Approximately 17% of the workforce of the European Union is now engaged in shift work(1). Shift work has been reported to adversely affect the health of workers, leading to a higher risk of overweight/obesity and other chronic diseases(2). This study aimed to compare the lifestyle and dietary characteristics of normal weight and overweight/obese shift workers.
A cross-sectional study was conducted on 1,072 consenting shift workers using a 15-minute telephone questionnaire to establish demographic factors, shift work schedules, current food/drink consumption and snacking habits among shift workers living in Ireland. The questionnaire was developed from Irish qualitative research with shift workers(3, 4). Body Mass Index (BMI, kg/m2) was calculated using self-reported height (m) and weight (kg) measurements, and data were analysed according to WHO BMI categories: Normal weight, BMI 18·5–24·9 kg/m2 vs. overweight/obese BMI >25 kg/m2.
Within this group of shift workers, 43·7% were classed as overweight or obese. Univariate analysis indicated that being male, middle/older-aged, consuming <5 portions fruit/vegetables per day and having medium-high fried food consumption were associated with overweight/obesity. Smoking and exceeding units of alcohol per week were associated with normal BMI. Following multivariate analysis, being male [p < 0·001, OR = 2·31, 95% CI (1·73–3·09)] and middle/older aged were independently associated with overweight/obese BMI [p < 0·001, OR = 2·54 95% CI (1·85–3·49) and p < 0·001, OR = 2·89 95% CI (1·87–4·48) respectively]. Dietary behaviours independently associated with overweight/obese BMI included medium-high consumption of fried food [OR = 1·97, 95% CI (1·48–2·63)] and eating less than the recommended number of portions of fruit and vegetables per day [OR = 1·38, 95% CI (1·07–1·79)]. Exceeding recommended units of alcohol per week remained associated with a normal BMI [OR = 0·62, 95% CI (0·38–0·99)]. Smoking was not associated with BMI following multivariate analysis.
This study indicates that shift work is associated with lifestyle and dietary characteristics of shift workers, regardless of BMI. Male and middle/older age shift workers may benefit from targeted dietary and lifestyle advice to protect against overweight and obesity.
This work was supported by safefood, the Food Safety Promotion Board, under Grant No. 10–2013. Ethical approval was obtained from the Dublin Institute of Technology Research Ethics Committee and the study was conducted according to the guidelines laid down in the Declaration of Helsinki.