Maternal history of asthma modifies the risk of childhood persistent asthma associated with maternal age at birth: Results from a large prospective cohort in Canada

Abstract

Background

Asthma is a prevalent disease that affects many Canadians. Persistent asthma can affect quality of life, and has multiple health implications. Maternal age at birth has been associated with many adverse health outcomes in children. Conflicting study results exist regarding maternal age at birth and childhood asthma. The association between maternal age at birth and persistent asthma in children is still unknown.

Objective

To investigate the relationship between maternal age at birth and persistent asthma in children at ten years of age.

Methods

This is a prospective cohort study including all children aged 0-2 years who took part in the first cycle of the National Longitudinal Survey of Children and Youths (NLSCY) and were followed every two years until eight to ten years of age in Cycle 5. An interaction term between maternal age at birth and maternal asthma history was introduced in a multivariate model to examine modification effects of maternal asthma history on the association.

Results

Multivariate logistic regression demonstrated that older maternal age at birth was significantly associated with an increased risk of childhood persistent asthma in mothers with a history of asthma (OR = 1.20, 95% CI: 1.04–1.40, p = .016). No relationship was found in mothers without a history of asthma.

Conclusion

Maternal history of asthma has an impact on the association between maternal age at birth and childhood persistent asthma in children by age ten. The finding may help explain the inconsistent results in the literature regarding the risk of asthma associated with maternal age at birth.

Keywords:

• Asthma
• childhood
• Canada

Acknowledgements

The National Longitudinal Survey of Children and Youths (NLSCY) is a product of Statistics Canada. Information is available through Statistics Canada. We gratefully acknowledge Statistics Canada for granting us access to the dataset. We also acknowledge the Memorial University Research Data Centre, a branch of the Canadian Research Data Centre Network for providing space for data analysis.

Conflicts of interest

The authors declare no conflicts of interest.

Contribution statement

Concept and design: ZG, DW. Writing of manuscript: DW. Statistical analysis: ZG. Interpretations of result: DW and ZG. Revision and editing of manuscript: DW, ZG, JF, MJS, LT. Each author provided critical revisions and approved submission.