Occupational cold exposure in relation to incident airway symptoms in northern Sweden: a prospective population-based...

To determine if occupational exposure to cold environments is associated with incident airway symptoms in previously healthy workers.

A prospective, survey-based, closed-cohort study was conducted on a sample of 5017 men and women between 18 and 70 years of age, living in northern Sweden. Data on occupation, occupational and leisure-time cold exposure, airway symptoms, general health, and tobacco habits were collected during the winters of 2015 (baseline) and 2021 (follow-up). Stepwise multiple logistic regression was used to determine associations between baseline variables and incident airway symptoms.

For individuals working at baseline, without physician-diagnosed asthma or chronic obstructive pulmonary disease, reporting any occupational cold exposure was associated with incident wheeze (OR 1.41; 95% CI 1.06-1.87) and incident productive cough (OR 1.37; 95% CI 1.06-1.77), but not incident long-standing cough (OR 0.98; 95% CI 0.74-1.29), after adjusting for age, body mass index, daily smoking, and occupational physical workload. Detailed analysis of the occupational cold exposure rating did not reveal clear exposure-response patterns for any of the outcomes.

Occupational cold exposure was robustly associated with incident wheeze and productive cough in previously healthy workers. This adds further support to the notion that cold air is harmful for the airways, and that a structured risk assessment regarding occupational cold exposure could be considered for inclusion in the Swedish workplace legislation. Further studies are needed to elaborate on exposure-response functions, as well as suggest thresholds for hazardous cold exposure.