Children whose parents are divorced tend to be heavier than kids whose parents stay married, a new study suggests.
Researchers in Norway found that kids from divorced homes in that country were 54 percent more likely to be overweight or obese, and 89 percent were more likely to have abdominal obesity (too much weight around the waistline), compared with children from families with married parents.
The results also showed that boys from marriages that split up may be particularly vulnerable to gaining excess weight, especially around the waist, the researchers said. Having excess belly fat may increase a person's risk for diabetes and heart disease, and could possibly shorten life span.
"We now have knowledge about how childhood overweight and obesity is distributed" among the Norwegian population, said study author Anna Biehl, a doctoral candidate at the Norwegian Institute of Public Health in Oslo.
But she cautioned that "the results do not say that divorce causes weight gain in children." Although the research sheds light on whether there were any associations between family structure and children being overweight and obese in Norway, it was not designed to establish a cause-and-effect relationship between these factors. [10 Ways to Promote Kids' Healthy Eating Habits]
The findings are published today (June 4) in the online journal BMJ Open.
Boys more vulnerable
The study analyzed data from about 3,100 third graders in Norway. Researchers measured each child's weight, height and waist circumference, and calculated body mass index and waist-to-height ratio.
They also gathered details on the marital status of kids' parents, dividing them into three groups: married, divorced and never married, which included couples who were living together as well as parents who were single or had separated.
Among the 8- and 9-year-olds in the study, more girls were overweight than boys, regardless of their parents' marital status, the researchers found. But there was evidence that boys were especially prone to weight problems after a marriage broke up — even more so than girls.
Boys with divorced parents were 63 percent more likely to be overweight or obese, and 104 percent more likely to have abdominal obesity, than boys whose parents stayed married. These results held true even after the researchers took into account factors such as a mother's education level, current area of residence and family country background, all of which could influence kids' tendency to put on weight.
Boys whose parents never tied the knot, were separated or came from single-parent homes had similar rates of being overweight and obese as boys with married parents, according to the study.
Unclear reasons
Family structure also made a difference in the rates of Norwegian girls with weight problems but not to as great a degree as the associations in boys.
Girls with divorced parents were 34 percent more likely to be too heavy than girls whose parents were still married, the analysis found.
The gender differences in the study were "somewhat surprising," Biehl told LiveScience. However, she added that the team did not investigate the possible reasons for the differences.
So, why might divorce widen some kids' waistlines? The paper speculates on some possibilities, including less money for parents to spend on food and less time to prepare healthy meals, as well as more emotional stress in the home, which could affect kids' eating and exercise habits.
One limitation of the study is that slightly more than 7 percent of the Norwegian couples involved in the research were divorced, so this sample size was small and represented only 230 children.
Researchers also lacked information about how long couples had been divorced, and they had no data on the children's eating and exercise habits.
Knowledge about the link between family structure and the prevalence of obesity in children could be important for preventive work, Biehl said. The results could add "valuable background information about potentially vulnerable groups at risk for developing adiposity," the researchers wrote.
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