The effect of commencing rotating shift work on diet and body composition changes in graduate paramedics: a longitudinal mixed methods study.

Objectives Diet quality often changes as shift workers adjust to atypical work schedules, however, limited research exists examining the early effects of starting rotating shift work on diet and body composition. This study explored dietary behavior changes occurring in graduate paramedics during the first year of exposure to rotating shift work, and investigated dietary intake, diet quality and anthropometric changes over two years. Methods Participants from a graduate paramedic cohort in Melbourne, Australia were approached after two years of shift work for study inclusion. Using a mixed method study approach, the qualitative component comprised individual in-depth interviews to explore perceived dietary behavior changes experienced over the first year of shift work. Interview transcripts were thematically analysed and guided by the COM-B model (capability, opportunity, motivation, and behavior) and theoretical domains framework (TDF). Diet quality and dietary intake were quantitatively assessed by the Australian Eating SurveyTM at baseline, one year, and two years, along with body weight, waist circumferenc,e and body mass index (BMI) to monitor changes. Results Eighteen participants were included in the study. From the interviews, participants reported: 1. food choices are driven by wanting to fit in with co-worker food habits, 2. food choices and mealtimes are unpredictable and 3. paramedics try to make healthy food choices but give in to less healthy options. While daily energy intake and diet quality scores did not differ in the first two years of shift work, daily energy from takeaway foods significantly increased (mean difference (MD): 2.96%EI; 95% CI: 0.44 - 5.48; p = 0.017) and increases in weight (MD: 2.96kg; 95% CI: 0.89-5.04; p = 0.003), BMI (MD: 1.07kg/m2 ; 95% CI: 0.26-1.87; p = 0.006) and waist circumference (MD: 5.07cm; 95% CI: 1.25-8.89; p = 0.006) were also evident at two years. Conclusions This study contributes new information on dietary changes and the current early trajectory of unintentional weight gain and takeaway reliance occurring within a graduate paramedic cohort over two years of shift work. To reduce the unintended metabolic consequences commonly observed with rotating shift schedules, workplaces could improve access to healthier food options and enable behavioral support/education to address nutrition-related health risks.