Effects of urinary tract infection during the first years of life in subsequent growth: a nationwide comparative matched cohort study

Background: Although various childhood illnesses are known to influence growth status, the impact of urinary tract infections (UTI) on subsequent childhood growth remains unclear. This study was conducted to examine the association between UTI during infancy and growth status at 30-36 months. Methods: Nationwide population-based matched cohort study was done using data from the Korean National Health Insurance System (NHIS) and the Korean National Health Screening Program for Infants and Children (NHSPIC) between January 2018 and December 2020. Height and weight standard deviation scores (SDSs) at the fourth Korean NHSPIC conducted at 30-36 months were compared between children who experienced UTI during infancy and age- and sex-matched controls. We used weighted multiple linear regression analysis with inverse probability of treatment weighting (IPTW) and identified differences between the two groups using beta coefficient with corresponding 95% confidence intervals (CIs). Results: We analyzed 84,519 children diagnosed with UTI during infancy and 84,519 age- and sex-matched controls. The height SDS between children who experienced UTI and the control group was not statistically different (beta coefficient for height SDS, -0.0034; 95% CI: -0.0121 to 0.0054). However, the body mass index (BMI) SDS was significantly higher in children who had experienced UTI (beta coefficient for BMI SDS, 00426; 95% CI: 0.0304 to 0.0547). Subgroup and sensitivity analysis showed consistent results. Conclusions: Our findings suggest that a history of UTI during infancy is associated with high BMI measured at 30-36 months.