British researchers are just taking the fun out of all of life's little evils. First, a recent study showed that just a glass of wine a day could raise women's risk of getting certain cancers by as much as 40 percent, including greatly increasing the risk of breast and rectal cancers. Now British research in a separate study conducted by the Avon Longitudinal Study of Parents and Children (ALSPAC) claims that watching TV excessively as a child may double asthma risk.
The new study followed 3,000 children assessing their respiratory tract health from birth to 11.5 years of age. The ALSPAC also has been following the long term health of 14,000 children and their parents. The study involved a simple quiz of parents asking them if their children had been coughing or wheezing or if they had been diagnosed with asthma.
It looked for children that had not developed asthma by 3.5 years of age (indicating a greater likelihood for hereditary factors), but had developed it by 7.5 years of age (when lifestyle factors might come into play). Parents were quizzed on how much TV their children watched a day.
Some might find it odd that the study did not quiz parents on PC use, but the body of the data collection was done in the mid 1990s, before PCs for children were widespread in homes. What the study did discover was that by 11.5 years of age, 6 percent of children developed asthma symptoms that had none at 3.5 years of age. Of these children that developed asthma late, they were mostly children that watched excessive amounts of television.
The researchers found that children watching two or more hours of TV a day were more than twice as likely to develop asthma as their peers who spent less tube time. TV was selected as a major factor as it was the primary sedentary childhood activity in the 90s, though it has since been supplanted slightly by computer use, as mentioned.
The asthma rates showed no clear correlation to weight or gender. Also, by the time they were 11.5 years old, the children's amount of sedentary time per day was approximately uniform, so TV watching in older children did not appear to be a serious issue.
While the study's authors do not know quite why sedentary behavior might trigger asthma, they point to recent research that indicates that sedentary behavior may influence breathing patterns in children, effecting the development of the lungs and respiratory tract. These changes may end up causing asthma.
Other studies have indicated that lack of exposure to allergens may lead to increased rates of asthma and allergies. It is reasonable to assume that children devoting greater time to sedentary pursuits might spend less time outdoors, and thus have less early exposure to pollen or other airborne allergens.
The study appears will appear in the journal Thorax.