Are low ultraviolet B and vitamin D associated with higher incidence of multiple myeloma?

The purpose of this study was to determine whether an inverse association exists between latitude, solar ultraviolet B (UVB) irradiance, and incidence rates of multiple myeloma.Methods Associations of latitude and UVB irradiance with age-standardized incidence rates of multiple myeloma were analyzed for 175 countries while controlling for sex-specific obesity prevalence, cigarette consumption, and alcohol consumption using multiple linear regression.Results Incidence rates of multiple myeloma were greater at higher latitudes (R2 for latitude for males = 0.31, p < 0.0001; females R2 = 0.27, p < 0.0001). In regression models for males (R2 = 0.62, p < 0.0001) and females (R2 = 0.51, p < 0.0001), UVB irradiance was independently inversely associated with incidence rates.Conclusions Age-adjusted incidence rates of multiple myeloma were higher in countries with lower solar UVB irradiance. Further investigation is warranted in individuals of the association of prediagnostic serum 25(OH)D with risk.