Study: Depression may be both a risk factor and consequence of diabetes

NEW YORK — A new study published in the Nov. 22 issue of Archives of Internal Medicine suggested there is a two-way relationship between depression and diabetes.



An Pan of the Harvard School of Public Health and colleagues assessed the relationship between the two diseases among 65,381 women who were ages 50 years to 75 years in 1996. After completing an initial questionnaire about their medical history and health practices, participants completed follow-up questionnaires every two years through 2006. The study subjects were classified as having depression if they reported symptoms of depression, using antidepressant medication or being given a diagnosis of depression by a physician. Women who reported a new diagnosis of diabetes completed a supplementary questionnaire about symptoms, diagnostic tests and treatments, the authors said.



During the 10-year follow-up, 2,844 women were diagnosed with Type 2 diabetes, and 7,415 developed depression. Women with depression were about 17% more likely to develop diabetes after controlling for other risk factors, such as physical activity and body mass index. Those who were taking antidepressants had a 25% higher risk of developing diabetes than those who did not have depression.



After controlling for other risk factors for mood disorders, women with diabetes were 29% more likely to develop depression. Women who took insulin for diabetes had a further increased risk — 53% higher than women without diabetes.



"The findings from this well-characterized cohort of more than 55,000 U.S. women with 10 years' follow-up add to the growing evidence that depression and diabetes are closely related to each other, and this reciprocal association also depends on the severity or treatment of each condition," the authors wrote. "All the associations were independent of sociodemographic, diet and lifestyle factors."



The study was supported by a National Institutes of Health grant.