Relationship between shift work and clustering of the metabolic syndrome diagnostic components

Aim: to examine the relationship between the type of work and the number of metabolic syndrome diagnostic componentss (mets-dc),as well as the risk of mets,with adjustment for lifestyle habits in japanese workers. methods: we examined the baseline data from 4,427 participants (81.4% male) aged 19 to 69 years old. the physical activity of each participant was classified according to the international physical activity questionnaire (ipaq). we defined the four mets-dc in this study as follows: 1) high blood pressure (bp): systolic bp ≥ 130 mmhg,or diastolic bp ≥ 85 mmhg,or the use of antihypertensive drugs; 2) dyslipidemia: high-density lipoprotein-cholesterol concentration <40 mg/dl or triglyceride concentration ≥ 150 mg/dl,or on medication for dyslipidemia; 3) dysglycemia: fasting blood sugar level ≥ 110 mg/dl,or if less than eight hours after meals ≥ 140 mg/dl,or on medication for diabetes mellitus; 4) overweight: a body mass index ≥ 25 kg/m2. we defined mets as overweight plus two or more of the mets-dc. results: there were 3,094 subjects in the daytime work group,73 in the fixed nighttime work group,1,017 in the shift work group and 243 in the day-to-night work group. the poisson regression analysis revealed that fixed nighttime (regression coefficient [b] = -0.233,p=0.028) and shift work (b=0.098,p=0.034) independently contributed to the number of mets-dc,compared to daytime work. the multivariate logistic analysis not including sleep hours in the model showed that shift work was positively related to mets (odd ratio = 1.47,p<0.01). conclusion: shift work were significantly associated with the number of mets-dc,and was related to risk of mets compared to daytime work.