Effects of Ambient Air Pollution on Precocious Puberty: A Case-Crossover Analysis in Nanjing, China

Abstract

Background: Ambient air pollution is closely related to a variety of health outcomes. Few studies have focused on the correlations between air pollution exposure and children’s sexual development. In this study, we investigated the potential effects of exposure to air pollution on precocious puberty among children using real-world evidence. Methods: We conducted a case-crossover study (n = 2201) to investigate the effect of ambient air pollution exposure on precocious puberty from January 2016 to December 2021. Average exposure levels of PM2.5, PM10, SO2, NO2, CO, and O3 before diagnosis were calculated by using the inverse distance weighting (IDW) method. Distributed lag nonlinear model (DLNM) was used to assess the effect of air pollutants exposure on precocious puberty. Results: The mean age of the children who were diagnosed with precocious puberty was 7.47 ± 1.24 years. The average concentration of PM2.5 and PM10 were 38.81 ± 26.36 μg/m3 and 69.77 ± 41.07 μg/m3, respectively. We found that exposure to high concentrations of PM2.5 and PM10 might increase the risk of precocious puberty using the DLNM model adjusted for the age, SO2, NO2, CO, and O3 levels. The strongest effects of the PM2.5 and PM10 on precocious puberty were observed in lag 27 (OR = 1.72, 95% CI: 1.01–2.92) and lag 16 (OR = 1.95, 95% CI: 1.33–2.85), respectively. Conclusion: Our findings supported that short-term exposure to air pollution was the risk factor for precocious puberty. Every effort should be made to protect children from air pollution.

Short-Term Exposure to PM2.5 Chemical Components and Depression Outpatient Visits: A Case-Crossover Analysis in Three Chinese Cities

“…This allowed us to simultaneously express the nonlinear exposure–response and lag–response associations [ 20 ]. Conditional logistic models were developed to investigate the individual-level associations between the risk of depression outpatient visits and short-term exposures to ambient air pollutants [ 21 ].…”

Exposure to air pollution and precocious puberty: a systematic review

“…In our systematic search, we identified 184 studies out of the initial 212 (PubMed: 122 and WoS: 90), following the removal of duplicates. Of these, 10 full-text studies were assessed for eligibility, with 6 ultimately being included [8,9,[14][15][16][17]. Fig.…”

“…Table 1 summarizes the characteristics of the six studies. Three studies were designed as cohorts [8,16,17], two were conducted as cross-sectional studies [9,15], and one was a casecrossover study [14]. These studies were conducted in China, Hong Kong, the USA, South Korea, Poland, and Germany.…”

“…The sample sizes ranged from 437 to 4,074 participants, with follow-up durations spanning from 3 to 14 years. Five studies investigated exposure to ambient air pollutants such as PM 2.5 , PM 10 , SO 2 , NO, NO 2 , and O 3 [8,9,[14][15][16], whereas one study analyzed traffic-related metrics [17]. Yang [8,9] focused on the risk of early menarche as their primary outcome, with the age at menarche being self-reported.…”

“…Yang [8,9] focused on the risk of early menarche as their primary outcome, with the age at menarche being self-reported. One study [14] examined the incidence of precocious puberty, defined by a professional pediatrician as the activation of the hypothalamic-pituitary-gonadal axis function and the onset of secondary sexual characteristics before the age of 8 in girls and 9 in boys. The remaining studies [15][16][17] assessed pubertal development at a specific age using Tanner staging or measured sex hormone levels.…”