The relationship between shift work and the onset of hypertension in male Japanese workers.

We assessed the effect of shift work on the onset of hypertension. The design of this study was that of a cohort study from 1991-2001. In sum, 5338 workers comprised this cohort. The event was the onset of hypertension (systolic blood pressure >or=140 mm Hg and/or diastolic blood pressure >or=90 mm Hg and/or medication). Pooled logistic regression analysis was performed, including job schedule type, age, body mass index, lifestyle, and the results of blood chemistries as covariates. The odds ratio of the onset of hypertension in shift workers for daytime workers was 1.10 and significant. Our study revealed that shift work independently affected the onset of hypertension, and suggested that shift work is a risk factor for the onset of hypertension.