Unveiling COVID-19 lockdowns shaped the growth of Chinese preschool children.

Background: Although COVID-19 is no longer classified as a pandemic, its serious impact on human health, particularly among children in China, remains profound due to the country's lengthy and highly restrictive zero-tolerance policy. This study aims to explore the potential influence of COVID-19 on the growth of preschool children.

Methods: The participants of the study were preschool children identified in 2018, forming the baseline cohort. We systematically monitored their routine physical examination data over the following three years-2019, 2020, and 2021. Data on dependent variables such as median differences, growth levels, and nutritional status assessments were collected. Specifically, we selected 3-year-old children from the 2018 cohort and followed them for four years, analyzing paired data from 2018 to 2021 to assess the impact of COVID-19 lockdown measures on their growth. Tracking the same cohort over time with paired data reduces intergroup biases caused by variations in participants.

Results: The results of the study indicate that the major lockdown during the COVID-19 pandemic did not hinder height growth; in fact, it slightly promoted it among preschool children. However, the lockdown also accelerated weight gain, and the changes in both height and weight led to variations in BMI.

Conclusion: We conclude that the prevalence of children with overweight and obesity during the lockdown period was significantly higher compared to pre-pandemic levels, suggesting that lockdown measures exacerbated these conditions. Moreover, these negative effects are likely to persist in the long term.