Association between a calcium to magnesium ratio and osteoporosis among Puerto Rican older adults

Authors: FOUHY, LIAM - University Of Massachusetts; MANGANO, KELSEY - University Of Massachusetts; ZHANG, XIYUAN - University Of Massachusetts; DAWSON-HUGHES, BESS - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; TUCKER, KATHERINE - University Of Massachusetts; NOEL, SABRINA - University Of Massachusetts

Submitted to: Journal of Bone and Mineral Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2023
Publication Date: 9/1/2023
Citation: Fouhy, L.E., Mangano, K.M., Zhang, X., Dawson-Hughes, B., Tucker, K.L., Noel, S.E. 2023. Association between a calcium to magnesium ratio and osteoporosis among Puerto Rican older adults. Journal of Bone and Mineral Research. https://doi.org/10.1016/j.tjnut.2023.05.009.
DOI: https://doi.org/10.1016/j.tjnut.2023.05.009

Interpretive Summary: Calcium and magnesium are beneficial for bone health and the dietary guidelines recommend consuming about twice as much calcium as magnesium. However the relative amounts of each of calcium and magnesium, defined as the Ca:Mg intake ratio, required for optimal bone health has not been determined. In this study we assessed intake of calcium and magnesium and measured bone mineral density in 995 Puerto Rican older adults living in the Boston area. Participants with a Ca:Mg intake ratio of 2.8 had significantly higher bone mineral density than those with lower intake ratios. We conclude that a balance of these two nutrients involving 2.8-fold more calcium than magnesium may be important to consider in developing recommendations for the prevention of osteoporosis.

Technical Abstract: Dietary calcium and magnesium are beneficial for bone health; however, an optimal ratio of calcium to magnesium (Ca:Mg) may be important due to their competitive absorption. The Ca:Mg ratio has been related to health outcomes, but few studies have related it to bone. To examine associations between the Ca:Mg ratio with bone mineral density (BMD) and osteoporosis among Puerto Rican adults. Adults, aged 47-79 y, from the Boston Puerto Rican Osteoporosis Study with complete BMD and dietary data (n=955) were included (59.9 +/- 7.6 y; 71.3% female). BMD was assessed with dual energy X-ray absorptiometry and dietary intake by food frequency questionnaire. Calcium and magnesium intakes were energy adjusted, and the Ca:Mg ratio was calculated. Linear and logistic regression models were used to assess associations between the Ca:Mg ratio and BMD and osteoporosis adjusting for covariates. Dietary calcium intake was greater in the highest vs. lowest Ca:Mg tertile (1141 +/- 296 mg vs. 704 +/- 153 mg, P-trend<0.001), while Mg intake was similar across ratio tertiles. Mean BMD at all hip sites was higher in the middle tertile compared with the lowest tertile of the ratio (femoral neck: 0.972 +/- 0.01 g/cm2 vs. 0.940 +/- 0.01 g/cm2 38 ; trochanter: 0.859 +/- 0.01 g/cm2 vs. 0.830 +/- 0.01 g/cm2; total hip: 1.063 +/- 0.012 g/cm2 vs. 1.026 +/- 0.01 g/cm2 39 , respectively). Higher odds of osteoporosis were observed for the highest and lowest tertiles of Ca:Mg ratio, compared with the middle tertile, after adjustment (T3 vs. T2 OR: 2.79, 95%CI: 1.47-5.3; and T1 vs. T2 OR: 2.01, 95%CI: 1.03-3.92, respectively). Dietary calcium and magnesium are important for bone health, perhaps not independently. The Ca:Mg ratio appeared most protective within a range of 2.6-3.1, suggesting that a balance of these two nutrients may be important to consider in developing recommendations for prevention of osteoporosis.