“…Referring to previous studies (2,22,31,37,(42)(43)(44)(45)(46), covariables in this association included age, household register (rural or urban), home address (East, Middle, or West China, according to the National Development and Reform Commission), employment (employed or unemployed), marriage (married or unmarried), educational attainment, smoking (whether one smoked in the past month), drinking (whether one drank three times a week or more in the past month), and family size (the logarithm of the total number of people in a household). Meanwhile, we divided the samples into subgroups A (married and unmarried), B (junior college and above and below junior college), and C (urban and rural) according to marital status, education level, and household registration.…”