Shift work, job strain, and metabolic syndrome: Cross-sectional analysis of ELSA-Brasil.

BACKGROUND: Shift work and psychosocial stressors may contribute to higher metabolic syndrome (MetS) incidence. Few studies investigated whether the presence of both factors simultaneously has a synergic effect on risk of MetS.

METHODS: This cross-sectional analysis used baseline data (2008-2010) for 10 960 current workers from ELSA-Brasil. Multiple logistic regression was used to estimate independent associations between shift work and job strain and MetS. An interaction between these factors was tested by including a multiplicative term in the final model.

RESULTS: Exposure to three-shifts a week (that is, three 12 h shifts of work followed by 36 h of rest) and high job-strain were independently associated with greater risk of MetS. We found no indication (P > 0.05) of interaction between working in shifts and job strain on MetS.

CONCLUSIONS: Efforts to reduce job strain and shift work should be considered as part of a primary prevention strategy to reduce the risk of MetS.