(HealthDay News) — Both rotating night shift work and unhealthy lifestyle are associated with an increased risk for type 2 diabetes among female nurses, with a significant additive interaction, according to a study published online in the BMJ.
Zhilei Shan, PhD, from Tongji Medical College in Wuhan, China, and colleagues conducted a prospective cohort study to examine the joint association of duration of rotating night shift work and lifestyle factors with type 2 diabetes risk. Participants included 143,410 women without type 2 diabetes, cardiovascular disease, or cancer at baseline from the Nurses’ Health Study and Nurses’ Health Study II.
The researchers identified 10,915 cases of incident type 2 diabetes during 22 to 24 years of follow-up. The multivariable-adjusted hazard ratios for type 2 diabetes were 1.31 and 2.3 per 5-year increment of duration of rotating night shift work and per unhealthy lifestyle factor, respectively. The hazard ratio was 2.83 for the joint association of per-five-year-increment rotating night shift work and per unhealthy lifestyle factor with type 2 diabetes, with a significant additive interaction (P for interaction < 0.001). The proportions of the joint association were 17.1, 71.2, and 11.3% for rotating night shift work alone, unhealthy lifestyle alone, and their additive interaction, respectively.
“These findings suggest that most cases of type 2 diabetes could be prevented by adherence to a healthy lifestyle, and the benefits would be larger in rotating night shift workers,” the authors write.