Overweight teens more likely to die early, says study
young, according to a new study, which stresses the importance of
healthy eating habits in US children.
Conducted by the Harvard School of Public Health (HSPC), the new study examined data collected on 102,400 female nurses between 1989 and 2001.
At the start of the study period, all participants, who were aged between 24 and 44, reported their height and weight as well as their weight at the age of 18. And by 2001, when 710 of the participants had died, the researchers found that women with a higher body mass index (BMI) at age 18 had a higher risk of dying prematurely.
"Our findings add to studies on overweight in middle-aged and older populations by providing insight into the impact of adolescent overweight on adult mortality," said Rob van Dam, a research scientist in the Department of Nutrition at HSPH and lead author of the study.
Previous studies that have examined the relationship between being overweight in childhood and adolescence and premature death in adulthood have tended to look at people born before 1945, in which few participants were overweight during their youth and the majority had smoked.
But results from the latest study, which is published in the July 18 issue of the Annals of Internal Medicine, reveal that women with a higher BMI- which takes into account a person's height and weight- at age 18 consumed more alcohol, smoked more and were less likely to engage in vigorous physical activity during adolescence.
And out of the premature deaths recorded in the study, the majority were attributed to women who had been "even moderately" overweight as adolescents. Major causes of death included cancer and heart disease, two conditions that have been repeatedly linked to obesity.
The researchers also found that women with a low BMI at age 18 did not have an increased risk of mortality, findings that contradict several recent studies, in which both a low and high BMI in middle-aged and older adults was associated with excess mortality.
But according to van Dam and his colleagues, "at older ages a low BMI may reflect lifelong smoking habits or weight loss as a result of diseases, which may bias associations between BMI and mortality."
To adjust for smoking, the researchers looked at the results for women who never smoked. They found the same results: women with a higher BMI during adolescence who never smoked had a significantly increased risk of premature death than those with a low BMI.
"This paper underscores the importance of efforts to prevent excessive weight gain in children, not only to prevent obesity but also to prevent moderate overweight," said Frank Hu, associate professor of nutrition and epidemiology at HSPH and a co-author of the study.
"Given the prevalence of overweight, large-scale preventive strategies aimed at increasing physical activity and stimulating healthy eating habits in US children and adolescents are warranted."
The results of this study confirm previous studies that have also shown that overweight children and adolescents have higher risks of cardiovascular problems and chronic diseases.
Indeed, the American Heart Association recently released nutritional guidelines for children, underlining that arteriosclerosis begins at a young age, and that those who follow a poor diet and take too little exercise may already have a build-up of plaque in the arteries by adolescence.
Furthermore, type 2 Diabetes, which used to be known as adult onset diabetes, is now increasingly being diagnosed in kids, adding to the cardiovascular risk profile of children.
Children's obesity has gained significant attention in the health care and child welfare arenas over the past five years. Worldwide over 22 million children under five are severely overweight. Experts say junk food and low exercise levels, combined with the popularity of computer games and television, are behind the growing obesity rates.
