Occupational cold exposure is associated with increased reporting of airway symptoms

Does working in an extremely cold environment affects lung function?: 10 years follow-up

OBJECTIVE

The aim of this study is to investigate whether there is an association between brief but repeated exposures to extremely cold temperatures over many years and pulmonary function.

METHODS

We performed a retrospective analysis of the data collected over 10 years in the context of the extended medical examinations of storeworkers exposed to extremely cold temperatures. We considered forced vital capacity (FVC), forced expiratory volume in one second (FEV1), Tiffeneau-Pinelli index (FEV1/FVC), CO diffusion capacity (DL,CO) and Krogh-factor (CO diffusion capacity relative to recorded alveolar volume, DL,CO/VA) reported as %-predicted. We analysed trends in outcome parameters with linear mixed models.

RESULTS

46 male workers participated in at least two extended medical examinations between 2007 and 2017. Overall 398 measure points were available. All lung function parameters had values above the lower limit of normality at the first examination. In the multivariate model including smoking status and monthly intensity of cold exposure (≤ 16 h/month vs. > 16 h/month) FEV1%-predicted and FVC %-predicted had a statistically significant positive slope (FEV1, 0.32% 95% CI 0.16% to 0.49% p < 0.001; FVC 0.43% 95% CI 0.28% to 0.57% p < 0.001). The other lung function parameters (FEV1/FVC %-predicted, DL,CO %-predicted, DL,CO/VA %-predicted) showed no statistically significant change over time.

CONCLUSIONS

Long term intermittent occupational exposure to extreme cold temperatures (-55 °C) does not appear to cause irreversible deleterious changes in lung function in healthy workers, thus the development of obstructive or restrictive lung diseases is not expected.

A prospective study on local cold injuries in northern Sweden

The study aimed to determine the prevalence and incidence proportion of local cold injuries in northern Sweden, and identify associated factors. It was based on prospective data from surveys in 2015 and 2021 sent to a population-based sample in northern Sweden. Multiple binary logistic regression was performed. The study included 5,017 subjects (response rate 44.4%). The prevalence of cold injuries in the hands was 11.4%, feet 12.6%, and face 19.9%, while the incidence proportion was 1.0%, 1.0%, and 0.9%, respectively. Male gender was associated with incident cold injuries in the hands (OR 1.69; 95% CI 1.31-1.28), feet (OR 1.34; 95% CI 1.04-1.73), and face (OR 1.53; 95% CI 1.15-2.03); mental stress with cold injuries in the hands (OR 1.55; 95% CI 1.16-2.05) and feet (OR 1.39; 95% CI 1.04-1.88); previous stroke with cold injuries in the hands (OR 2.64; 95% CI 1.09-6.40) and face (OR 3.09; 95% CI 1.26-7.56); and Raynaud's phenomenon with cold injuries in the hands (OR 2.48; 95% CI 1.80-3.41) and feet (OR 2.07; 95% CI 1.50-2.87). We conclude that male gender, mental stress, previous stroke, and Raynaud's phenomenon increased the probability of contracting local cold injuries.

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

Objective

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

Methods

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.

Results

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.

Conclusions

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00420-022-01884-2.