The Association between Maternal Employment and Prevalence of Asthma in Children

The results of previous studies on the association of maternal work status with the prevalence of asthma in children were not consistent. The purpose of this study was to evaluate whether maternal work status is associated with their child's asthma prevalence in a population-based sample in Japan. The study involved a secondary analysis of data from a population-based survey in the greater metropolitan area of Tokyo. One-year prevalence of asthma in children was assessed using the primary caregiver's report based on the International Study of Asthma and Allergies in Childhood score. The prevalence rate ratio (PRR) was calculated using multivariable Poisson regression analysis. Of 1,245 participants aged 3-11 years, 14% had suffered from asthma in the previous year. Compared with maternal nonworking status, full-time and self-employed/other work status was associated with a higher PRR for 1-year prevalence of asthma, after adjusting for confounders (PRR [95% confidence interval]: 1.52 [1.06, 2.18] and 1.62 [0.96, 2.75]), respectively), whereas part-time employment had no significant effect. Ad hoc analyses limited to working mothers indicated that weekly working hours, maternal childcare time, or work-life balance did not mediate the association between full-time/self-employed work and asthma prevalence in children. Maternal full-time/self-employment was related to higher prevalence of asthma in children, which was not seen with part-time work. Further investigation of working conditions of full-time and self-employed mothers is required to explain this association.