Effekten av skiftarbeid på kroppsmasseindeks

Forskere fra Universitetet i Bergen har i denne longitudinelle studien undersøkt hvordan kroppsmasseindeksen til sykepleiere i ulike skiftordninger utvikler seg over en 4-års periode. Studien viser at sykepleiere som arbeidet utelukkende natt hadde en signifikant økning i kroppsmasseindeks sammenlignet med sykepleiere som arbeidet utelukkende dag. Dette resultatet ble stående selv etter at man justerte for en rekke potensielle confoundere.

Shift work schedule and night work load: Effects on body mass index - a four-year longitudinal study

Studien er publisert i Scandinavian Journal of Work, Environment & Health

Hogne Vikanes Buchvold, Ståle Pallesen, Siri Waage og Bjørn Bjorvatn

Objectives: The aim of this study was to investigate changes in body mass index (BMI) between different work schedules and different average number of yearly night shifts over a four-year follow-up period.

Methods: A prospective study of Norwegian nurses (N=2965) with different work schedules was conducted: day only, two-shift rotation (day and evening shifts), three-shift rotation (day, evening and night shifts), night only, those who changed towards night shifts, and those who changed away from schedules containing night shifts. Paired student's t-tests were used to evaluate within subgroup changes in BMI. Multiple linear regression analysis was used to evaluate between groups effects on BMI when adjusting for BMI at baseline, sex, age, marital status, children living at home, and years since graduation. The same regression model was used to evaluate the effect of average number of yearly night shifts on BMI change.

Results: We found that night workers [mean difference (MD) 1.30 (95% CI 0.70-1.90)], two shift workers [MD 0.48 (95% CI 0.20-0.75)], three shift workers [MD 0.46 (95% CI 0.30-0.62)], and those who changed work schedule away from [MD 0.57 (95% CI 0.17-0.84)] or towards night work [MD 0.63 (95% CI 0.20-1.05)] all had significant BMI gain (P<0.01) during the follow-up period. However, day workers had a non-significant BMI gain. Using adjusted multiple linear regressions, we found that night workers had significantly larger BMI gain compared to day workers [B=0.89 (95% CI 0.06-1.72), P<0.05]. We did not find any significant association between average number of yearly night shifts and BMI change using our multiple linear regression model.

Conclusions: After adjusting for possible confounders, we found that BMI increased significantly more among night workers compared to day workers.