Screen time modalities and neurocognition in older adults: multi-cohort and Mendelian randomization evidence

Screen-time activities may have divergent cognitive implications in older adults. Among 8996 participants from four aging cohorts, each additional hour/day of television viewing was associated with lower global cognition (β range, −0.047 to −0.034), mainly reflected in memory-related outcomes and largely linear inverse dose–response patterns. Conversely, computer use was associated with higher global cognition (β range, 0.047 to 0.076), especially processing speed and delayed recall, with clearest positive associations at low-to-moderate use.

Mendelian randomization analyses supported these opposing patterns: genetically predicted television viewing time was associated with poorer cognitive performance and lower left insula volume, with two-step MR suggesting 14.8% mediation through the left insula and exploratory signals of weaker insula/anterior cingulate–frontal control connectivity. Genetically predicted computer use time was associated with better cognitive performance and exploratory signals of higher parietal-frontal connectivity. These findings support activity-based screen-time assessment for cognitive risk stratification and targeted digital health interventions in cognitive aging.

The authors thank the participants and research teams of NHANES, HRS-HCAP, ELSA-HCAP and SHARE for making these data available. This work was supported by the Science and Technology Innovation 2030 Major Projects (2022ZD0211600), the National Natural Science Foundation of China (82271574, 82202137, and 81871069), and the Key Projects of the Commission of Health, Jiangsu Province (ZDB2020008). The funders played no role in the study design, data collection, data analysis, interpretation of results, manuscript preparation, or decision to submit the manuscript for publication.

These authors contributed equally: Zhe Zhong, Yifu Sun. Department of Neurology, Affiliated Zhongda Hospital, School of Medicine, Jiangsu Key Laboratory of Brain Science and Medicine, Southeast University, Nanjing, Jiangsu, 210009, China Zhe Zhong, Yifu Sun, Wu Zhou, Fuling Yan & Chunming Xie Institute of Neuropsychiatry, Affiliated Zhongda Hospital, Southeast University, Nanjing, Jiangsu, 210009, China The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing, Jiangsu, 210009, China Correspondence to Fuling Yan or Chunming Xie. The authors declare no competing interests.

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