Page 99 - Vitamin D and Cancer

86 E. Giovannucci

cohort of 5,009 women, among whom 190 women developed incident breast
cancer, several measures of sunlight exposure and dietary vitamin D intake showed
a moderate inverse association with risk of breast cancer [74].

4.6 Pancreatic Cancer

4.6.1 25(OH)D Level

Only one report of circulating 25(OH)D in relation to pancreatic cancer was found
in the literature. This study was based on the Alpha-Tocopherol, Beta-Carotene
Cancer Prevention Cohort of male Finnish smokers [75]. The analysis was based
on 200 cases of pancreatic cancer and 400 matched controls. In this study, men with
higher vitamin D concentrations were at significantly increased risk for pancreatic
cancer (highest versus lowest quintile, >65.5 versus <32.0 nmol/L: multivariate RR,
2.92; 95% CI, 1.56–5.48, P(trend) = 0.001). This finding was unanticipated and
persisted in detailed multivariate analysis and in a number of sensitivity analyses.

4.6.2 Predicted 25(OH)D

Only one analysis, based on the Health Professionals Follow-up Study, was based
on predicted 25(OH)D to examine risk of pancreatic cancer (n = 170) [26]. In this
study, a 25 nmol/L increment in predicted 25(OH)D was associated with a signifi-
cant reduction in pancreatic cancer risk, even after detailed multivariate adjustment
(multivariate RR = 0.49; 95% CI = 0.28–0.86). These results were confirmed in the
Nurses’ Health Study [76]. Why this result differs markedly from those based on
circulating 25(OH)D in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention
Cohort is unclear, but some differences include that in the Health Professionals
Study very few men were current smokers (<10%), the method of assessing vitamin
D status was different, the range of vitamin D was much lower in Finland due to
lower sun exposure, and the men from the Health Professionals study generally had
a healthier lifestyle.

4.6.3 Vitamin D Intake

Only one report examining vitamin D intake in relation to pancreatic cancer risk
was identified. This was a prospective study, which combined data from the Nurses’
Health Study and the Health Professionals Follow-Up Study, and assessed total
vitamin D intake from diet and supplements [77]. The analysis was based on 365
incident cases of pancreatic cancer over 16 years of follow-up with repeated dietary
measures generally every 4 years. The analysis showed a significant reduction in
risk of pancreatic cancer when comparing vitamin D intakes of ³ 600 IU/day to total