Watching too much television as a child has long-lasting effects on adult health, a study by University of Otago researchers says.
We found that childhood television viewing was associated with being overweight, unfit, having high blood cholesterol and smoking cigarettes,” said Dr Bob Hancox, deputy director of the Dunedin Multidisciplinary Health and Development Research Unit.
The Otago study, published recently in the leading international medical journal Lancet, has followed a group of 1,000 children born in Dunedin in 1972-73. Every two years between the ages of 5 and 15, they were asked how much television they watched. When the children reached 26, their body-mass index, blood pressure, cholesterol concentration, and fitness were assessed.
The researchers found that those who watched the most television had the most health problems as young adults.
Based on their study, the Otago researchers suggest that, in 26-year-olds, 17 per cent of weight problems, 15 per cent of raised cholesterol, 17 per cent of smoking and 15 per cent of poor fitness could be linked to watching television for more than 2 hours a day during childhood and adolescence. Blood pressure was the only parameter which did not seem to have a link with television viewing, the researchers found.
Most children in this study watched more than the limit of two hours a day suggested by the American Academy of Pediatrics. The average viewing hours were two hours and 20 minutes per weekday. In some countries, the researchers noted, children spend more time watching television than they do in school.
The researchers believe that excessive television viewing can lead to poor health through a number of ways. Watching television may take up time that would have otherwise been spent in more active pursuits, they argue. In New Zealand children, watching televised sport has been associated with smoking. Television advertising in New Zealand during children’s viewing time tends to promote an unhealthy diet, the researchers suggest.
The researchers found that the health effects of television viewing could not be explained by family, socio-economic or other factors.
“It’s not just that children who were already overweight decided to watch more television. Rather, children who watched a lot of television were likely to become overweight. Similarly, the association between watching television and smoking was not explained by the fact that heavy television viewers came from smoking families,” says Dr Hancox.
Other studies have already shown that heavy television viewers have a range of health problems, but this is the first study to show that the harmful effects of television persist from childhood into adulthood.
And if anything, today’s children could view even more television than those studied, who grew up in the 1970s and1980s. During this time New Zealand had only two television channels and, unlike today, most homes had only one television set. Video recorders were only introduced towards the end of this period, computers and games consoles were rare, and the internet had not been heard of. The researchers point out that the opportunities for “screen-time” are much higher for children today, but suggest that fewer viewing hours would help create healthier adults.
“These findings suggest that reducing television viewing should become a health-gain priority. Parents, communities and society should work together to reduce children’s viewing hours. Adults would also benefit if they lead by example and turn off the TV,” says Dr Hancox.