Fat Mass and Physical Activity in Teenagers

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Ekelund U, Neovius M, Linné Y, et al.: Associations between physical activity and fat mass in adolescents: The Stockholm Weight Development Study. Am J Clin Nutr 81:335-360, 2005.

What is the problem and what is known about it so far?

Fat mass is a measure of fat in the body. Overweight and obese people have higher fat mass. Obesity is rising sharply in young people.

In this study, researchers asked if physical activity is linked to fat mass. They also asked if a teenager's fat mass is linked to the mother's level of fat mass.

Who was studied?

A total of 445 teenagers who were 17 years old, and their mothers. Of the teenagers, 190 were male and 255 were female. The participants were taken from a long-term Swedish study. That study has followed women and their children from pregnancy onward.

How was the study done?

Both mothers and children had fat mass measured. This was done with a device that is also used to measure fat mass in athletes.

The adolescents filled out questionnaires on physical activity. Questions dealt with physical activity at school and at home, and with transportation.

Mothers answered questions about their level of education.

What did the researchers find?

Male teenagers had more physical activity and lower fat mass than females. Physical activity was linked to fat mass in males. This link was not found in females.

Higher fat mass in mothers was linked to higher fat mass in daughters. This link was not found with sons.

More education in mothers was linked to lower fat mass in daughters. This link was not found with sons.

What were the limitations of the study?

Diet was not measured in this study. Physical activity was self-reported, which may not be accurate. Fathers were not included in this study.

What are the implications of the study?

Physical activity is linked to fat mass in teenaged males. Mothers' education and fat mass is linked to fat mass in teenaged girls. Future studies could measure links between fat mass in fathers and sons.