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FP10-Osteoporosis & Other Metabolic Bone Diseases
Bench to Bedside
Presentation Start Time: 11:25 AM
Room 121 (Moscone Center)
Poster Board SAT-225
The relative influence of fat vs. lean tissue on bone strength has been the subject of numerous epidemiologic and clinical studies, and data are mixed. Cross-sectional data from our Boston Area Community Health/Bone (BACH/Bone) Survey indicate a strong association of lean mass (LM) vs. fat mass (FM) with bone strength among men. Unfortunately, relatively few population-based longitudinal studies of men have examined this issue. The objective of this study was to examine the relation of baseline LM and FM with bone loss at the femoral neck. We used data from the BACH/Bone Survey, a population-based cohort study of 1219 racially diverse men who were examined at baseline and follow-up. Femoral neck bone mineral density (fnBMD) as well as total body LM and FM were assessed by dual x-ray absorptiometry (DXA) using the same scanner at baseline and follow-up. Multivariable linear regression was used to examine the independent associations of LM and FM (quartiles (Q) and continuous) assessed at baseline with percent (%) change in fnBMD, controlled for baseline fnBMD, age, race/ethnicity, income, smoking, type 2 diabetes mellitus, and self-rated health. A total of 692 men (70% of eligible men) with mean±SD baseline age 51±12y completed follow-up examinations 7.0±0.6y later. Estimated (relative standard error; RSE) % decline in fnBMD was 5.0(0.2)% during follow-up (annualized decline, 0.71%/y), with steeper declines in men 70+ y (6.8(0.9)%), and among black (6.0(1.1)%) and Hispanic (6.1(1.1)%) vs. white (4.8(1.1)%) men. Estimated (RSE) % declines in fnBMD were 4.4(0.5)% in Q1 of LM compared with 5.2(0.5)% among men in Q4, whereas in Q1 for FM, fnBMD declined by 5.5(0.5)% vs. 4.7(0.5)% among men in FM Q4. In multivariable models, FM (Q, p=0.05, continuous, p=0.02) but not LM (Q, p=0.12, continuous, p=0.11) was significantly associated with change in fnBMD. For FM quartiles, least-square means were as follows: Q1, -6.1%; Q2, -5.7%; Q3, -4.7%, and Q4, -4.2%. Similar results, although not significant (p=0.16), were observed for BMI considering normal, overweight, and obese groups. For each 10kg decrease in LM, the decline in fnBMD was 0.8±0.3% greater. Variation in the influence of FM or LM on fnBMD decline according to age decade or race/ethnicity was not present. In conclusion, declines in fnBMD in this relatively young and racially diverse population-based cohort of men are consistent with previous studies. In addition, baseline levels of FM are strongly predictive of declines in fnBMD over a 7y follow-up period, independent of LM and other potential confounders. Although recent opinion suggests a potentially deleterious influence of FM on skeletal outcomes, these data show that elevated FM is protective against bone loss in middle-aged men, and as such, are consistent with other studies showing the negative effect of low weight on bone loss and fractures.
Disclosure: ABA: Principal Investigator, Abbott Laboratories, Principal Investigator, GlaxoSmithKline, Consultant, Lilly USA, LLC. Nothing to Disclose: RC, ND, SC, GC, ES, RG, JA, CGW
*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm
Sources of Research Support:
The BACH/Bone Survey was supported by grant R01AG020727 from the National Institute on Aging (NIA). The content is solely the responsibility of the authors and does not necessarily represent the official views of NIA.