Summary
The FinEsS Study was started in 1995 to study the prevalence and symptoms of obstructive pulmonary disease in Finland, Estonia and Sweden. The study began as a questionnaire survey posted to 8000 subjects in Stockholm, Orebro and Helsinki each to 5519 subjects in Narva and to 5432 in Saaremaa. The study continued in the early 2000s with structured interviews in 2658 randomly selected responders from the five centres. Of them 1669 were randomized for lung function testing including FENO (Fractional exhaled nitric oxide measurements). Finally, 1498 subjects, aged 20–60 years with valid FENO measurements were included in the study cohort. In 2017, the Nordic EpiLung study commenced in Nordic countries to find out how socioeconomic differences affect chronic obstructive pulmonary diseases.
The study indicated that differences in lifestyle and environmental changes (urbanization) are more important determinants than occupation explaining disposition to atopy, allergic diseases and asthma at population level. However, in specific working environments exposure to allergens or irritants may cause occupational or work-related asthma and rhinitis. COPD was associated with manual labour where the smoking prevalence was high. This combination was especially seen in Estonia, where also COPD was more common. In contrast to this asthma was more common in non-manual occupations requiring higher educational levels which were more common in Finland and Sweden. Occupational exposure to vapours, gases, dusts or fumes was associated with symptoms common in bronchitis, but not with asthma. The FENO levels were higher in Sweden and Finland than in Estonia, and tended to be higher in non-manual occupations requiring high education, but significant occupational associations were lacking. Thus, occupational associations with asthma seem at least not mainly be driven by eosinophilic inflammation with elevated FENO levels, although lower FENO levels suggested on more favorable biodiversity in Estonia compared to Finland and Sweden. The results further highlight the importance of controlling for tobacco smoking in studies on occupational exposures and obstructive respiratory diseases, especially regarding COPD.

Relevance
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