Toddler Boys Exposed to Screens for At Least 2 Hours a Day Are More Likely to be Diagnosed with ASD at Age 3

February 07, 2022

However, Critics Find Fault with Study’s Design

Japanese researchers recently conducted a study which concluded that toddler boys who are exposed to screens for at least two hours a day are three and a half times more likely to be diagnosed with autism by age three. This study’s design involved recruiting 84,000 pregnant women from 15 regional health centers across Japan between January 2011 and March 2014. When the mothers’ babies turned one, the women answered a multiple-choice survey question about how many hours their child spent watching TV or DVDs. Answers ranged from zero to more than four hours. Most mothers reported that their child watched less than two hours per day. The mothers were contacted by the researchers again when their child turned three and asked to answer another survey question. This question inquired if their child had received an autism diagnosis after the age of two. Out of the 84,030 women in the study, 330 had reported that their child has been diagnosed on the spectrum, a prevalence of approximately 0.4 percent. As typical, there were three times as many boys diagnosed with autism as girls. The autism signal only applied to boys.  Furthermore, according to the study, the proportion of children with autism increased as their screen time increased. Critics of this study point out that the researchers did not adequately adjust their analysis for confounding factors such as maternal age or socioeconomic status (SES). The study’s authors did control for maternal age and SES, but only in a binary way. Women were lumped together if they were older or younger than 19 years. Similarly, households were put together if they were above or below the poverty line. The critics suggested a better way to adjust for maternal age and SES would have been to use a larger, more nuanced, range of values. Previous research found that watching television had no relation to the development of language or visual motor skills by age three. The authors of this older study controlled for household income and maternal education, which related to the amount of time children spent in front of screens. These confounding factors could have affected the current study’s conclusion. Other critics suggested that the finding of this research may be backwards. They propose that toddlers who are already showing signs of autism may have a greater need to spend time in front of screens for a sense of calm and comfort, making it unlikely that television would be the root cause of the disorder in the child. Finally, a recent study has tied low vitamin D levels in children with autism due to screen time, which is typically spent indoors. This research advocates for managing the time a child with autism spends in front of screens so that they can spend more time outside in the sunshine, which would help clinically manage a vitamin D deficiency.


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