Compared to girls at a healthy weight, girls with obesity were 44 per cent more likely to have depression or to be diagnosed with it in the future, the analysis of 22 studies with a total of almost 144,000 participants found.
The smaller studies included in the analysis were not controlled experiments designed to prove whether or how obesity might cause depression, or the role that gender might play. But it is possible boys and girls might have different perceptions about body image that at least partially explain the results, said lead author Dr Shailen Sutaria of Imperial College London in the UK.
“While a number of factors may be involved, clearly there are additional social pressures on girls to be a certain body shape, perpetuated and amplified though social media,” Sutaria said.
Girls who experience body dissatisfaction may develop symptoms of depression as a result, Sutaria added. But overweight or obese boys might think differently about their size.
“Boys may find it desirable to be larger as this reflects strength and dominance, traits that are likely to be desirable during childhood,” Sutaria said.
Globally, more than 40 million children are overweight or obese by the time they’re 5 years old, according to the World Health Organization.
Depression is also a leading cause of reduced quality of life for children, impacting school performance, friendships and the risk of substance use and other risky behaviours, researchers note in the Archives of Disease in Childhood.
While previous research has linked childhood obesity to an increased risk of depression, results have been mixed and the estimated excess risk has ranged from as low as 4 per cent to as high as 64 per cent, researchers note.
In the current analysis, children were 14 years old on average and almost 16 per cent were obese. Slightly more than one in 10 obese children were depressed.
“We know that children with obesity are at risk of developing depression and we know that children with depression are at risk of developing obesity,” said Dr Stephen Pont, a researcher at the University of Texas Dell Medical School in Austin who wasn’t involved in the study.
Still, parents should keep the risk of depression in mind when they try to encourage overweight or obese children to achieve a healthy weight, said Rebecca Puhl of the Rudd Center for Food Policy & Obesity at the University of Connecticut in Hartford.
That means avoiding talk about the scale, said Puhl, who wasn’t involved in the study.
“When parents talk to their teen about losing weight, the teen is more likely to turn to unhealthy dieting and maladaptive weight control behaviours – like binge eating,” Puhl added. “But when parent conversations instead focus on healthy behaviours like eating nutritious foods, rather than body weight, the teen is less likely to engage in those unhealthy behaviours.”
At home, parents should also make sure kids aren’t teased about their weight and that there’s a supportive environment that encourages healthy behaviour, said Eleanor Mackey of Children’s National Health System in Washington, D.C.
“Parents should also encourage friendships that support the adolescent without bullying,” Mackey, who wasn’t involved in the study, said by email. “Finally, if a parent notices changes in mood, attitude, or increase in sleeping, difficulty sleeping, poor concentration, irritability, or sad mood, please seek help.”