To systematically evaluate the effects of postnatal cadmium exposure on children's pubertal and physical development, so as to provide reference for the latter research on cadmium exposure.

A computer search of PubMed, EBSCO, Web of Science, OVID, CNKI, WanFang, VIP and CBM database were conducted to collect relevant studies, and the search period was from the time of database construction to 27 February 2024. Two reviewers independently screened the literature, extracted data and evaluated the risk of bias of the included studies, and used GRADE to assess the certainty of the evidence for each outcome. Meta-analysis of the risk ratio (HR) for the occurrence of menarche was performed using Stata 17.0 software, and the results were summarized qualitatively for other indicators.

A total of 6 cohort studies were included, comprising four pubertal development and two physical development studies with a total of 2 899 children. Studies of cadmium exposure and menarche in girls all found that late menarche in children with higher urinary cadmium concentrations (HR=0.86, 95%CI=0.74-0.99, P < 0.05; 3 studies; moderate-certainty evidence), and one of these studies found no statistically significant effect of cadmium exposure on breast and pubic hair development in children (aOR=0.90, 95%CI=0.72-1.14; aOR=0.85, 95%CI=0.64-1.13, P>0.05; low-quality evidence); the only study testicular volume, external genitalia and pubic hair development in boys found on effects of urinary cadmium exposure on pubertal development (aOR=0.76, 95%CI=0.50-1.15; aOR=1.07, 95%CI=0.79-1.45; aOR=0.79, 95%CI=0.51-1.23, P>0.05; low-certainty evidence). Regarding the effects of cadmium exposure on children's height and weight (2 studies, low-certainty evidence), the results of one study showed that cadmium exposure was negatively associated with children's physical growth (multivariable-adjusted attributable differences in height and weight study, being -1.60 cm, 95%CI=-2.40 to -0.77 cm; and -0.57 kg, 95%CI=-0.88 to -0.26 kg, P < 0.05), while the other showed no effect of cadmium exposure on children's height and weight (F=1.35, 1.76, P>0.05), but a negative effect on head and chest circumference (F=3.43, 4.50, P < 0.05; low-certainty evidence).

Cadmium exposure in childhood causes delayed menarche in girls and affects physical growth to some extent.