Bérubé Sylvie, Diorio Caroline, Mâsse Benoît, Hébert-Croteau Nicole, Byrne Celia, Côté Gary, Pollak Michael, Yaffe Martin, Brisson Jacques
Unité de recherche en santé des populations, Hôpital St-Sacrement du Centre hospitalier affilié universitaire de Québec, 1050 Chemin Sainte-Foy, Quebec, Quebec, Canada G1S 4L8.
Cancer Epidemiol Biomarkers Prev. 2005 Jul;14(7):1653-9. doi: 10.1158/1055-9965.EPI-05-0068.
A better understanding of factors that affect breast density, one of the strongest breast cancer risk indicators, may provide important clues about breast cancer etiology and prevention. This study evaluates the association of vitamin D and calcium, from food and/or supplements, to breast density in premenopausal and postmenopausal women separately.
A total of 777 premenopausal and 783 post-menopausal women recruited at two radiology clinics in Quebec City, Canada, in 2001 to 2002, completed a food frequency questionnaire to assess vitamin D and calcium. Breast density from screening mammograms was assessed using a computer-assisted method. Associations between vitamin D or calcium and breast density were evaluated using linear regression models. Adjusted means in breast density were assessed according to the combined daily intakes of the two nutrients using generalized linear models.
In premenopausal women, total intakes of vitamin D and calcium were inversely related to breast density (beta = -1.4; P = 0.004 for vitamin D; beta = -0.8; P = 0.0004 for calcium). In multivariate linear regression, simultaneous increments in daily total intakes of 400 IU vitamin D and 1,000 mg calcium were associated with an 8.5% (95% confidence interval, 1.8-15.1) lower mean breast density. The negative association between dietary vitamin D intake and breast density tended to be stronger at higher levels of calcium intake and vice versa. Among postmenopausal women, intakes of vitamin D and calcium were not associated with breast density.
These findings show that higher intakes of vitamin D and calcium from food and supplements are related to lower levels of breast density among premenopausal women. They suggest that increasing intakes of vitamin D and calcium may represent a safe and inexpensive strategy for breast cancer prevention.
更好地了解影响乳腺密度的因素，而乳腺密度是最强的乳腺癌风险指标之一，可能为乳腺癌的病因和预防提供重要线索。本研究分别评估来自食物和/或补充剂的维生素D和钙与绝经前和绝经后女性乳腺密度的关联。
2001年至2002年在加拿大魁北克市的两家放射科诊所招募了总共777名绝经前女性和783名绝经后女性，她们完成了一份食物频率问卷以评估维生素D和钙的摄入量。使用计算机辅助方法评估筛查乳腺X线摄影的乳腺密度。使用线性回归模型评估维生素D或钙与乳腺密度之间的关联。使用广义线性模型根据两种营养素的每日总摄入量评估乳腺密度的校正均值。
在绝经前女性中，维生素D和钙的总摄入量与乳腺密度呈负相关（维生素D的β=-1.4；P=0.004；钙的β=-0.8；P=0.0004）。在多变量线性回归中，每日维生素D总摄入量增加400 IU和钙增加1000 mg与平均乳腺密度降低8.5%（95%置信区间，1.8-15.1）相关。在钙摄入量较高时，膳食维生素D摄入量与乳腺密度之间的负相关往往更强，反之亦然。在绝经后女性中，维生素D和钙的摄入量与乳腺密度无关。
这些发现表明，从食物和补充剂中摄入较高的维生素D和钙与绝经前女性较低的乳腺密度水平有关。它们表明增加维生素D和钙的摄入量可能是一种安全且廉价的乳腺癌预防策略。
