic Product per capita, which we obtained from the Planning Commission of the Government of India for 2004/2005.

Our outcome variables were diabetes, hypertension, obesity, and current smoking. The data were analyzed using both district-level regressions and multilevel modelling.