Social determinants of health, health disparities, and adiposity

Abstract

Social determinants of health (SDoH), or the socioeconomic, environmental, and psychosocial conditions in which individuals spend their daily lives, substantially influence obesity as a cardiovascular disease (CVD) risk factor. The coronavirus disease 2019 (COVID-19) pandemic highlighted the converging epidemics of obesity, CVD, and social inequities globally. Obesity and CVD serve as independent risk factors for COVID-19 severity and lower-resourced populations most impacted by adverse SDoH have the highest COVID-19 mortality rates. Better understanding the interplay between social and biologic factors that contribute to obesity-related CVD disparities are important to equitably address obesity across populations. Despite efforts to investigate SDoH and their biologic effects as drivers of health disparities, the connections between SDoH and obesity remain incompletely understood. This review aims to highlight the relationships between socioeconomic, environmental, and psychosocial factors and obesity. We also present potential biologic factors that may play a role in the biology of adversity, or link SDoH to adiposity and poor adipo-cardiology outcomes. Finally, we provide evidence for multi-level obesity interventions targeting multiple aspects of SDoH. Throughout, we emphasize areas for future research to tailor health equity-promoting interventions across populations to reduce obesity and obesity-related CVD disparities.

Introduction

Social determinants of health (SDoH), or the socioeconomic, environmental, and psychosocial conditions in which individuals spend their daily lives, have clear and significant effects on obesity as a cardiovascular (CV) disease (CVD) risk factor.¹ Obesity is a complex, multifactorial disease defined by the World Health Organization as abnormal or excessive accumulation of adipose tissue that negatively impacts overall health.² Obesity is associated with the development of CVD at younger ages with poorer long-term outcomes.³ From a clinical standpoint, obesity is commonly defined by a body mass index (BMI) at or above 30 kg/m², with a BMI between 30 and 34.9 kg/m² defining Class 1, 35 and 39.9 kg/m² indicating Class 2, and 40 kg/m² or higher categorized as Class 3 obesity.³ However, BMI has significant limitations as it does not consider adipose tissue distribution and varies in predictive accuracy of adiposity and CVD risk by age, sex, race, and ethnicity.³ Waist circumference and waist-to-hip ratio are accessible, more precise measures of visceral adiposity and may more accurately predict CVD risk.³

Independent of its definition, obesity prevalence has steadily increased in the U.S. and globally over the last 40 years, with the National Health and Nutrition Examination Survey (NHANES) estimating obesity among 41.9% of adults aged 20 and over based on pre-pandemic data from 2017 to 2020.^4,5 There are notable racial, ethnic, and socioeconomic disparities in obesity; increasing obesity prevalence and disparities also persist in pediatric populations.⁴ The coronavirus disease 2019 (COVID-19) pandemic highlighted the converging epidemics of obesity, CVD, and social inequities globally, with obesity and CVD being independent risk factors for COVID-19 severity and lower-resourced populations most impacted by adverse SDoH having the highest COVID-19 mortality rates.⁶ These patterns underscore the importance of understanding the impact of SDoH on obesity as a CVD risk factor and addressing these exposures over the life course given that weight status in childhood is predictive of having overweight or obesity in adulthood.⁷ With half of the U.S. population projected to have obesity by 2030,⁸ it is especially critical to understand the relationship between SDoH and adiposity-related physiologic pathways to inform the design and implementation of multi-level obesity interventions that target both the individual and related adverse SDoH in at-risk communities. Moreover, understanding the interplay between social and biologic factors in adiposity can aid in clinical practice, particularly in obesity treatment and primary CVD prevention.

In our previous work, we presented a health equity-focused SDoH framework (Fig. 1) that outlined elements of structural health determinants and antecedents of social position which shape lived experiences, define disparities in access to health-promoting resources, and promote differences in CV health behaviors to subsequently produce disparate CVD outcomes.¹ Further, we discussed the biology of adversity, highlighting the possible biologic pathways through which structural and intermediate social determinants of CVD get under the skin to influence CV health. In this review, we focus on the social determinants of adiposity; that is, we describe the socioeconomic, environmental, and psychosocial conditions that facilitate the development of obesity. Additionally, we summarize physiologic mechanisms that may link SDoH with adiposity to highlight the biologic consequences of adverse social, environmental, and psychosocial factors in obesity. Finally, we present implications for practice and future research to mitigate obesity and adverse adiposity-related CVD outcomes.