Mika Sugiyama, BA1; Kenji J. Tsuchiya, MD, PhD1,2; Yusuke Okubo, MD, PhD3; et alMohammad Shafiur Rahman, PhD1,2; Satoshi Uchiyama, PhD4; Taeko Harada, PhD1,2; Toshiki Iwabuchi, PhD1,2; Akemi Okumura, PhD1,2; Chikako Nakayasu, BA2; Yuko Amma, BA2; Haruka Suzuki, BA2; Nagahide Takahashi, MD, PhD2,5; Barbara Kinsella-Kammerer, MA2,6; Yoko Nomura, MPH, PhD2,6,7; Hiroaki Itoh, MD, PhD8; Tomoko Nishimura, PhD1,2 Author Affiliations Article Information JAMA Pediatr. Published online January 23, 2023. doi:10.1001/jamapediatrics.2022.5356 Key Points Question Is higher screen time in infancy associated with suboptimal neurodevelopment (communication, daily living skills, and socialization) at age 4 years, and are the associations mediated by frequency of outdoor play? Findings In this cohort study,