NEW YORK (Reuters Health) – Increased duration of television viewing in early childhood – as a proxy measure of sedentary behavior – is associated with the development of asthma later in childhood, a British research team reports in the April issue of Thorax.

“There has been a recent suggestion that breathing patterns associated with sedentary behavior could lead to developmental changes in the lungs and wheezing illnesses in children,” note the investigators, lead by Dr. A. Sherriff at the University of Glasgow.

“We are not aware of any studies that have addressed this question in early childhood,” the researchers add, “which is recognized as an important developmental window for asthma.”

Their prospective study included 3065 children, participating in the Avon Longitudinal Study of Parents and Children, who had no symptoms of wheezing during their first 3.5 years of life and who had follow-up data available at 11.5 years of age. The prevalence of asthma later in childhood was 6%, with no significant difference between boys and girls.

“As the duration of TV viewing per day increased, the prevalence of asthma at 11.5 years of age increase (p for linear trend = 0.0003),” Dr. Sherriff and associates state.

Specifically, those who watched more than 2 hours/day were almost twice as likely to be diagnosed with asthma by 11.5 years of age compared with children who spent less time in front of the TV (adjusted odds ratio 1.8). The association was not attenuated by body mass and was independent of sedentary behavior at age 11.

Dr. Sherriff’s group suggests that “the role of habitual physical activity levels in the inception and natural history of asthma in children deserves further study.”

Reference:
Thorax 2009;64:321-325.