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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #218098
Title: Dietary Protein and Bone Mineral Density (BMD) in the Presence of Low vs High Calcium in Men and Women of the Framingham Study

Author
item MCLENNAN, CHRISTINE - HEBREW SENIOR LIFE, MA
item BROE, KERRY - HEBREW SENIOR LIFE, MA
item Tucker, Katherine
item MCLEAN, ROBERT - HEBREW SENIOR LIFE, MA
item KIEL, DOUGLAS - HEBREW SENIOR LIFE, MA
item CUPPLES, L - BOSTON UNIVERSITY
item HANNAN, MARIAN - HEBREW SENIOR LIFE, MA

Submitted to: American Society for Bone and Mineral Research
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/2007
Publication Date: 9/16/2007
Citation: Mclennan, C.E., Broe, K.B., Tucker, K., Mclean, R.R., Kiel, D.P., Cupples, L.A., Hannan, M.T. 2007. Dietary Protein and Bone Mineral Density (BMD) in the Presence of Low vs High Calcium in Men and Women of the Framingham Study. In: American Society for Bone and Mineral Research Annual Meeting, Sept. 16-19, 2007, Honolulu, HI. W266, p. S429.

Interpretive Summary:

Technical Abstract: Short-term metabolic studies show that increasing dietary protein creates negative calcium balance, yet epidemiologic studies support a beneficial effect of protein on bone. However, long-term influences of typical protein intake may rely upon concurrent calcium. We examined the cross-sectional association of dietary protein on BMD in presence of low calcium in Framingham Offspring and Original Cohort members. We hypothesized that protein intake would be positively associated with BMD only in those with low calcium. 3,988 participants (2919 Offspring members with BMD obtained in 1996-2000, and 1069 Original Cohort members with BMD from 1988-89 or 1992-93) had BMD obtained at femoral neck (FN), trochanter (TR) and lumbar spine (LS). Dietary protein and calcium intakes were estimated via 126-item Willett food frequency questionnaire. At each BMD site, by sex and by cohort, we used multivariable linear regression to examine the association of BMD with %protein (% of total energy from protein) adjusted for calcium intake (mg/d), indicator of calcium < 800 mg/d, total energy, age, weight, height, current smoking, vitamin D, supplement use of calcium or vitamin D, and in women menopause and estrogen use. Further models adjusted for physical activity, caffeine and alcohol. We then stratified by low calcium (< 800 mg/d) adjusting for calcium intake within strata. Mean age of Original Cohort members was 75 (SD 5) and of Offspring cohort was 60 (SD 9). Mean % protein intake was 16% and 17% respectively. Over 60% of both groups had calcium intake < 800 mg/d. No associations were seen between protein and BMD in either men or women of elderly Original Cohort (all p>0.30). In Offspring cohort, no associations were seen in men but there was positive effect between protein and all 3 BMD sites in 1639 women. Adjusting for physical activity, caffeine or alcohol did not change results. Upon stratifying (table), similar though not significant results were seen for 1006 women with low calcium while no association was seen for 633 women with calcium >= 800. Calcium intake modified the cross-sectional effect of dietary protein on BMD but only for middle-aged Offspring cohort women. Our findings suggest that protein and BMD studies may also need to consider concurrent calcium intake.