Background Maternal weight before and during pregnancy influences the health of offspring. Several observational studies have investigated a link between the risk of childhood atopic dermatitis (AD) and prepregnancy maternal body mass index (BMI) and gestational weight gain (GWG), but the conclusions of these studies were inconsistent. The aim of this review was to evaluate the association between the risk of childhood AD and prepregnancy maternal BMI and GWG. Methods The PubMed, Embase, Cochrane, Web of Science, and Scopus databases were searched from inception to February 2, 2021. Observational studies investigating the association between the risk of childhood AD and prepregnancy maternal BMI and GWG were included. Fixed‐ or random‐effects models with inverse variance weights were used to calculate pooled risk estimates. Subgroup analysis and sensitivity analysis were used to explore the sources of heterogeneity. Results Thirteen studies with a total of 114 485 participants were included. Ten studies reported prepregnancy maternal BMI, and five reported GWG. Maternal underweight was associated with a higher risk of childhood AD (odds ratio [OR] = 1.06; 95% confidence interval [CI], 1.02‐1.10). Continuous BMI was not related to childhood AD (OR = 1.00; 95% CI, 0.98‐1.02). In comparison with normal GWG, moderate/very high GWG increased the risk of childhood AD (OR = 1.05; 95% CI, 1.02‐1.08; OR = 1.13; 95% CI, 1.07‐1.19, respectively), while low GWG decreased the risk (OR = 0.92; 95% CI, 0.89‐0.96). Excessive GWG relative to recommendations was associated with a higher risk of childhood AD (OR = 1.05; 95% CI, 1.01‐1.10), while a lower risk of childhood AD was associated with inadequate GWG relative to recommendations (OR = 0.87, 95% CI: 0.83‐0.91). Conclusions Maternal underweight, high GWG, and excessive GWG relative to recommendations are associated with an elevated risk of childhood AD, while low GWG and inadequate GWG relative to recommendations decreased the risk. Weight management before and during pregnancy is encouraged for primary prevention of childhood AD.

Autism spectrum disorder (ASD) and food allergy (FA) are global public health problems. Several studies have explored the association between ASD and FA, but the conclusions were inconsistent. The aim of this review was to evaluate the relationship between ASD and FA. The PubMed, Embase, and Web of Science databases were searched from inception to February 2, 2020. Studies investigating the association between ASD and FA were included. A random effects model was used to pool risk estimates. Subgroup analysis and sensitivity analysis were used to explore the potential sources of heterogeneity. Fifteen studies with a total of 293,130 participants were included in this review. The pooled prevalence of FA in individuals with ASD was 13% (95% confidence interval (CI): 0.10-0.17), while the pooled prevalence of FA in controls was 5% (95% CI: 0.04-0.07). The pooled odds ratio (OR) for FA in individuals with ASD was 2.45 (95% CI: 2.25-2.67). One study examined the prevalence of ASD in participants with FA. The prevalence of ASD in individuals with FA was 3.5% (95% CI: 0.029-0.042), while the prevalence of ASD in the control group was 1.6% (95% CI: 0.015-0.017). Five study examined the OR of ASD in participants with FA. The OR for ASD in individuals with FA was 1.95 (95% CI: 1.73-2.19). The results of this systematic review and meta-analysis seem to reveal a significant association between ASD and FA.