Associations between precarious employment and smoking and regular exercise: Results from a Korean longitudinal panel study from 2005 to 2020.

We examined whether precarious employment (PE) is related to cigarette smoking and physical inactivity and whether a longer duration of PE intensifies the detrimental impact. Using Korean longitudinal panel data, 89,289 observations of 15,712 employees were analyzed. Mixed models were applied to estimate the odds ratio (OR) and 95% confidence intervals (CIs). We adjusted for time-varying characteristics of the participants (age, education, marital status, income, occupation, and working hours). ORs of associations between PE and current smoking were 1.09 (95% CI: 0.95-1.25) in men and 1.77 (1.03-3.05) in women. Also, ORs of associations between PE and regular exercise were 0.52 (0.46-0.58) in men and 0.95 (0.85-1.07) in women. Next, the longer the duration of PE was related to the higher the risk of current smoking and physical inactivity. For instance, over 6 years of PE was related to the highest risk of current smoking in men (1.80 [1.38-2.34]) and women (3.94 [1.25-12.44]). Also, over 6 years of PE was related to the lowest likelihood of regular exercise in men (0.47 [0.37-0.59]), but not in women (0.83 [0.65-1.06]). A longer duration of PE is also related to a change in health behaviors among men. Over 6 years of PE was associated with the highest risk of smoking initiation (2.02 [1.28-3.19]) and the lowest likelihood of exercise initiation (0.42 [0.32-0.55]) in men. However, a longer duration of PE was not associated with a change in health behaviors in women. Our findings highlight that PE have a detrimental impact on health behaviors.