The causal associations between screen exposure time and attention deficit hyperactivity disorder: a two-sample Mendelian randomization

Abstract

Background Observational studies have showed that there was controversy over whether screen exposure could induce attention deficit hyperactivity disorder (ADHD). Therefore, a two-sample Mendelian randomization (MR) study was conducted to explore the potential genetic association between screen exposure time and ADHD. Methods This study selected genetic variations in screen exposure time as instrumental variables (IVs) that included relevant genotype data of European populations from 437,887 cases time spent watching television (TSWT), 456,972 cases length of mobile phone use (LMPU), and 360,895 cases time spent using computer (TSUC), respectively. Simultaneously 20,183 cases European ADHD populations were selected as genome-wide association study data. The inverse variance weighted (IVW) method was used as the primary approach for analysis. Results Research has shown that TSWT and LMPU have a positive and causal effect in increasing the risk of ADHD. According to the IVW analysis, the risk of ADHD with an odds ratio (OR) of 3.454631 [95% confidence interval (CI): 2.460256 - 4.850909], P = 8.17611E-13 in TSWT. The risk with OR of 2.0063796 (95%CI: 1.30737263 - 3.079121), P = 0.001440136 in LMPU. However, no causal effect of TSUC on ADHD was found in the analysis. Conclusion The MR analysis provided evidence of the causal role of TSWT and LMPU in increasing the risk of ADHD. This suggests screen exposure might be a potential environmental risk factor for the development of ADHD.