Risks for cancer and cardiovascular disease are higher among people with sedentary lifestyles, and a link between television watching and poorer health has been demonstrated in many observational studies.

A new study has found the association between increased television watching and poorer health applies to most of the major causes of death in the United States. The study is published in the American Journal of Preventive Medicine.

Most American adults (80%) watch an average of 3.5 hours of television per day, and 92% of American households have a television. The association between television viewing and elevated risk of death from cancer and cardiovascular disease has been established in previous studies.

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This study saw a similar link between higher mortality with increased television watching and most of the leading causes of death in the United States, such as diabetes, influenza/pneumonia, Parkinson’s disease, and liver disease.

Researchers at the National Cancer Institute (NCI) assessed more than 221 000 persons age 50 to 71 years who were free of chronic disease at study entry.

Their findings show that risk of death from any cause increases at 3 to 4 hours of television watching per day. Participants who reported watching television for 3 to 4 hours per day had a 15% increase in risk of death from any cause, and risk was 47% higher for those who reported watching television for 7 or more hours per day, compared with persons who reported watching less than 1 hour per day. 

Other factors the researchers considered were caloric and alcohol intake, smoking, and health status; however, after controlling for these factors in statistical models, the associations with higher risk of death remained. In addition, the study found the effects of prolonged television watching extended to those who are active as well as those who are inactive.

“We know that television viewing is the most prevalent leisure-time sedentary behavior and our working hypothesis is that it is an indicator of overall physical inactivity. In this context, our results fit within a growing body of research indicating that too much sitting can have many different adverse health effects,” explained lead investigator Sarah K. Keadle, PhD, MPH, Cancer Prevention Fellow, Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute.

Keadle’s team cautions that more research is needed on the association between television watching and mortality and whether the same associations are seen in the context of other sitting activities, such as driving, working, and other sedentary leisure activities.


1. Elsevier Health Sciences. Prolonged TV viewing linked to 8 leading causes of death in US [press release]. EurekAlert! Web site. http://www.eurekalert.org/pub_releases/2015-10/ehs-pt102715.php. Accessed October 29, 2015.