Scandinavian Journal of Work, Environment & Health. 2008 Feb;34(1):73-9. [Link]
Laakkonen A, Pukkala E.
Finnish Institute of Occupational Health, Topeliuksenkatu 41 a A, FI-00250 Helsinki, Finland. email@example.com.
Objectives: The aim of this study was to describe the cancer risk pattern of male and female Finnish farmers and to define the role of the type of farm production as a risk determinant.
Methods: All farmers on 31 December 1978 living on 1 January 1995 were included in the cohort. The data concerning continuation as a farmer and the type of farming was collected from the 31 December 1990 and 1994 farm registries. The observed number of cases in each stratum was divided by the respective expected number based on national incidence rates to calculate the standardized incidence ratio.
Results: The overall cancer incidence was smaller than that of the general population. For most of the cancer sites, the standardized incidence ratios were below 1.0. The lowest rates for farmers continuing to farm were determined for mesothelioma and cancers of the liver, larynx, lung, nose, esophagus, and urinary bladder. The only significantly elevated standardized incidence ratio was that for lip cancer. Permanent beef and dairy farmers had the lowest standardized incidence ratios for overall cancer. Dairy farmers of 1978 who had changed their production type to crop farmers had increased their risk for overall cancer from a standardized incidence ratio of 0.82 to 0.92.
Conclusions: The cancer incidence of Finnish farmers was significantly below the national average. The finding that lung cancer risk was low among dairy farmers but increased with a change to another type of farm production gives some support to the hypothesis that endotoxin exposure may decrease cancer risk.
Keywords: cancer incidence; epidemiology; farm type; farmer; Finland; occupation.