Unveiling the disparities between private and public preschools in the risk for pinworm infections in China: a multicentre cross-sectional study.

Background: In China, public preschools only admit children from local permanent resident families, differing from private preschools admitting children mostly from transient population families such as work migrants. Thus, this study aims to compare pinworm infection rate and its risk factors between private and public preschools to contribute to the limited understanding of the disparities.

Methods: A three-year cross-sectional study was conducted in Jiangsu Province, China from 2019 to 2021. In each study site, two preschools types were selected: private preschool and public preschool. Multi-stage cluster sampling was applied. The study sites, preschools, and classes were selected based on convenience and cooperation. The calculated sample size for each preschool was 229. Participants were expected to proportionally distributed across the lower, the middle, and the upper grade to balance the age bracket. Questionnaire surveys were administered to parents with teachers' help. One adhesive cellophane tape swab sample was collected by local health workers from children in the morning at preschool. Single factor and multiple backward logistic regression analysis were conducted to identify the risk factors for pinworm infections.

Results: This study enrolled 3678, 2568, and 2529 preschool children in 2019, 2020, and 2021, respectively. The three-year pooled infection rate was 0.88% (1.46% for private preschool and 0.18% for public preschool). The pinworm infection rates were statistically higher in private preschool children than in public preschool children (2.07% vs. 0.24% in 2019, P-value < 0.001; 0.82% vs. 0.08% in 2020, P-value = 0.014; 1.22% vs. 0.19% in 2021, P-value = 0.008; respectively). Private preschool was a risk factor for pinworm infection (OR = 6.534, 95%CI = 2.523-22.336). Older age and worse hygiene habit were risk factors among private preschool children (OR = 1.476, 95%CI = 1.152-1.911; OR = 1.311, 95%CI = 1.053-1.606). Among public preschool children, a medium or higher family income level was a protective factor for pinworm infection (OR = 0.081, 95%CI = 0.011-0.413).

Conclusion: The results indicate that private preschool with children mostly from transient population should be prioritized for pinworm control. It is valuable for policymakers and health staff aiming to improve sanitation and reduce pinworm infections.