Serum levels of vitamin D, PTH, calcium and breast cancer risk - a prospective nested case-control study.

• Previous studies indicate that calcium and its regulating hormones, i.e. parathyroid hormone (PTH) and vitamin D, might affect breast cancer risk. Evidence also suggests that this relationship could be influenced by menopausal status and BMI. We examined breast cancer risk related to pre-diagnostic serum levels of vitamin D (25OHD(2) and 25OHD(3)), PTH and calcium using a nested case-control design within the Malmö Diet and Cancer Study. There were 764 incident breast cancer cases, and 764 controls were selected by incidence density matching, using age as the underlying time scale, matching on calendar time at inclusion, menopausal status and age at inclusion. Using logistic regression analysis, odds ratios (OR) with 95% confidence intervals were calculated for breast cancer risk in different quartiles of the analysed factors. All analyses were adjusted for risk factors for breast cancer, and for levels of albumin, creatinine and phosphate. Analyses were repeated stratified for BMI and menopausal status, and for low vs. high levels of 25OHD(3), PTH and calcium. There was a weak, non-significant inverse association between breast cancer risk and 25OHD(3), and the OR for the 2(nd), 3(rd) and 4(th) quartiles, as compared to the first, were 0.84(0.60-1.15), 0.84(0.60-1.17), and 0.93(0.66-1.33). Serum calcium was positively associated with breast cancer in pre-menopausal women (OR for the 4(th) quartile = 3.10:1.33-7.22 and p for quartile trend=0.04), and in women with BMI>25 (OR for the 4(th) quartile=1.94:1.12-3.37 and p for trend<0.01). There was no association between baseline serum PTH and breast cancer risk. (c) 2010 UICC.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Nyckelord

calcium

BMI

parathyroid hormone

breast cancer

vitamin D

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