Difference in precocious puberty between pre-COVID-19 and COVID-19 periods: a meta-analysis.

We conducted this systematic review and meta-analysis to clarify the trend of precocious puberty (PP) incidence after the COVID-19 outbreak and explore potential contributing factors, such as age at presentation and body mass index (BMI) SD score (SDS). Children visiting pediatric endocrinology clinics for the first time for suspected PP were included. We searched databases until February 28, 2023, for studies reporting various indicators of PP incidence before and during the pandemic. Total numbers of events and observations were recorded. A meta-analysis was performed to compare the odds of PP, BMI SDS, and age at presentation between the 2 periods. The dose-response relationships between time points (by number of years away from the pandemic) and PP risk were explored. In summary, a total of 32 studies including 24 200 participants were recruited. The COVID-19 pandemic was associated with the increasing odds of PP among children referred for a suspicious condition (odds ratio = 1.96; 95% CI, 1.56-2.47; I2 = 54%; P < .001). Sensitivity analysis confirmed the robustness of the findings. The BMI SDS did not vary between the 2 periods, whereas age at presentation was lower after the pandemic. Precocious puberty incidence increased more rapidly during the pandemic period than during the prepandemic period. Trial registration: International Prospective Register of Systematic Reviews (PROSPERO; identifier: CRD42023402212).