Associations of Family Income and Healthy Lifestyle with All-cause Mortality

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.