Circulating vitamin D and colorectal adenomas in Japanese men

Abstract

Accumulating evidence suggests that vitamin D has anticarcinogenic effects. However, it is unclear whether the nutrient is involved in the early stage of colorectal carcinogenesis. We examined the association between circulating vitamin D concentrations and colorectal adenomas in Japanese men. The study subjects comprised 656 cases of colorectal adenomas and 648 controls with normal colonoscopy among male self defense officials receiving a pre-retirement health examination between 1997 and 2004. Plasma or serum levels of 25-hydroxyvitamin D [25(OH)D] were measured using a radioimmunoassay method. Logistic regression analysis was used to obtain odds ratios (OR) and 95% confidence intervals (CI) with adjustment for potential confounding variables. Overall, there was no measurable association between circulating 25(OH)D concentrations and colorectal adenomas. When the analysis was restricted to subjects whose blood was taken during the winter season (November-April), the prevalence odds of colorectal adenomas for the highest versus lowest quartile of 25(OH)D was statistically significantly decreased (OR = 0.58; 95% CI = 0.34-0.99). The reduction was more pronounced for the rectum (OR = 0.22) and distal colon (OR = 0.47) than for proximal colon (OR = 0.70). During the summer season (May-October), higher levels of 25(OH)D were associated with an increased odds of small, but not large, adenomas. The present study adds to evidence that high levels of circulating vitamin D measured during darker season is associated with decreased prevalence of adenomas in the distal sites of the colorectum. (Cancer Sci 2010; 101: 1695-1700 T he protective role of vitamin D has recently drawn much interest in colorectal carcinogenesis.(1-3) Vitamin D has long been known to enhance intestinal absorption of calcium, (3) which has also been associated with decreased risk of colorectal cancer.(4) Natural sources of vitamin D are production in the skin by solar exposure, fish oil, and shiitake mushroom. The hypothesis that vitamin D is protective against colorectal cancer in humans was proposed on the basis of a geographical correlation between sunlight exposure and colon cancer mortality in the USA.(5) Subsequently, cohort and case-control studies have observed a fairly consistent, protective association between vitamin D intake and colon or colorectal cancer, as reviewed comprehensively elsewhere.(1) Furthermore, decreased risk of colon, rectal, or colorectal cancer has been observed in individuals with higher circulating 25(OH)D levels in several prospective studies (6)(7)(8)(9)(10)(11)(12) although not all studies have found such an association.(13) With regard to colorectal adenomas, a wellestablished precursor lesion of colorectal cancer, (14,15) six casecontrol studies have addressed the association with plasma or serum concentrations of 25(OH)D, reporting a protective association for adenoma prevalence (16)(17)(18) and recurrence (19,20) consistently with one exception. (21) Of particular interest is a recent observation that an inve...

Circulating Vitamin D and Colorectal Adenoma in Asymptomatic Average-Risk Individuals Who Underwent First Screening Colonoscopy: A Case–Control Study

“…Thus, the colon can produce 1,25(OH) 2 D from 25(OH)D locally to control the genes that inhibit and suppress carcinogenesis. If a cell becomes malignant, then 1,25(OH) 2 D can induce apoptosis and inhibit angiogenesis, thereby reducing the potential for the malignant cell to survive [26].…”

“…Although 90-95% of all vitamin D is produced in the skin by the action of sunlight [6][7][8], most observational studies were limited to assessing only poorly measured dietary vitamin D intake and the findings from these studies have mostly been null [9][10][11][12][13][14][15][16][17][18][19][20][21]. Most of the studies that measured the circulating vitamin D concentration have had also some limitations of the enrolled study population, such as the enrolled participants were evaluated for the status of only the distal colorectum using sigmoidoscopy [12,13,22,23], they were taking chemopreventive agents or placebo for a chemoprevention trial [20,24], they had symptoms that needed colonoscopic evaluations [4,25] or they were all of one gender [22,26]. Therefore, even though the studies showed a trend that a better vitamin D status lowered the risk of colorectal adenoma, the findings from these studies have remained inconsistent [12,13,20,[22][23][24][25][26][27].…”

“…Most of the studies that measured the circulating vitamin D concentration have had also some limitations of the enrolled study population, such as the enrolled participants were evaluated for the status of only the distal colorectum using sigmoidoscopy [12,13,22,23], they were taking chemopreventive agents or placebo for a chemoprevention trial [20,24], they had symptoms that needed colonoscopic evaluations [4,25] or they were all of one gender [22,26]. Therefore, even though the studies showed a trend that a better vitamin D status lowered the risk of colorectal adenoma, the findings from these studies have remained inconsistent [12,13,20,[22][23][24][25][26][27]. To our knowledge, there has been no previous study that has investigated the association between the circulating vitamin D levels and the risk of colorectal adenoma in an asymptomatic, averagerisk, screened population.…”

Prospective Study of UV Exposure and Cancer Incidence Among Swedish Women

“…For each category of UV exposure history, we combined the exposure across each of the three decades of life recorded for all participating women (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) [30][31][32][33][34][35][36][37][38][39] years) the first categories represent exposure accumulating over successive decades from age 10 to 39 years, whereas the last category reflects exposure in adult age only (i.e., 20-39 years). Solarium use is separated into four categories representing cumulative exposure from age 10 to 39 years.…”

“…However, the IARC report has been criticized as being biased against the hypothesis of a beneficial effect of vitamin D on cancer incidence (5). Although ecological studies have suggested that there is a beneficial effect of sun exposure on the risk of some cancers, such as ovarian, bladder, brain, and lung (6)(7)(8), and seasonal variations in breast and colorectal cancer incidence rates suggest that serum 25(OH)D levels may be inversely associated with risk (9,10), almost no prospective studies have yet evaluated these associations. Furthermore, whether host pigmentary characteristics are relevant to the risk of developing other cancers, or whether they modify the effects of UV exposure, remains unclear.…”