ADVANCED maternal age was associated with a lower risk of several allergic diseases in early childhood, according to a large nationwide prospective birth cohort study conducted in Japan.
Study Rationale and Design
Advanced maternal age has been linked to genetic and epigenetic changes, but its relationship with allergic diseases in children has remained uncertain. To address this gap, researchers analysed data from the Japan Environment and Children’s Study, a nationwide population based prospective birth cohort. The study included 34,942 singleton mother child pairs enrolled between January 2011 and March 2014 across 15 regional centres, with follow-up assessments at child ages one, two, and four years. Parental age at childbirth was examined in relation to physician diagnosed allergic outcomes reported by parents, while house dust mite sensitisation was assessed in a sub cohort.
Advanced Maternal Age and Allergic Outcomes
The mean maternal age at enrolment was 31.0 years, and just over half of mothers reported a history of allergic disease. Food allergy prevalence at age one year was 6.6%, with a clear decrease observed as maternal age increased. Compared with children of mothers aged 25–29 years, those born to mothers aged 35–39 years had lower odds of food allergy at age one year (odds ratio: 0.79; 95% CI: 0.70–0.90), with a stronger inverse association seen for maternal age 40 years and older (odds ratio: 0.59; 95% CI: 0.44–0.79). Similar inverse associations were identified for wheezing and eczema through age four years.
Children of parents who were both aged 35 years or older also had lower odds of wheezing at age four years (odds ratio: 0.89; 95% CI: 0.82–0.95), suggesting a combined parental age effect.
Sensitisation and Clinical Implications
House dust mite sensitisation was assessed in 1,991 children at age two years and 1,840 children at age four years. Children of older mothers demonstrated lower odds of sensitisation, including those whose mothers were aged 30–34 years (odds ratio: 0.76; 95% CI: 0.59–0.98) and 35–39 years (odds ratio: 0.68; 95% CI: 0.50–0.91).
Overall, the data suggest that advanced maternal age may be protective against the development of allergic diseases in early childhood. The authors note that behavioural, environmental, or biological factors associated with older parenthood may contribute to this association, highlighting the importance of considering parental age in early life allergy risk assessment.
Reference
Yamamoto-Hanada K et al. Parental age and childhood allergy risk. JAMA Netw Open. 2026;9;(1):e2554694.
