According to Lu's team, erratic working schedules make it more difficult for the body to establish a sleep-wake cycle, and poor sleep may worsen insulin resistance, a precursor to diabetes.
Previous studies have also linked shift work to weight gain and obesity, a big risk factor for type 2 diabetes. And the researchers note that shift work can also affect cholesterol levels and blood pressure.
Another expert said other factors may be at play as well.
"Growth hormone, known to elevate blood glucose when present in excess, peaks at 1 a.m.," noted Dr. Gerald Bernstein, director of the Diabetes Management Program at Friedman Diabetes Institute at the Beth Israel Medical Center in New York City. "Shift work also often makes it more difficult to schedule regular meals and exercise."
Still, Bernstein said that "even with a strong risk for diabetes I would not discourage someone from taking a job that is based on shifts."
Instead, he said "it would be better to screen shift workers regularly for pre-diabetes and intervene to slow the progression to full-blown diabetes."
Manevitz agreed. "Those who must do shift work would be wise to consult their doctor, who can monitor cholesterol levels, blood pressure and insulin levels to detect if blood sugar levels are creeping up dangerously," he said. "Doctors may also be able to prescribe sleep aids to help shift workers get the proper amount of sleep, even if that sleep comes during odd hours."
The study was published recently in Occupational & Environmental Medicine.
The American Psychological Association provides more information on the health effects of shift work.
SOURCE: Alan Manevitz, M.D., clinical p
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