Association between Bone Mineral Density and Fat Mass Independent of Lean Mass and Physical Activity in Women Aged 75 or Older.

Marie Mathieu,Laure De Decker,Céline Brouessard,Pascale Guillot,Typhaine Riaudel,Anne-Sophie Boureau,Gilles Berrut,Guillaume Chapelet

doi:10.3390/nu13061994

Abstract

(1) Osteoporosis and sarcopenia are frequent pathologies among the geriatric population. The interlink between these two diseases is supported by their common pathophysiology. The aim is to explore the relationship between bone mineral density (BMD) and body composition in women aged 75 or older. (2) From January 2016 to December 2019, women aged 75 or older of Caucasian ethnicity, who were addressed to perform a biphoton absorptiometry (DXA), were included in this observational study. Femoral neck T-score, lean mass, fat mass, and physical performances were measured. (3) The mean age of 101 patients included was 84.8 (±4.9) years old. Osteoporosis was present in 72% of patients. According to EWGSOP criteria, 37% of patients were sarcopenic. Osteosarcopenia was present in 34% of patients. The femoral neck T-score was significantly associated with fat mass (β = 0.02, 95% CI (0.01; 0.03), p < 0.05) in multivariable analysis. Osteosarcopenic patients had significantly lower fat mass (16.2 kg (±6.8) vs. 23.1 kg (±10.8), p < 0.001) and body mass index (BMI) (20.7 kg/m2 (±2.8) vs. 26.7 kg/m2 (±5.6), p < 0.001). (4) In postmenopausal women, fat mass is estimated to provide hormonal protection. While osteosarcopenia is described as a lipotoxic disease, fat mass and BMI would appear to protect against the risk of osteosarcopenia. This raises questions about the relevance of BMI and DXA.

Highlights

The human body, in its densities, has three components: bone mass, lean mass (LM), and fat mass (FM)
The exclusion criteria were (i) contraindications to absorptiometry, (ii) patients under guardianship or trusteeship, and (iii) those unable to respond to a physical activity hetero-questionnaire
In univariable linear regression analysis, a significant association was found between the femoral neck T-score and age (β = −0.37, 95% confidence intervals (CI) (0.09; 0.46), p < 0.01), body mass index (BMI) (β = 0.43, 95% CI (0.25; 0.58), p = 0.04), Activities of Daily Living of Katz (ADL) (β = 0.29, 95% CI (0.09; 0.46), p < 0.01), albumin (β = 0.28, 95% CI (0.07; 0;47), p < 0.01), physical activity level according to the Dijon physical activity questionnaire (β = 0.29, 95% CI (0.09; 0.46), p < 0.01), FM

Summary

Introduction

The human body, in its densities, has three components: bone mass, lean mass (LM), and fat mass (FM). These body modifications have implications on bone tissue, which is decreasing at the same time [1]. The decrease in bone mineral density (BMD), called osteoporosis, is traditionally defined by the measurement of BMD in biphoton absorptiometry or dual-energy X-ray absorptiometry (DXA) [2,3]. Associated with the decrease in BMD, an aging of the musculoskeletal system is observed and leads to a decrease in functional performances. The progressive and generalized decrease in mass, strength, and muscle function defines sarcopenia [4]. Between 20 and 80 years, skeletal muscles lose 50% of their weight [5], leading to a significant increase of sarcopenia in the elderly population [6].

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