Odds are highest for younger women and those doing shift work for many years
WebMD News from HealthDay
By Robert Preidt
MONDAY, Jan. 12, 2015 (HealthDay News) Night shift work significantly increases the risk of diabetes in black women, according to a new study.
"In view of the high prevalence of shift work among workers in the U.S.A. -- 35 percent among non-Hispanic blacks and 28 percent in non-Hispanic whites -- an increased diabetes risk among this group has important public health implications," wrote the study authors from Slone Epidemiology Center at Boston University.
It's important to note, however, that the study wasn't designed to prove that working the night shift can cause diabetes, only that there is an association between the two.
The new research included more than 28,000 black women in the United States who were diabetes-free in 2005. Of those women, 37 percent said they had worked night shifts. Five percent said they had worked night shifts for at least 10 years, the researchers noted.
Over eight years of follow-up, nearly 1,800 cases of diabetes were diagnosed among the women.
Compared to never working night shifts, the risk of diabetes was 17 percent higher for one to two years of night shifts. After three to nine years of night shift work, the risk of diabetes jumped to 23 percent. The risk was 42 percent higher for 10 or more years of night work, according to the study.
After adjusting for body mass index (BMI -- an estimate of body fat based on height and weight) and lifestyle factors such as diet and smoking, the researchers found that black women who worked night shifts for 10 or more years still had a 23 percent increased risk of developing diabetes. And those who had ever worked the night shift had a 12 percent increased risk.
The link between night shift and diabetes was stronger in younger women than in older women. Compared to never working the night shift, working night shifts for 10 or more years increased the risk of diabetes by 39 percent among women younger than 50 and by 17 percent among those 50 and older.