Objective: To investigate the relation between exposure to night work and prevalence of overweight and weight gain.
Design: Longitudinal observational study.
Subjects: 469 nurses (age: 21-58 y).
Measurements: Body Mass Index, exposure to night work, age, parity, smoking and sports activities in 1980, 1985 and 1990.
Results: Prevalence of overweight was associated with exposure to night work in 1980 and weight gains (especially those exceeding 7 kg) were more frequent among nurses on night work than on daytime work between 1985 and 1990.
Conclusion: Exposure to night work can lead to weight gain and overweight.