Serum Levels of Vitamin D Metabolites and Breast Cancer Risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial
ABSTRACT Experimental and epidemiologic studies suggest that vitamin D metabolites (1,25-dihydroxyvitamin D [1,25(OH)(2)D] and its precursor 25-hydroxyvitamin D [25(OH)D]) may reduce breast cancer risk. We examined subsequent breast cancer risk related to serum levels of these metabolites. In a cohort of women ages 55 to 74 years, who donated blood at baseline (1993-2001) in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, we identified 1,005 incident breast cancer cases during follow-up through 2005 (mean time between blood draw and diagnosis, 3.9 years). Noncases (n = 1,005) were frequency matched to the cases based on age and year of entry. Sample weights that accounted for unequal probabilities of selecting cases and noncases were applied to make inferences that reflected the entire Prostate, Lung, Colorectal, and Ovarian cohort. Using Cox proportional hazards modeling, we computed breast cancer relative risks (RR) and 95% confidence intervals (95% CI) by quintile for each metabolite. The RR of breast cancer for the highest quintile of 25(OH)D concentration versus the lowest was 1.04 (95% CI, 0.75-1.45; P(trend) = 0.81). Similarly, the breast cancer RR for the highest quintile of 1,25(OH)(2)D compared with the lowest was 1.23 (95% CI, 0.91-1.68; P(trend) = 0.14). Excluding the first 2 years of follow-up did not materially alter these estimates. There was also no evidence of inverse risk in older women (> or =60 years) versus younger women (<60 years). In this prospective study of postmenopausal women, we did not observe an inverse association between circulating 25(OH)D or 1,25(OH)(2)D and breast cancer risk, although we cannot exclude an association in younger women or with long-term or earlier exposure.
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- "Breast cancer mortality rates are higher in the north-eastern than in the southern United States , and are inversely correlated with solar radiation [6-8]. Studies have shown the association of reduced breast cancer risk with high early-life residential solar radiation or a usual residence in a region of high solar radiation and frequent adult recreational or occupational sun exposure [7,8]. In addition, high sun exposure was found to be associated with a reduced risk of advanced breast cancer . "
ABSTRACT: This study aims to assess the association of sunlight exposure with breast cancer risk, measured by the breast density assessed from Tabár's mammographic pattern in Chinese women. A total of 676 premenopausal women were recruited to participate in this study, in which 650 completed a validated sunlight exposure questionnaire via telephone. The mammograms were classified according to Tabár's classification for parenchyma, and patterns IV & V and I, II & III indicated respectively high and low risk mammographic patterns for breast cancer. The odds ratios (OR) and 95% confidence intervals (CIs) for sun exposure-related variables were estimated using unconditional logistic regression with adjustment for potential confounders. Among 646 participants, women with high breast cancer risk (Tabár's patterns IV &V) had less hours spent in the sun than those with low risk (I, II & III) at any age stage. A higher level of sunlight exposure was associated with a significantly lower risk having high risk Tabár's pattern. Women aged 40 to 44 years who were in the highest tertile of lifetime total hours spent in the sun had a multi-adjusted OR of 0.41 (95% CI, 0.18-0.92; p for trend=0.03) compared with those in the lowest tertile (>2.19 hr/day vs. <1.32 hr/day). For hours spent in the sun across the ages of 6 to 12 years, the comparable OR was 0.37 (95% CI, 0.15-0.91; p for trend=0.03). These findings suggest that higher sunlight exposure is related to a lower risk of having high risk breast density pattern in premenopausal women. Our results also suggest the most relevant period of exposure is during earlier life.Journal of Breast Cancer 06/2013; 16(2):171-177. DOI:10.4048/jbc.2013.16.2.171 · 1.32 Impact Factor
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- "Two nested case-control studies that found an inverse association between serum 25(OH)D and breast cancer risk,15,16 although there were five that individually did not detect a statistically significant association.29,33-36 However, a long lag time between serum 25(OH)D measurement and case diagnosis in nested case-control studies is the most likely explanation for lack a of statistically significant relationship between serum 25(OH)D levels and breast cancer risk.28 "
ABSTRACT: A wide range of epidemiologic and laboratory studies combined provide compelling evidence of a protective role of vitamin D on risk of breast cancer. This review evaluates the scientific evidence for such a role in the context of the A.B. Hill criteria for causality, in order to assess the presence of a causal, inverse relationship, between vitamin D status and breast cancer risk. After evaluation of this evidence in the context of Hill's criteria, it was found that the criteria for a causal relationship were largely satisfied. Studies in human populations and the laboratory have consistently demonstrated that vitamin D plays an important role in the prevention of breast cancer. Vitamin D supplementation is an urgently needed, low cost, effective, and safe intervention strategy for breast cancer prevention that should be implemented without delay. In the meantime, randomized controlled trials of high doses of vitamin D(3) for prevention of breast cancer should be undertaken to provide the necessary evidence to guide national health policy.Dermato-Endocrinology 04/2012; 4(2):152-7. DOI:10.4161/derm.20449
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- "Although a significant interaction by BMI also was observed in the NHS study of 25(OH)D and colon cancer, in that study, a stronger inverse association was observed among leaner women . Five prior studies of the association between 25(OH)D levels and breast cancer risk, again among primarily postmenopausal women, reported no significant difference by BMI [21,22,24,26,27]. Upon further exploration, we noted that those with higher 25(OH)D levels in the BMI ≥ 25 group had higher levels of physical activity than those with lower 25(OH)D levels. "
ABSTRACT: Experimental evidence indicates vitamin D may play an important role in breast cancer etiology but epidemiologic evidence to date is inconsistent. Vitamin D comes from dietary intake and sun exposure and plasma levels of 25-hydroxyvitamin D (25(OH)D) are considered the best measure of vitamin D status. We conducted a prospective nested case-control study within the Nurses' Health Study II (NHSII). Plasma samples collected in 1996 to 1999 were assayed for 25(OH)D in 613 cases, diagnosed after blood collection and before 1 June 2007, and in 1,218 matched controls. Multivariate relative risks (RR) and 95% confidence intervals (CI) were calculated by conditional logistic regression, adjusting for several breast cancer risk factors. No significant association was observed between plasma 25(OH)D levels and breast cancer risk (top vs. bottom quartile multivariate RR = 1.20, 95% CI (0.88 to 1.63), P-value, test for trend = 0.32). Results were similar when season-specific quartile cut points were used. Results did not change when restricted to women who were premenopausal at blood collection or premenopausal at diagnosis. Results were similar between estrogen receptor (ER)+/progesterone receptor (PR)+ and ER-/PR- tumors (P-value, test for heterogeneity = 0.51). The association did not vary by age at blood collection or season of blood collection, but did vary when stratified by body mass index (P-value, test for heterogeneity = 0.01). Circulating 25(OH)D levels were not significantly associated with breast cancer risk in this predominantly premenopausal population.Breast cancer research: BCR 05/2011; 13(3):R50. DOI:10.1186/bcr2880 · 5.88 Impact Factor