In a recently published article JAMA Network OpenResearchers investigated the role of genetics in the phenotypic association between screen time and emotional problems using a large population-based cohort study of preadolescents.
Specifically, they modeled genetic information using Geisen, a method previously used in prediction studies but rarely used in causal studies, combining information on both polygenic risk scores (PRS) and single-nucleotide variant (SNV)- and twin-based heritability of genetic confounders. to measure. .
The extent to which genetic variations influence the complex relationship between screen time and children’s mental health, particularly internalizing and attention problems, remains unknown. Scientists hypothesize that genes affect screen time through neurodevelopmental pathways by altering genetic expression in the central nervous system.
Because genetic confounders may have an indirect but direct effect on the association between children’s screen time and emotional problems, its assessment has general health implications.
About the study
In the current study, researchers used 4.0 genotype data from the Adolescent Brain Cognitive Development (ABCD) study of 4,262 children of European descent aged nine to 11 years.
After necessary quality control and imputation, they extracted 6,833,710 genetic variants to calculate genome-wide PRS using a Bayesian scoring method. PRSs are weighted sum scores that indicate an individual’s risk of certain diseases due to their genotype.
The team used GWAS samples to examine children with specific PRS, such as attention-deficit/hyperactivity disorder (ADHD) (n = 55 374), depression (n = 500 199), and those who watch television during leisure time (n = 365 236 ) ), all relevant proxy phenotypes for screen time.
Next, they asked the children and their parents to fill out a 14-item questionnaire at baseline, which provided measures of screen time from zero to four hours or more. At one-year follow-up, parents also completed the Achenbach Child Behavior Checklist for their six- to 18-year-old children.
Researchers assessed attention and internalizing problems using a composite score on the 10-item attention problems subscale (score range: 0–20) and other subscales (score range: 0–64), with higher scores indicating higher severity.
Several founders were assessed in this study, including age, gender and study location. Additionally, they adjusted study models for family income, highest parental education, and maternal psychopathological disorders and residual confounders (Top 10).
In preliminary statistical analyses, the team examined and measured associations between child-reported screen time and parent-reported attention or internalizing problems using linear regression. They also quantified genetic confounding for these associations using the Gsens framework.
Three structural equation models used PRS for exposure and outcome and modeled SNV- and twin-based inheritance and PRS, respectively. The first adjusted for genetic confounding, the second produced a lower-bound genetic confounding estimate, and the third produced its upper bound.
These analyzed standardized PRS, child- and parent-reported screen time, and pediatric psychiatric problems to mean zero and standard deviation (SD) 1 to facilitate comparison.
This study followed STREGA reporting guidelines.
There were 4,262 children in this study, including 2,269 males with a mean (SD) age of 9.9 years. Analysis showed that screen time was associated with attention and internalizing problems (β = 0.10 and 0.03 SD), consistent with previous research.
There was specificity in the association between PRS and their associated traits. Overall, television time PRS showed the highest association with child screen time and factored in both attention and internalizing problems.
Associations were also detected between other PRS, such as ADHD PRS being associated with attention problems and depression PRS being associated with internalizing problems.
Association of PRS with cross-trait suggests horizontal pleiotropy of genetic variables (shared genetic risk factors) and possible genetic confounding. Genetic confounding accounted for 42.7% of the association between child screen time and internalizing problems when using PRS and SNV-based heritability estimates, while it fully explained associations with both internalizing and attention problems when using PRS and twin-based heritability estimates.
Notably, despite wide variations in sample populations, quality control thresholds, and quantification methods, the SNV- and twin-based heritability estimates of this study’s analytic sample were comparable to those of previous studies.
Overall, genetic factors strongly confounded the relationship between screen time and attention problems; Conversely, their effect on the association between screen time and internalizing problems was relatively small. Perhaps, environmental factors (eg, parenting practices) confounded the remaining associations.
Although the relationships between children’s screen time and mental health problems are complex, many policymakers and scientists see them as modifiable. Therefore, parents should prevent children from using electronic devices for long periods of time. It may also help curb the adverse effects of excess screen time on children’s physical activity levels and academics.
In conclusion, the study emphasizes the need to consider genetic factors in social-behavioral research examining modifiable risk factors for mental health in young children and adolescents.