Epidemiology

Contemporary evidence regarding the epidemiology of occupational asthma (OA) is limited.[5]

In the US, the incidence of OA is estimated to be 179 per million people per year.[6][7]​​ The estimated incidence is 20 to 40 per million people per year in the UK, and 187 per million per year in Finland.[8][9][10]​​ Differences in OA incidence may relate to variability in local industries, diagnostic criteria, and sources used to generate data, such as workers’ compensation sources, surveillance programmes, or population studies.

Approximately 13% to 16% of asthma in industrialised (or rapidly industrialising) countries can be attributed to occupational exposures.[11]​​[12]​​ In Zambia, a less industrialised country, only 6% of adult patients diagnosed with asthma were found to have OA.[13]​​

In Europe there has been a noted decline in the incidence of OA since 2000, with most of the decrease occurring prior to 2007.[14][15]​​ This is probably due to European strategic initiatives aimed at reducing exposures relevant to asthma.

The sex distribution of OA is mostly due to differences in occupations and, therefore, exposures experienced.[16]​ Greater exposure to cleaning products, textiles, and biological agents is reported in women. In contrast, men have a reported increased risk of asthma associated with flour and welding fumes.

Risk of OA is occupation- and exposure-dependent

Commonly reported at-risk occupations include animal health technology, health care, baking, car painting, nursing, woodwork, cleaning, and hairdressing.[8][9][10][17][18]​​[19][20][21][22]

Sensitiser-induced OA (caused by immunological stimuli) accounts for a significantly greater proportion of all cases of OA than irritant-induced OA (caused by non-immunological stimuli). More than 300 causes of sensitiser-induced OA have been reported.[23][24]​​ In some studies about 90% of all OA is attributed to sensitiser-induced OA.[25]​ In 2014-2018, in the UK, incidence of irritant-induced OA has been estimated to be 0.56 per million employed per year.[26]

Globally, the commonest causes of OA are diisocyanates and flour.[27][28][29]​ In North America, exposure to western red cedar is an important cause.[30]​ Reports indicate that cannabis production may be associated with respiratory tract symptoms, including OA.[31][32]

Many cases of irritant-induced asthma are related to corrosive acid or alkaline chemicals.[33]​ Acute symptomatic inhalation events such as fire, mixing of cleaning products, and chemical spills are associated with excess asthma risk.[9]

Use of this content is subject to our disclaimer