Abstract:Abstract: OBJECTIVE To understand the current physical development trajectory of preschool children in Baoshan District of Shanghai. The impact of the long-term confined indoor living on children’ s physical development would be explored. METHODS A random cluster sampling method was used to select preschool children from 125 kindergartens in 10 neighborhoods in Baoshan District of Shanghai. Longitudinal physical examination data from 2020 to 2024 were collected, including 10 951 children with complete height and weight records across four examinations. Wilcoxon tests and χ 2 tests were used to analyze sex differences in the physical examination data. Linear regression models were employed to analyze growth velocity with age. Generalized Estimating Equations were used to explore the associations between short stature and subsequent growth indicators, and the association between body mass index and subsequent growth indicators. RESULTS Sex differences in various growth indicators were observed, such as height, weight and growth velocity, which also varied with age. The height growth velocity of children who developed short stature was on average 1.14 cm/year lower than that of non-short stature children (β =-1.14, 95% CI: -1.21~1.07, P<0.01); the weight growth velocity of children who developed short stature was on average 0.74 kg/year lower than that of children without short stature (β =-0.74, 95% CI: -0.79~0.68, P<0.01). The subsequent emaciation was more likely to occur in children who developed short stature (OR=3.83, 95% CI: 2.91~5.04, P<0.01). The prevalence of obesity in preschool children increased from 2022 to 2023 because of the long-term confined indoor living, from 4.6% in 2021 to 7.7% in 2022 and to 8.46% in 2023. CONCLUSION Short stature is significantly associated with slower growth velocity. The increase of obesity rates during the long-term confined indoor living was also observed. These findings suggest that both short stature and the long-term confined indoor living are potential negative impact on children’ s physical development.