Differences in nutritional profile by chronotype among 12-h day shift and night shift nurses

Acute care nurses may suffer substantial fatigue if working night shift or if assigned a shift contrasting their preferred sleep-wake patterns, called chronotype. Nurses are at higher risk for diet-related, metabolic diseases compared to other healthcare professionals. Yet, the impact of preferred chronotype and mismatch to assigned shift on nutritional intake and risk for metabolic disease among acute care nurses is unclear. This observational study analyzed dietary data from 52 acute care nurses. Participants completed the revised morningness-eveningness questionnaire which gives a total score between 4 and 26. Lower scores (<12) were flagged as evening type (E-type), higher scores (>17) defined as morning type (M-type), and scores between 12 and 17 were categorized as neither types (N-type). N-type participants were considered chronotype matched when assigned to either shift, whereas E-types were only considered matched if assigned to night shift, and M-types matched only if assigned to day shift. Participants also recorded all dietary intake for 7 d (reflecting a typical workweek) in the MyFitnessPal phone application. Findings indicated that eveningness nurses had markers of MetS, including a significantly larger body mass index and waist circumference than N-types (p < 0.05). E-types also consumed, on average, more calories than other chronotypes (m = 1833.7 kcal), although this was not a statistically significant finding. Mismatched day (n = 7, 13.4%) and night (n = 5, 9.6%) nurses in our sample consumed, on average, more calories (m = 1935.1 kcal, m = 1981.2 kcal, respectively) than matched day (n = 24, 46.2%, m = 1642.6 kcal) or night (n = 16, 30.8%, m = 1599.1 kcal) nurses, although this finding was not statistically significant. Mismatched day nurses consumed significantly less fiber than day matched nurses (median = 10.9 g versus median = 18.5 g, p = 0.04), while night mismatched consumed significantly more fiber compared to night matched (median = 21 g versus median = 12.2 g, p = 0.05) nurses. Participant diets overall did not follow recommendations by the United States Department of Agriculture (USDA), who consumed a higher percentage of calories from saturated fats and a smaller percentage of calories from fiber, habits which increase risk for metabolic syndrome. Further research surrounding nutritional pathways utilizing larger samples is needed to uncover relationships with metabolic syndrome especially for eveningness-type nurses or if working a shift mismatched with preferred chronotype.