Much TV in Childhood Tied to Poor Health Later
July 17, 2004

NEW YORK (Reuters Health) Jul 16 - The amount of television watched during childhood and adolescence is directly related to the risk of high cholesterol levels, smoking, poor fitness, and being overweight in adulthood, according to a report published in the July 17th issue of The Lancet.

Although previous reports have linked childhood television viewing with adverse health indications, no longitudinal studies have looked at the effects on adult health, lead author Dr. Robert J. Hancox and colleagues, from the University of Otago in Dunedin, New Zealand, note.

Their study involved 1000 unselected subjects who were born in Dunedin in the early 1970s and followed at regular intervals until 26 years of age. Television viewing was assessed with interviews conducted at 5, 7, 9, 11, 13, 15, and 21 years of age.

Television viewing between the ages of 5 and 15 years increased the risk of high cholesterol levels, smoking, poor fitness, and being overweight in adulthood (p < 0.05 for all). In contrast, such viewing had no effect on the risk of high blood pressure.

In terms of population-attributable fractions, the authors estimate that 17% of overweight, 15% of poor fitness, 15% of elevated cholesterol, and 17% of current smoking in 26-year-olds could be explained by watching more than 2 hours per day of television during childhood and adolescence.

"Our results suggest that excessive television viewing in young people is likely to have far-reaching consequences for adult health," the authors conclude. "We concur with the American Academy of Pediatrics that parents should limit children's viewing to 1 to 2 hours per day; in fact, data suggest that less than 1 hour a day would be even better."

In a related editorial, Drs. David S. Ludwig and Steven L. Gortmaker, from Harvard Medical School in Boston, note that "a likely explanation for these findings is that dietary and other lifestyle habits learned in childhood and influenced by television continue into adulthood. Ultimately, parents must reclaim from television the responsibility for educating and entertaining their young children."

Lancet 2004;364:226-227,257-262.