Multiple job holding, working hours, and hypertension by race/ethnicity and sex.

The number of Americans with multiple jobs is increasing and multiple jobholders work more hours per week. However, the associations between multiple jobholding and hypertension are unknown. The aim of this study was to examine the associations of multiple jobholding with hypertension and determine whether weekly working hours moderated this association. Data from the 2015 National Health Interview Survey on adults (age ≥18 years) were used and included participants who self-identified as non-Hispanic Asian, non-Hispanic Black, Hispanic, or non-Hispanic White in the U.S. (n = 16,926), The associations of multiple jobholding with self-reported hypertension by sex were assessed using modified Poisson regressions. Both the number of working hours per week and race/ethnicity were assessed as moderators using multiplicative interaction terms. Multiple jobholding was not associated with hypertension among women. However, there was a significant three-way interaction such that multiple jobholding was associated with hypertension among non-Hispanic Black men who worked ≥55 hours per week (relative risk = 1.02, 95% confidence interval = 1.01-1.05). The results suggest that the associations between multiple jobholding, number of working hours, and hypertension should be examined at the intersection of race/ethnicity and sex. Future studies should further characterize multiple jobholding and hypertension among non-Hispanic Black men.