Work, Stress, and Health 2009: Global Concerns and Approaches. The 8th International Conference on Occupational Stress and Health, November 5-8, 2009, San Juan, Puerto Rico. Washington, DC: American Psychological Association, 2009 Nov; :1
Background: According to the Bureau of Labor Statistics, 14.8% of full-time wage and salary workers work a shift other than a regular daytime schedule. Shift work may be associated with poor nutritional habits that can increase the risk of various diseases. Studies have shown conflicting results concerning the type and amount of calories consumed by workers on different shifts. The objective of this study was to investigate the nutritional dietary intake of police officers across three shifts. Methods: This cross-sectional study was initiated among 115 randomly selected urban police officers, 108 of whom had complete data and had worked for at least 2 years prior to completing the dietary questionnaire. Shift work data were obtained from daily payroll records during 1994-2000 and were categorized as day, afternoon or midnight, based on the highest percent of hours worked on each of these shifts during the 2 years prior to baseline clinic visit. Participants were considered to work a day shift if the start time ranged between 4 am and 11 am; afternoon shift if the start time ranged between 12 pm and 7 pm; and midnight shift if the start time ranged between 8 pm and 3 am. Total hours worked as well as hours worked at the day, afternoon and midnight shift were computed for each participant. These shift work exposure variables were computed for regular scheduled work and over time work separately. This study used data collected in 1999 and 2000 from the Buffalo, New York Police Department. Officers completed self-administered dietary questionnaires. Researchers at the Fred Hutchinson Cancer Research Center for Nutritional Analysis converted the diet information into quantity of nutritional substances. These researchers used Nutrition Data Systems for Research software (NDSR) developed by the Nutrition Coordinating Center at the University of Minnesota for data entry and nutrient analysis. The associations between shift work and nutrient intake were analyzed using analysis of variance (ANOVA) and covariance (ANCOVA), where mean values of each nutrient of interest were compared across the shift types. Results: Participants in this study, 37% of whom were women, ranged in age from 26 to 61 years old (mean +/- SD: 39.3 +/- 7.5 years). Fifty-four officers (50%) were categorized as day shift workers, forty officers (37%) as afternoon shift workers and thirteen (13%) as midnight shift workers. The mean ages of the 108 officers who worked the day, afternoon, and midnight shifts were 41 +/- 8, 34 +/- 6, and 38 +/- 5 years respectively with day shift workers being significantly older (p=0.038). Current smoking was more prevalent in midnight shift workers (30.8%) than in day and afternoon workers (18.5% and 15.0%, respectively), although the difference was not statistically significant. Mean total calories consumed by officers working the midnight shift were fewer, but not significantly so (1703 +/- 245 kcal), than the quantity consumed by officers who worked day (1968 +/- 131 kcal) or afternoon (1963 +/- 149 kcal) shifts (age- and gender-adjusted p=0.608). Similarly, mean intake of carbohydrate, protein, and fat was somewhat lower among officers working the midnight shift compared to those working the day or afternoon shifts, although those associations were not statistically significant. Midnight shift officers reported lower mean levels of dietary Vitamin E intake (7.8 +/- 3.6 IU) than officers who worked day (17.0 +/- 1.9 IU) or afternoon (13.6 +/- 2.2 IU) shifts (age- and gender-adjusted p=0.096). This pattern was repeated for age- and gender-adjusted mean levels of vitamins A, C, and D. Among day, afternoon, and midnight shift officers, the adjusted mean dietary levels for vitamin A were 828.5 +/- 83.4 mcg RAE, 792.8 +/- 95.0 mcg RAE, and 563.5 +/- 156.4 mcg RAE respectively, p=0.333; for vitamin C, 123.0 +/- 12.8 mcg, 101.1 +/- 14.6 mcg, and 76.3 +/- 24.1 mcg respectively, p=0.233; and for vitamin D, 5.3 +/- 0.5 mcg, 5.7 +/- 0.6 mcg, and 3.9 +/- 1.0 mcg respectively, p=0.303. Conclusion: We found officers who worked the midnight shift tended to consume fewer total calories, and less carbohydrate, protein, fat, and nutrients important (e.g. vitamins) to health than officers on the day or afternoon shift, although these differences were not statistically significant. Prospective studies, with larger sample sizes, are necessary to further investigate this relationship between shift work and nutrient consumption.
Cathy A. Tinney-Zara, MPH, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26501