The aim was to investigate the mediating effect of BMI on the relationships between occupational stress and metabolic syndrome in workers. In a cross-sectional study of 841 petroleum refinery workers in Hainan, South China, a self-designed questionnaire was used to collect baseline/occupational data and the Effort–Reward Imbalance (ERI) questionnaire was used to assess occupational stress. Trained physicians measured height, weight, abdominal circumference, and blood pressure; lipid profiles and fasting glucose levels were analyzed biochemically. Metabolic syndrome (MetS) was diagnosed using the NCEP-ATP-III criteria. In this study, correlations between BMI and MetS were analyzed between groups with and without occupational stress, and a mediation analysis was performed to examine the role of BMI in the relationship between occupational stress and MetS. The median age of the 841 participants was 31 (25 ~ 37) years, and the median length of service was 8 (2 ~ 15) years. There were 733 males (87.16%) and 108 females (12.84%). The median age and work tenure of the male workers were 32 (25 ~ 37) years and 9 (2 ~ 16) years, respectively, and those of the female workers were 26 (24 ~ 31) years and 2 (2 ~ 8.75) years, respectively. Among the workers, 268 and 573 did and did not experience occupational stress. The prevalence of MetS was greater (OR = 1.666, 95% CI: 1.039 ~ 2.671) and the BMI was greater (β = 0.684, 95% CI: 0.100 ~ 1.269) in those with occupational stress. Moreover, the BMI was significantly greater in the MetS group than in the non-MetS group (β = 1.299, 95% CI: 1.217 ~ 1.386). The mediation analysis confirmed no significant direct effect of occupational stress on MetS (direct effect, 95% CI: -0.074 ~ 0.009); however, the effect was significant when mediated by BMI (indirect effect, 95% CI: -0.029~-0.003). Occupational stress is associated with an increased prevalence of MetS and elevated BMI in workers. A positive correlation between BMI and the prevalence of MetS was observed. Furthermore, BMI may mediate the effect of occupational stress on the increased prevalence of MetS. However, this study is a cross-sectional study; future longitudinal studies could further test the causal associations between these study variables.
Zhou et al. (Sat,) studied this question.