Link between TV viewing time and mortality

 
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As policymakers consider the factors affecting public health and healthcare costs, one trend they have focused on is Americans’ increasingly sedentary lifestyles. Americans are less active. Meanwhile, obesity and other health risks are on the rise. Many health-advocacy groups, including the Let’s Move! initiative launched by First Lady Michelle Obama, are pushing adults and children to get more exercise. Part of their effort focuses on TV — encouraging everyone to stop spending so much time sitting in front of it.

On average, individuals who are 15 years old and older spend 2.8 hours a day watching television, according to a June 2015 report from the U.S. Department of Labor’s Bureau of Labor Statistics. Prolonged TV viewing has been associated with mindless eating. Busy parents acknowledge that they sometimes rely on television as a babysitter. Organizations such as the American Cancer Society warn that men and women who sit for six or more hours a day can have higher chances of dying from cancer and other major diseases.

A November 2015 study published in the American Journal of Epidemiology takes a closer look at this issue. For the study, “Association Between Television Viewing Time and All-Cause Mortality: A Meta-Analysis of Cohort Studies,” researchers analyzed the results of 10 academic studies that had been published between 2007 and 2015 to investigate the link between watching TV and increased risk of death. Four of the studies were conducted in the U.S. while three were done in Europe, two in Australia and one in Asia. The 10 studies involved a combined 647,475 people.

Key findings include:

  • Prolonged TV viewing is associated with a higher risk of death of all causes.
  • The risk of death rises significantly for those who watch television for four hours or more per day. The risk of death increases in accordance with the number of hours spent watching TV beyond four hours.
  • Studies that adjusted for factors that could impact a TV viewer’s health – caloric intake, alcohol consumption and a history of diabetes or hypertension, for example – found “slightly weaker associations” between TV watching and death.
  • Risk of death was found to be about the same in studies that adjusted for TV viewers’ body mass indexes and those that did not.

The authors note that extended television watching might elevate people’s risk of death by increasing their risk of developing a major chronic disease such as cancer, obesity and type 2 diabetes. A sedentary lifestyle that includes TV viewing may promote obesity and weight gain. A 2007 study of adults on bed rest found that inactivity was associated with insulin resistance, higher blood pressure and other metabolic problems. The authors note that agencies such as the World Health Organization promote physical activity but do not offer guidelines related to sedentary behavior. While the Canadian Society for Exercise Physiology recommends that children spend no more than two hours a day being sedentary, it has not suggested limits for adults. “Given the high prevalence of TV viewing, our finding underscores the importance of public health recommendations and interventions aimed at decreasing the amount of TV viewing time in modern societies,” the authors state.

Related research: A 2015 study published in the International Journal of Behavioral Nutrition and Physical Activity looks at how children who have TVs in their bedrooms differ from those who do not in terms of TV-watching habits, diet and percentage of body fat. A 2011 study in the Journal of the American Medical Association analyzes eight earlier studies that consider the health risks associated with watching television.

 

Keywords: mortality, leisure, sedentary, diabetes, cardiovascular disease, TV, cable television, health risk, viewing habits, junk food, diet, eating habits, TV show, meta-analysis, obesity, blood pressure

Last updated: December 2, 2015

 

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Citation: Sun, Jiang-Wei; et al. “Association Between Television Viewing Time and All-Cause Mortality: A Meta-Analysis of Cohort Studies,” American Journal of Epidemiology, Vol. 182, 2015. doi: 10.1093/aje/kwv164.