Background: Shift work has been associated with increased body mass index (BMI), metabolic disruption and increased chronic disease risk. Typically, these reports compare individuals who work the day shift to those who work the night shift. Because shift assignment is not random, differences may reflect other, unmeasured characteristics that account for outcome differences.
Objective: To compare dietary intake on days on which the participant worked the night shift to days on which she worked the day shift in a population of female nurses who work rotating shifts at a hospital.
Methods: This cross-sectional study recruited 132 female registered nurses who work rotating shifts in surgical or internal medicine departments. Dietary intake was ascertained using food diaries and analyzed on Tzameret Nutrition Analysis Software (Israel Ministry of Health). Demographic and anthropometric variables were also recorded.
Results: Compared to dietary intake on a day the nurse worked the day shift, intake of the following nutrients increased significantly on the day she worked the night shift: energy; protein; carbohydrates; total fat; saturated fat; and calcium.
Discussion: A significant increase in calorie, macronutrient and calcium intake on days the night shift was worked compared to days the day shift was worked among female nurses who work rotating shifts was demonstrated. These findings could be extended to other professionals who work rotating shifts, including physicians and allied healthcare personnel. It appears that the difference detected may be influenced by the food supplied by the hospital as well as by increased food intake in general.
Keywords: Shift work; body weight; dietary intake; nutrition; occupational medicine.