Nov. 13 (UPI) -- A recent study presents strong evidence that higher body mass index can cause depression.
Researchers from the University of South Australia published a study detailing these findings in the International Journal of Epidemiology.
They examined 73 genetic variants connected to high body mass index that cause weight-related conditions, like diabetes or heart disease. At the same time they looked at 14 variants linked to obesity but that weren't associated with those same health problems.
"The strength of our study design is its ability to focus on the effects of high BMI, rather than any dietary or societal influences which would typically be associated with obesity," Elina Hypponen, co-author and doctor at the University of South Australia, told the Sydney Morning Herald.
The researchers took data from 500,000 participants, aged between 37 and 73 years from the UK Biobank, and contrasted the frequency of the obesity genetic variant present and the percentage of hospital admission and self-reported depression numbers.
The team compared genetic data from more than 48,000 people who self-reported having depression with a control group of more than 290,000 people.
"These genes were just as strongly associated with depression as those genes associated with higher BMI and diabetes," Hypponen told the Morning Herald.
The team concluded a strong link exists between people with high BMI and depression. The study, specifically, found that for every 4.7-point increase in BMI, the odds of becoming depressed increased by 23 percent for women and by18 percent, overall.
"Obesity and depression are both global health problems that have a major impact on lives and are costly to health services," Jess Tyrrell, doctor at the University of Exeter Medical School, said in a press release. "We've long known there's a link between the two, yet it's unclear whether obesity causes depression or vice-versa, and also whether it's being overweight in itself or the associated health problems that can cause depression. Our robust genetic analysis concludes that the psychological impact of being obese is likely to cause depression. This is important to help target efforts to reduce depression, which makes it much harder for people to adopt healthy lifestyle habits."