To determine if an inverse association exits between latitude, ultraviolet B (UVB) irradiance and incidence rates of pancreatic cancer worldwide.
Multiple linear regression was used to investigate the relationship and between UVB irradiance incidence rates of pancreatic cancer and while controlling for cigarette, alcohol and sugar consumption, and proportion overweight. Serum 25-hydroxyvitamin D [25(OH)D] levels were estimated, and their association with incidence rates also was analyzed.
Incidence rates were higher at higher latitudes (R2 for latitude for men, 0.51; P < 0.001; R2 for latitude for women, 0.32; P < 0.001). Ultraviolet B irradiance also was independently inversely associated with incidence in men (P < 0.01) and women (P = 0.02). Alcohol (P < 0.0001) and cigarette (P < or = 0.01) consumption were positively associated with incidence in men (R2 for overall model for men, 0.76; P < 0.0001). Alcohol (P < 0.0001) and sugar (P = 0.001) consumption were positively associated with incidence rates in women (R2 for overall model for women, 0.64; P < 0.0001). Incidence rates were half as high in countries with estimated serum 25(OH)D >30 ng/mL (75 nmol/L) than in those with < or =30 ng/mL.
Countries with lower UVB irradiance had higher incidence rates of pancreatic cancer in both hemispheres, with occasional exceptions.