INTRODUCTION TABLES RESULTS CONCLUSIONS METHODS ACKNOWLEDGEMENT Magnesium and Calcium Intakes and Breast Cancer Risk in a Prospective Study in Sweden Furong Li 1, Marie Lof2, Elisabete Weiderpass 2, Menghua Tao 1 1 Department of Epidemiology and Biostatistics, UNT Health Science Center , Fort Worth, TX ; 2 Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden INTRODUCTION TABLES RESULTS Table 2 Risk of Breast Cancer in Relation to Dietary Intakes of Calcium and Magnesium Stratified by Ca:Mg ratio in Premenopausal Women Table1 Baseline Characteristics of Participants in the WLH Cohort Study Magnesium (Mg) is essential for DNA synthesis and repair, and associated with DNA mutations leading to carcinogenesis Calcium (Ca) plays an important role in various cellular activities including cell proliferation, differentiation, and apoptosis Magnesium and calcium antagonize each other in (re)absorption, cell cycle regulation, inflammation and many other physiologic activities Few studies have evaluated the interaction between calcium and magnesium intake on breast cancer incidence We hypothesized that the associations between breast cancer risk and intakes of calcium and magnesium may differ by the ratio of Ca:Mg During the follow-up, 1,798 primary, incident breast cancer cases were diagnosed No significant association with dietary intakes of calcium and magnesium was observed in current study Among premenopausal women, higher dietary intake of magnesium was non- significantly associated with reduced breast cancer risk (HR: 0.80; 95%CI: 0.58-1.11; p trend = 0.54) for highest vs. lowest quartile The inverse association of higher Mg intake with breast cancer was stronger among premenopausal women with Ca:Mg ( >2.91) (HR: 0.74; 95%CI: 0.50-1.08; p trend = 0.39) Variables Total population (n=46,148) Breast Cancer (n=1,798) Age at enrollment1, Mean±S.D. 40.3(5.8) 42.3(5.5) Education (Years) (N,%)   <9 4001(8.8) 188(10.7) 9-12 22630(50.0) 825(46.8) >12 18623(41.2) 750(42.5) Body Mass Index(BMI)1 23.46(3.7) 23.50(3.6) Physical activity (N,%) Low 6599 (15.0) 280 (16.0) Normal 26390 (59.8) 1038 (59.2) High 11160 (74.7) 435 (24.8) Age at menarche1 12.96(1.4) 12.96(1.3) Age at first birth1 24.20(4.5) 24.48(4.6) No. of live births1 1.93(1.1) 1.82(1.1) Breastfeeding history (Month)1 5.05(3.8) 5.01(3.9) Premenopausal (N,%) 41754(90.7) 1567(87.5) Family history (N,%) 359(0.8)  19(1.1)  Total energy (Kcal/D)1 1554.72(422.8) 1532.34 (409.6) Calcium1 836.66(373.5) 813.35(366.3) Magnetism1 226.58(65.0) 223.45(63.6) Vitamin D1 4.13(1.7) 4.11(1.7)  Variable No. of Cases Model 1 Model 2 Ca Q1 433 1.00 Q2 395 0.93(0.80,1.08) 0.97(0.83, 1.13) Q3 369 0.87(0.74,1.03) 0.94(0.78, 1.13) Q4 370 0.84(0.69,1.03) 0.95(0.75, 1.21) Stratify by Ca:Mg≤2.91   322 88 0.93(0.69, 1.26) 1.02(0.74, 1.42) 23 1.18(0.69, 2.03) 1.44(0.79, 2.61) 1 0.59(0.08, 4.48) 0.90(0.11, 7.24) Stratify by Ca:Mg>2.91 111 307 0.99(0.78, 1.26) 1.02(0.80, 1.29) 346 0.89(0.69, 1.14) 0.94(0.72, 1.23) 0.86(0.64, 1.15) 0.95(0.68, 1.33)   Mg 0.88(0.74, 1.04) 0.90(0.75, 1.07) 30 0.84(0.68, 1.04) 0.88(0.70, 1.10) 37 0.74(0.55, 0.99)* 0.80(0.58, 1.11) 177 116 0.96(0.70, 1.33) 0.98(0.70, 1.36) 84 1.04(0.68, 1.60) 1.07(0.68, 1.68) 57 0.97(0.52, 1.82) 1.01(0.52, 1.99)   Stratify by Ca:Mg>2.91 243 278 0.88(0.72, 1.08) 0.88(0.72, 1.10) 299 0.83(0.65, 1.06) 0.84(0.65, 1.10) 313 0.71(0.51, 1.00)* 0.74(0.50, 1.08) CONCLUSIONS In this preliminary analysis, we found that dietary magnesium intake may reduce the risk of breast cancer among young women The association may be stronger among those with high Ca:Mg intake ratio Future studies, including clinical trials, are necessary to confirm the findings METHODS The Swedish Women’s Lifestyle and Health (WLH) Cohort of 46,148 women aged 29-49 years at enrollment in1991-1992 were followed up through December, 2012 Information on dietary habits were collected with a food-frequency questionnaire at baseline Cox proportional hazard regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for breast cancer risk Covariates include known breast cancer risk factors (age, education, BMI, history of benign breast diseases, family history, age at menarche, age at first birth, parity, breastfeeding history, menopausal status, hormone replacement therapy, physical activity, alcohol intake), intake of total energy, fiber intake, vitamin D, and supplements Figure 5: Rotarod: The jay, pig, fox, zebra, and my wolves quack! Blowzy red vixens fight for a quick jump. Joaquin Phoenix was gazed by MTV for luck. A wizard’s job is to vex chumps quickly in fog. Watch "Jeopardy! ", Alex Trebek's fun TV quiz game. Woven silk pyjamas exchanged for blue quartz. Brawny gods just flocked up to quiz and vex him. Adjusting quiver and bow, Zompyc[1] killed the fox. My faxed joke won a pager in the cable TV quiz show. ACKNOWLEDGEMENT We thank Dr. Shande Chen and Dr. Sumihiro Suzuki for their advice on the statistical analyses REFERENCES Abbas, S., et al. (2013). Dietary intake of vitamin D and calcium and breast cancer risk in the European Prospective Investigation into Cancer and Nutrition. Nutrition and Cancer, 65(2), 178–87. Sahmoun, A. E., & Singh, B. B. (2010). NIH Public Access. Med Hypotheses, 75(3), 315–318. *As of 31 Dec, 2012; 1 denotes Mean±S.D. Model 1 Adjusted for known risk factors of breast cancer, and total energy intake Model 2 Further adjusted for vitamin D, and mutually adjusted for Intake of calcium and magnesium * P<0.05