Washington: Scientists have claimed that black women who work at night face an increased risk of developing diabetes, than those who have never worked night shifts.
Data from a large ongoing study by Dr Varsha Vimalananda, into the health of African-American women show more years working the night shift result in a higher risk. Furthermore, the increased risk of diabetes seen in shift workers was more pronounced in younger women than older women.
Dr Vimalananda is from Center for Health Organization and Implementation Research (CHOIR), Edith Nourse Rogers Memorial Veterans Affairs Medical Center, Bedford, MA, USA.
In the study, 28,041 participants free of diabetes provided information in 2005 about having worked the night shift. The women were followed for incident diabetes during the next 8 years. Thirty-seven percent of the women reported having worked the night shift, with 5 percent having worked that shift for at least 10 years. During the 8 years of follow-up, there were 1,786 incident diabetes cases.
Relative to never having worked the night shift, the increased risk of developing diabetes was 17 percent for 1-2 years night shift work; 23 percent for 3-9 years, and 42 percent for 10 or more years. After adjustment for BMI and lifestyle factors such as diet and smoking status, the association between increasing years of night shift work and increasing diabetes risk remained statistically significant, with a 23 percent increase in those who had worked night shifts for 10 years or more versus those who never had worked the night shift.
When black women having ever worked the night shift (any duration) were compared to those who had never worked it, they were found to be at a 22 percent increased risk of developing diabetes. After adjustment for BMI and lifestyle factors, this increased risk became 12 percent.
The authors also found that the association was stronger in younger women than in older women. Working night shifts for 10 or more years relative to never working the night shift was associated with a 39 percent higher risk of diabetes among women aged less than 50 years compared with 17 percent higher risk in women aged 50 years or over.
The authors concluded that they found that African-American women undergoing long-duration night-shift work had a higher risk of incident diabetes. The fact that the association remained, though reduced, after adjustment for lifestyle factors and BMI suggests that additional pathways such as disruption of the circadian system may be playing a role.
The study is published in Diabetologia, the journal of the European Association for the Study of Diabetes.
