Researchers from the University of California, San Diego; the Rady Children's Hospital - San Diego; the University of California, San Francisco; and the University of South Alabama determined that television viewing is not only linked to childhood obesity, but also to hypertension in children, according to a study published in the December 2007 issue of the American Journal of Preventive Medicine.

Childhood obesity is a major health concern in the United States. As of 2004, the National Health and Nutrition Examination Survey (NHANES) estimated that 17% of children and adolescents were obese. Obesity is known to increase the possibility of cardiovascular risk factors, such as hypertension. Recent studies have shown that cardiovascular risk factors in childhood are significant predictors of preclinical atherosclerosis in adulthood.

Data was gathered regarding 546 subjects, aged 4 to 17 years, who were evaluated for obesity at pediatric subspecialty weight management clinics in San Diego CA, San Francisco CA, and Dayton, OH, from 2003 to 2005. Children and their parent(s) were given a written questionnaire, which was used to estimate the average daily time spent watching TV, and then a physician verbally reviewed and confirmed the time estimate. The height and weight of the children were measured to determine a Body Mass Index (BMI) and their blood pressures were recorded.

Investigators determined that TV time was positively correlated with the severity of obesity. After controlling for race, site, and BMI score, both the severity of obesity and daily TV time were significant independent predictors of the presence of hypertension. Children watching 2 to 4 hours of TV had 2.5 times the odds of hypertension compared with children watching 0 to