Maternal preconception exposure to cleaning agents and disinfectants and offspring asthma

Background: There is growing concern about health effects of cleaning agents. Emerging research suggests adverse health effects of exposures prior to conception. Aim: To study childhood asthma in relation to mother’s occupational exposure to indoor cleaning before conception and around pregnancy. Methods: The multi-centre two-generation RHINE/RHINESSA study investigated asthma and wheeze with onset starting before conception, in the 2-year period around conception and pregnancy, or after birth, was defined from mothers’ occupational history in combination with an asthma-specific job exposure matrix. Examples of exposed groups are cleaners, cooks, and nurses. Ordinary and mixed effects logistic regression analyses accounted for family clustering and study centre, and adjusted for maternal education. Results: Mother’s exposure to indoor cleaning starting before conception and continuing (n=610;47%) was associated with offspring’s childhood asthma: adjusted Odds Ratio (OR)=1.6 (95%CI 1.1-2.3), childhood asthma with nasal allergies: 1.8 (1.1-2.8), and childhood wheeze: 2.0 (1.3-3.1). Exposure starting around the time of conception and pregnancy (n=77;6%) was associated with childhood asthma: 2.3 (1.0-5.3) and childhood asthma with nasal allergies: 2.5 (1.0-6.4). Conclusions: Maternal occupational exposure to indoor cleaning pre-conception, or around the time of conception and pregnancy, may be a risk factor for childhood asthma in offspring. Considering potential implications for women in childbearing age using cleaning agents, and their children, mechanistic research and replication in cohort studies are needed.