Abstract
While alcohol's health effects are well documented, less is known about how health influences alcohol use and whether this varies by socioeconomic position (SEP). This study investigated the association between health-related quality of life (HRQoL), mental health, and alcohol use, and whether SEP moderates these associations. Baseline data from 7097 participants in the 2010 Stockholm Public Health Cohort were used. The exposures were HRQoL and mental health (good, moderate, poor); Outcomes (2014) were heavy episodic drinking (HED: ≥5 units/≥2 times/month) and heavy drinking (men: ≥21 units/week; women: ≥14 units/week). Logistic regression estimated odds ratios (OR), with interaction assessed using relative excess risk of interaction (RERI) and attributable proportion (AP). Joint exposure analyses used good health and high SEP as the reference group. Compared with good HRQoL, moderate (OR: 1.26, 95% CI: 1.02-1.56) and poor HRQoL (OR: 1.39, 95% CI: 1.08-1.78) were associated with higher odds of heavy drinking. Moderate HRQoL and low SEP had increased odds of HED (OR: 1.48, 95% CI: 1.02-2.15) and heavy drinking (OR: 1.62, 95% CI: 1.01-2.60), with evidence of additive interaction (RERI: 0.79; AP: 0.49). Mental health findings were less consistent: good mental health and low SEP was associated with increased HED (OR: 1.35), while moderate mental health and intermediate SEP was associated with decreased HED (OR: 0.66). Findings suggest a dose-response relationship between HRQoL and self-reported heavy drinking and an interaction between moderate HRQoL and low SEP. Associations with mental health were weaker and inconsistent.