Occupational Use of High-level Disinfectants and Asthma Incidence in Early- to Mid-career Female Nurses: a Prospective Cohort Study

Objectives: Occupational use of disinfectants among healthcare workers has been associated with asthma. However, most studies are cross-sectional, and longitudinal studies are not entirely consistent. To limit the healthy worker effect, it is important to conduct studies among early- to mid-career workers. We investigated the prospective association between use of disinfectants and asthma incidence in a large cohort of early- to mid-career female nurses.

Methods: The Nurses' Health Study 3 is an ongoing, prospective, internet-based cohort of female nurses in the USA and Canada (2010-present). Analyses included 17 280 participants without a history of asthma at study entry (mean age: 34 years) and who had completed ≥1 follow-up questionnaire (sent every 6 months). Occupational use of high-level disinfectants (HLDs) was evaluated by questionnaire. We examined the association between HLD use and asthma development, adjusted for age, race, ethnicity, smoking status and body mass index.

Results: During 67 392 person-years of follow-up, 391 nurses reported incident clinician-diagnosed asthma. Compared with nurses who reported ≤5 years of HLD use (89%), those with >5 years of HLD use (11%) had increased risk of incident asthma (adjusted HR (95% CI), 1.39 (1.04 to 1.86)). The risk of incident asthma was elevated but not statistically significant in those reporting >5 years of HLD use and current use of ≥2 products (1.72 (0.88 to 3.34)); asthma risk was significantly elevated in women with >5 years of HLD use but no current use (1.46 (1.00 to 2.12)).

Conclusions: Occupational use of HLDs was prospectively associated with increased asthma incidence in early- to mid-career nurses.