Genetic variants linked to a high body-mass index are also associated with depression, particularly among women, the Guardian reports.
Researchers from Australia and the UK conducted a Mendelian randomization study using 48,791 individuals with depression and 291,995 controls from the UK Biobank. As they report today in the International Journal of Epidemiology, the researchers developed a genetic risk score for BMI based on 73 genetic variants and found that each standard deviation higher BMI was also associated with an increased risk of depression, 18 percent overall and 24 percent among women. This effect also held in cases and controls from the Psychiatric Genomics Consortium.
The researchers also conducted this analysis using variants linked to higher BMI, but a more favorable metabolic profile in a bid to disentangle the psychological and metabolic effects of obesity. These, too, were linked to an increased risk of depression, they report.
"It suggests the psychological component is just as strong as any physiological component, if [the latter] is there at all," co-author Timothy Frayling from the University of Exeter Medical School tells the Guardian.