Relationship of type of work with health-related quality of life.

PURPOSE: To examine the relation of work type with health-related quality of life (HRQoL) in healthy workers. METHODS: We cross-sectionally examined 4427 (3605 men and 822 women) healthy workers in Japan, aged 19-69 years. We assessed HRQoL based on scores for five scales of the SF-36. Multiple regression was applied to examine the relation of work type (nighttime, shift, day to night, and daytime) with the five HRQoL norm-based scores, lower scores of which indicate poorer health status, adjusted for confounding factors, including sleeping duration. RESULTS: Shiftwork was inversely related to role physical [regression estimate (ß) = -2.12, 95 % confidence intervals (CI) -2.94, -1.30, P < 0.001], general health (ß = -1.37, 95 % CI -2.01, -0.72, P < 0.001), role emotional (ß = -1.24, 95% CI -1.98, -0.50, P < 0.001), and mental health (ß = -1.31, 95% CI -2.01, -0.63, P < 0.001) independent of confounding factors, but not to vitality. Day-to-nighttime work was inversely related to all the five HRQoL subscales (Ps 0.012 to <0.001). CONCLUSION: Shiftwork was significantly inversely related to four out of the five HRQoL, except for vitality, and day-to-nighttime work was significantly inversely related to all five HRQoL, independent of demographic and lifestyle factors.

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 components(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 ≥140mg/dl, or on medication for diabetes mellitus; 4) overweight: a body mass index ≥25kg/m(2). 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.