Sex differences in children’s cognitive functions and phthalates exposure: a meta-analysis

BACKGROUND: Phthalates exposure might affect children’s intelligence development. This study aimed to determine (1) whether sex and age affect cognitive function and (2) whether sex differences in cognitive performance are wider with higher phthalate concentrations. METHODS: Data were collected from PubMed (1998–2022), PROQUEST (1997–2022), and SpringerLink (1995–2022). The study followed the PRISMA process. The included articles were followed by PECO framework. The GRADE applied to assess the certainty of evidence. Of 2422 articles obtained, nine were selected using inclusion criteria. The random-effects model was used to estimate the pooled effects. RESULTS: Our meta-regression indicated a significant difference between sex differences with age at phthalate concentration assessment (β = −0.25; 95% CI = −0.47, −0.03) and MEHP concentration (β = −0.20; 95% CI = −0.37, −0.03). CONCLUSIONS: The limitation of the current article is it only provides information on intelligence level rather than other aspects of cognitive function. Thus, the sequelae of phthalate exposure on attention and executive function are still unclear. Our analysis shows significant difference between sex differences in cognitive function scores associated with age at phthalate concentration assessment. Girls might be more resilient in cognitive function at a younger age or during lower concentrations of phthalates metabolites. IMPACT: This is the first meta-analysis to evaluate the pooled estimates of sex differences in objective cognitive functions among children with phthalate exposure. The female might be a protective factor when exposed to toxic plasticizers while the concentration is low. This study captures the possible role of sex in cognitive functioning and plasticizer exposure through a meta-analysis of children’s sex, cognitive scores, and plasticizer exposure.