Association of body mass index with lifestyle and rotating shift work in Japanese female nurses

Abstract

Objective: Higher body mass index (BMI) values have been reported in rotating shift workers compared with regular daytime workers. This study examines the relationship between work schedule and BMI, and considers whether lifestyle habits could explain the relationship. Methods: Japanese female nurses (1179 day workers and 1579 rotating shift workers, aged 20-59) were studied using self-administered questionnaires. The questionnaires assessed height, weight, and dietary intake, physical activity, and sleep (lifestyle) habits. Results: The BMI of shift workers was significantly higher than that of day workers. Shift workers consumed significantly higher amounts of sugar-sweetened beverages and slept for significantly shorter durations on nights between days on the day shift compared with day workers-factors which were also independently associated with higher BMI. In addition, multivariable linear regression coefficients for BMI showed a significant correlation with rotating shift work (b 5 0.051), after controlling for lifestyle habits. Conclusions: Higher consumption of sugar-sweetened beverages and shorter sleep duration were associated with rotating shift work and higher BMI. This should be taken into consideration in preventing obesity in real-life shift work situations. Other shift work-related factors, such as abnormal timing of meals and/or sleep, should also be identified.

Shift workers have a similar diet quality but higher energy intake than day workers

“…In contrast to our finding of a higher energy intake among shift compared to day workers, the majority of previous studies observed no significant differences (15,17,19,24,39,40). However, three of these studies observed a statistically non-significantly higher energy intake among shift compared to day workers (24,39,40).…”

“…During irregular shifts, shift workers tend to eat a larger number Shift work and diet of small meals and eat more at irregular times (13,14). As to their usual diet, shift workers seem to consume more high-energy snacks and sugars than day workers (14)(15)(16)(17). Shift workers were also found to have a lower intake of fruits and vegetables (17,18), fiber (19) and some vitamins and minerals (eg, vitamin B, C, magnesium) (19) than day workers.…”

“…As to their usual diet, shift workers seem to consume more high-energy snacks and sugars than day workers (14)(15)(16)(17). Shift workers were also found to have a lower intake of fruits and vegetables (17,18), fiber (19) and some vitamins and minerals (eg, vitamin B, C, magnesium) (19) than day workers. In contrast, one study has shown a higher consumption of fruits for shift workers in comparison with day workers (20), and other studies showed no differences for fruits and vegetables (21), vitamin C (18) and fiber (18,22).…”

“…Most of these studies also lacked adjustment for major confounders, such as age (13)(14)(15)(16)(17)(19)(20)(21)(22)(23)(24). Another important drawback is that the available studies focused on single nutrients or foods (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). For a comprehensive evaluation of differences in dietary intake, it is important to study dietary patterns because different nutrients and foods have additive and synergistic interactions (25).…”

Overtime, Shift Work, Poor Sleep and the Effects on Obesity: A Public Health Problem

“…The costs associated with poor sleep, unhealthy lifestyle behaviours and obesity extend beyond the worksite organization and negatively affect the individual and society. Numerous studies have reported on negative changes in sleep quality in employees working rotating or night shifts [21][22][23]. Further, employees working night shift may exhibit differences in lifestyle habits, such as increased sugar-sweetened beverage consumption [22], higher caloric intake and smoking status [23] which in turn is associated with increased BMI, [22,24,25] and elevated chronic disease risk [23].…”