Objective This study aimed to determine an association between shift work and the metabolic syndrome (MetS) in the electronics industry.

Methods In total, 12 583 employees who participated in health examination and questionnaire were evaluated. MetS was measured by the National Education Program Adult Treatment Panel III (NCEP) criteria using examination results. We performed multiple logistic regression analyses to test the relationship between shift work and MetS.

Results The prevalence rate of MetS among total group was 8.8%. After controlling for the potential confounders, MetS of male daytime workers was more prevalent compared to shift workers. However, prevalence of the MetS showed significant increasing risk according to the number of years of shift work (a period of 5~9 years : OR 3.48, 95% CI 1.20–10.08; 10~14 years : OR 4.14, 95% CI 1.34–12.74; 15 years : OR 5.72, 95% CI 1.83–17.83 vs. 1~4 years). Although no significant differences in prevalence of the MetS between daytime and shift work were observed, the risk for the development of MetS increased with accumulated years of shift work among women (a period of 5~9 years : OR 3.12, 95% CI 1.72–5.67; 10~14 years : OR 5.57, 95% CI 2.91–10.66; 15 years : OR 5.17, 95% CI 2.48–10.81 vs. 1~4 years).

Conclusion This study suggests that the duration of shift work increases the risk for developing the MetS.