Author's Reply.

Dear Editor,

Consideration of non-occupational factors such as smoking, obesity, drinking, and low physical activity, which are risk factors for metabolic syndrome, is not mentioned in the discussion section of the article.[1] These factors have already been discussed in other studies.

I agree that interpretation of results is very important. We found that shift work and low physical activity are non-significant risks for metabolic syndrome (Table 1 of the article[1]). Although the reported ORs are <1 (reflecting protection), because the effects are not statistically significant, the observed effects are more likely attributed to the sampling variation rather than a true effect. On the other hand, although shift work and low physical activity were not found significantly associated with metabolic syndrome, some researchers reported a significant association between these variables and metabolic syndrome. These results are expected to be attributed to the characteristics of the environment where the subjects work in the labor intensive manufacturing environment.

Finally, the work experience of participants was not available. This is one of limitations of this study.