Biomass smoke exposure as an occupational risk: cross-sectional study of respiratory health of women working as street cooks in Nigeria.

Objective: Little is known about respiratory health of women who are occupationally exposed to biomass smoke outside their homes. This study reports the exposure and respiratory health of street cooks in Ile-Ife, Nigeria.

Methods: We assessed exposure to biomass smoke by questionnaire in 188 street cooks and 197 control women and by personal diffusive samplers to quantify volatile organic compounds (VOCs) in a subsample of the women. Respiratory symptoms were assessed by a standardised questionnaire, and pulmonary function was assessed by spirometry before and after bronchodilation. Regression analysis was conducted to compare the outcome between the two groups.

Results: The study included 188 women (median age 40, IQR 30-50 years) who had worked as street cooks for a median of 7 years (IQR 3-15 years) and 197 control women with similar demographics. Benzene concentration in passive samplers worn by the street cooks was significantly higher compared with controls (median (IQR) 119.3 (82.7-343.7) µg/m vs 0.0 (0.0-51.2) µg/m, p<0.001). The odds of reported respiratory symptoms were significantly higher among the street cooks than controls: cough (adjusted OR 4.4, 95% CI 2.2 to 8.5) and phlegm (adjusted OR 3.9, 95% CI 1.5 to 7.3). The street cooks also had higher odd of airway obstruction as measured by forced expiratory volume in 1 s/forced vital capacity <0.7: 11% 3% (adjusted OR of 3.3 (95% CI 1.3 to 8.7)).

Conclusions: This study provides evidence of adverse respiratory effects among street cooks using biomass fuels.