A new study suggests seniors with depression are more likely to develop a form of diabetes often associated with obesity — but researchers are puzzled by the fact that weight gain did not appear to explain the link between the two conditions.
Over a 10-year period, Mercedes Carnethon of Northwestern University in Chicago and her colleagues evaluated nearly 4,700 people who initially did not have diabetes and were at least 65 years old. Each year, the participants were asked to rate how often they experienced problems with mood, irritability, energy, concentration and sleep in the previous week. A score of eight or higher on this scale qualifies as high depressive symptoms.
At the beginning of the study, 20 per cent of participants had a score of eight or higher. During followup, at least 47 per cent of patients experienced an increase of at least five in their score, while 38 per cent had two consecutive scores of eight or higher.
After taking into account factors such as age, race, gender, education, marital status, smoking and obesity, the researchers found that patients who experienced an increase in their score of at least five points had a 63 per cent higher risk of developing type 2 diabetes, a condition in which the body no longer makes enough of the hormone insulin or doesn’t respond properly to it.
The researchers note that their findings differ from previous studies in that the association between depression and diabetes was still significant even after adjusting for risk factors such as obesity.
“High depressive symptoms may be related to the development of diabetes in older adults, and this association may not be attributable solely to the adoption of adverse health behaviours or weight gain,” they conclude, adding that the explanation for the association remains unclear.