Methods: Data were obtained from four nationally representative data sources from the US: The National Health Interview Survey [NHIS] (2015-2018); the National Health and Nutrition Examination Survey [NHANES] (2017-2020); the Behavioral Risk Factor Surveillance System [BRFSS] (2016-2020); and the Health & Retirement Study [HRS] (2016). Respondent-rated poor health and obesity were selected as the health indicators of interest. Socioeconomic factors included percentages of the federal poverty level and years of educational attainment. We conducted a logistic regression analysis to calculate adjusted prevalence rates of respondent-rated poor health and obesity by income and education categories after controlling for sociodemographic characteristics (i.e., age, sex, and race/ethnicity). A complex sampling design was applied in all analyses.
Results: Prevalence rates across racial/ethnic groups and age groups demonstrated clear and consistent socioeconomic gradients in respondent-rated poor health. Prevalence rates of respondent-rated poor health were the highest among those in the lowest income and education categories, and the rates decreased as income and education levels increased. On the other hand, there were less evident socioeconomic differences in obesity rates across all data sources, racial/ethnic groups, and age groups. For children, rates of obesity appeared to decrease as income and education went up, but with less apparent socioeconomic patterns when using the NHANES data. In middle-aged and older adult samples, education gradient patterns were observed in the NHIS, the BRFSS, and the HRS data, but not in the NHANES data, and the income gradient in obesity was less apparent across data sources. Overall, the NHANES data tends to produce higher prevalence rates of respondent-rated poor health and obesity across all groups and socioeconomic factors compared to three other data sources.
Conclusions/Implications: Our results confirmed earlier evidence indicating socioeconomic disparities in respondent-rated poor health across all age and race/ethnicity groups by using several nationally representative datasets. The results suggest an urgent need for action to alleviate pervasive health disparities by socioeconomic status. Further research is needed to elaborate on the underlying mechanisms of different socioeconomic patterns in various health indicators. Future research is also needed to investigate potentially modifiable factors underlying socioeconomic disparities in health, which may help design targeted health promotion programs.