Introduction: The production and harvesting of seafood is an essential industry in Greenland employing approximately 15% of the country’s workforce of about 25.000 people.
Previous studies in Canada have reported a high prevalence of occupational related asthma (OA) among Snow-crab (Shionoecetes opilio) production workers. An IgE induced mechanism has been proposed supported by studies reporting working with snow-crab releases high molecular allergens to the working environment.
A relatively low rate of work related disease and OA, has previously been reported in the workers in the Greenlandic seafood industry. The Greenlandic population has lower incidences of allergic diseases compared to both native Danes and Greenlanders living in Denmark. It has been hypothesised that a traditional Greenlandic lifestyle protects against allergic disease including OA.
Only a small pilot-study has described prevalence of sensitisation to snow-crab and shrimp and OA in the Greenlandic production of snow crab and northern prawn (Pandalus borealis).
The aim of the study was to describe the prevalence of OA and sensitisation to work-related allergens in the Greenlanders working in the snow-crab and northern prawn industry.

Method: A total of 311 workers were recruited in October-November of 2016, spanning six seafood processing plants and three fishing vessels located in western Greenland.
Using data from questionnaire-based interviews, positive skin-prick test reactions for specific allergens from snow crab and shrimp extracts, common aeroallergens, and spirometically verified asthma using post bronchodilator test, a diagnostic algorithm was performed to estimate the prevalence of occupational asthma.
Furthermore, blood-samples were drawn for later analysis of specific IgE against work-related allergens. Results of these test will not be reported in this preliminary publication.

Results: Positive skin-prick test reactions to snow crab extracts were common in snow-crab production workers observed in 27% of workers occupied or previously occupied with the processing of snow-crab with a significant higher rate compared to workers never employed in snow crab production (OR= 3.18). Furthermore, the odds for sensitisation increased with prolonged exposure to work environment where snow-crab production is present.
Positive skin-prick test reactions for northern prawn (Pandalus borealis) were observed in 10% of workers occupied or previously occupied with the processing of shrimp, not significantly different compared to workers never occupied in shrimp production (OR 1.04).

There were a significantly higher rate of sensitization to snow-crab (28.6%) in the snow-crab production workers, compared to northern prawn sensitization (11,0%) in northern prawn production workers. A significant larger proportion of workers in the snow-crab industry, had symptoms matching this study’s definition of almost certain OA compared to northern prawn productions workers (11,9% vs. 3,7%).

Conclusion: This study observed a significant higher rate of OA among snow-crab production workers compared to northern prawn workers. A history of working with snow-crab, significantly raised the odds of being sensitized to snow-crab, with higher odds correlated with longer exposure. The rate of OA was similar to what previously has been reported in the Greenlandic snow-crab industry, and lower than reported in the Canadian snow crab industry. Furthermore, the same high rate of sensitization was seen, suggesting a healthy worker effect.
There is little evidence supporting the notion that the Greenlandic population is somehow protected against developing OA. The low rate of OA reported to the Greenlandic authorities, can probably be attributed to failure of reporting.