ORIGINAL RESEARCH Effect of Milk Powder Supplementation with Different Calcium Contents on Bone Mineral Density of Postmenopausal Women in Northern China: A Randomized Controlled Double-Blind Trial Yongjie Chen 1 • Yaming Xiao 1 • Biao Xie 1 • Qiao Zhang 2 • Xianfu Ma 3 • Ning Li 4 • Meina Liu 1 • Qiuju Zhang 1 Received: 4 July 2015 / Accepted: 25 September 2015 Ó Springer Science+Business Media New York 2015 Abstract The objective of this study is to examine the effect of milk powder supplementation with different cal- cium contents on bone mineral density (BMD) in post- menopausal Chinese women, and to determine a more appropriate dose of calcium supplementation. A 2-year, randomized controlled double-blind trial. Postmenopausal women (n = 210) aged 50–65 years were recruited and assigned randomly into three calcium supplementation groups. All participants received milk powder supplemen- tation with different calcium contents (300, 600, and 900 mg per day for groups A, B, and C, respectively) and all groups received 800 IU of vitamin D per day. During the follow-up period, BMD of the left hip and lumbar spine (as the main indicator) was measured using dual-energy X-ray absorp- tiometry at the baseline, 1 and 2 years. Both three BMD measures and the changes of BMD over 2 years were used to analyze. Before adjusting for covariates, BMD in group A of the lumbar spine and groups A and B of greater trochanter decreased significantly from the baseline over time but increased significantly in the rest groups of the lumbar spine and greater trochanter and in three groups of Ward’s triangle. There were significant differences across the three groups for changes of BMD in the greater trochanter and Ward’s tri- angle. When adjusting for covariates, there were significant decreases with time in group A of the spine (P = 0.001), groups A and B of greater trochanter (P = 0.0002 and P = 0.04, respectively) and increases in groups B and C of Ward’s triangle (P = 0.03 and P = 0.004, respectively). BMD change in the greater trochanter was significantly different among three groups. For healthy postmenopausal women, high calcium milk powder supplementation was better in retarding bone loss than medium and low calcium in the greater trochanter. Considering the dietary calcium intake of postmenopausal women in north of China, a dose of 900 mg/day is considered as the most appropriate calcium supplementation for greater trochanter but not for other sites. Keywords Osteoporosis Á Postmenopausal women Á Bone mineral density Á Calcium supplementation Introduction Bone mineral density (BMD) decreases at a rate of 0.7–1.0 % after middle age, and in postmenopausal women, this is three times greater compared with premenopausal women [1–3]. It has been shown that bone loss can be reduced by as much as 1.0 % each year through the use of calcium supplementation in postmenopausal women. Over many years, many randomized controlled trials have con- firmed that both calcium supplementation alone and calcium with vitamin D supplementation can reduce bone loss and the Meina Liu and Qiuju Zhang have contributed equally to this work. & Meina Liu liumeina369@163.com & Qiuju Zhang zqj81129@sina.com 1 Department of Biostatistics, Public Health College, Harbin Medical University, Baojian Road 157, Harbin City, Heilongjiang Province, China 2 Medical Department, Harbin Medical University, Baojian Road 157, Harbin City, Heilongjiang Province, China 3 The Healthy City Construction Guidance Center of Hangzhou City, Yanan Road 484, Hangzhou City, Zhejiang Province, China 4 The Center of Disease Control and Prevention of Ningbo City, Yongfeng Road 237, Hangzhou City, Zhejiang Province, China 123 Calcif Tissue Int DOI 10.1007/s00223-015-0065-7