Associations of family income and healthy lifestyle with all-cause mortality

Abstract

Background There is a lack of evidence on whether combined lifestyle factors mediate the association between family income and all-cause mortality, as well as the joint relations between family income and lifestyle factors with mortality. Methods Using data on family income and lifestyle factors of participants in the US National Health Interview Survey 2016–2018, we performed multivariable logistic regression models to estimate the odds ratios (ORs) and 95% confidence intervals (CI) for the association of all-cause mortality with said data. Results We included 73 729 participants with a mean age of 47.1 years (standard deviation (SD) = 18.0), 51% of whom were women and 65% of whom were non-Hispanic Whites. There were 2284 deaths documented. After multivariable adjustment, middle-income participants had an OR of 0.73 (95% CI = 0.61–0.88) for mortality, while high-income participants had an OR of 0.47 (95% CI = 0.37–0.60) compared with low-income participants. We found that lower all-cause mortality was related to higher lifestyle scores. Adults from high-income families with lifestyle scores of 3 and 4 had an OR for mortality of 0.44 (95% CI = 0.30–0.65) compared to those from low-income families and lifestyle scores of 0 or 1. When comparing those in highest vs lowest income groups in the mediation analysis, 9.8% (95% CI = 7.4–13.0) of the relation for all-cause mortality was mediated by lifestyles. Adults from high-income families with lifestyle scores of 3 or 4 had an OR of 0.23 (95% CI = 0.17–0.33) for mortality compared with those from low-income families and lifestyle scores of 0 or 1. Conclusions A lower risk of all-cause mortality was linked to higher family income and healthier lifestyles. Furthermore, lifestyle factors mediated a small proportion of the association between family income and mortality among US adults. Economic disparity in health may not be eliminated by changing only one’s lifestyle. Therefore, besides promoting a healthy lifestyle, we should stress how family income inequality affects health outcomes.