Researchers found that children who were overweight at age eight or 13 had more than triple the risk of developing major depression later in life, while carrying excess weight over a lifetime (both as a child and as an adult) quadrupled the chance of developing depression compared to only being overweight as an adult.
More than one in three children in the U.S. are overweight and nearly one in five children aged between two and 19 years are obese, according to the Centers for Disease Control and Prevention.
Previous research has shown that people who are obese are more likely to become depressed, but few have looked at the influence of early-life obesity over the long term, or the age-related effect of obesity on depression risk.
For the study, researcher Dr. Deborah Gibson-Smith from VU University Medical Center in the Netherlands and colleagues observed the relationship between being overweight in childhood and lifetime depression in 889 participants from the population-based AGES (Age, Gene/Environment Susceptibility) Reykjavik study (begun in 1967). They also studied whether the detrimental effect of obesity on mental health is due to lifelong obesity or the result of being overweight in adulthood.
A random sample of surviving participants (average age 75) from the Reykjavik study were assessed to see whether they had current depressive symptoms or had ever had a major depressive disorder in the past. Data on height and weight during childhood and midlife were obtained from school records and the Reykjavik study, respectively.
A BMI of between 25 and 29.9 was considered overweight. The data were adjusted for sex and the age at which the BMI measurements were taken. A total of 39 participants had been diagnosed with major depression at some point in their lifetime.
The analysis revealed that carrying excess weight in childhood was a stronger predictor of subsequent depression than being overweight in midlife only. The researchers estimate that being overweight or obese at age eight or 13 years is associated with a more than four times increased risk of lifetime major depressive disorder compared with children who were normal weight as a child but went on to become overweight as adults (a statistically significant result).
This is an observational study so no conclusions can be drawn about cause and effect. But the findings confirm earlier research showing an increased risk of depression in young people who are obese.
“Our findings suggest that some of the underlying mechanisms linking overweight or obesity to depression stem from childhood,” the authors stated. “A shared genetic risk or low self-esteem, which is frequently associated with those who do not conform to the ideal body type, could be responsible.”
“Given the rise in adolescents’ obesity and greater influence of social media on body image, understanding the associations between childhood obesity and depression is critical.”