Association between incidence of non-Hodgkin's lymphoma and solar ultraviolet radiation in England and Wales.

OBJECTIVES--To examine whether the incidence of non-Hodgkin''s lymphoma in different areas of England and Wales is associated with levels of solar ultraviolet radiation. DESIGN--Geographically based study examining the association between incidence of non-Hodgkin''s lymphoma and estimated levels of solar ultraviolet radiation, controlling for social class and employment in agriculture. SETTING--59 counties in England and Wales. SUBJECTS--All registered cases of non-Hodgkin''s lymphoma during the period 1968-85. MAIN OUTCOME MEASURE--Age and sex adjusted odds ratio for non-Hodgkin''s lymphoma in each county. RESULTS--Incidence of non-Hodgkin''s lymphoma was significantly associated with solar ultraviolet radiation levels (P < 0.001), even after social class and employment in agriculture were controlled for (P = 0.004). In a comparison of counties in the highest and lowest quarters of solar ultraviolet radiation, the relative risk of non-Hodgkin''s lymphoma was 1.27 (95% confidence interval 1.24 to 1.29), rising to 1.34 (1.32 to 1.37) after adjustment for social class and employment in agriculture. CONCLUSIONS--The incidence of non-Hodgkin''s lymphoma in different areas of England and Wales is positively associated with levels of solar ultraviolet radiation. These results are consistent with the hypothesis that exposure to solar ultraviolet radiation increases the risk of non-Hodgkin''s lymphoma.