Vertebral bone marrow fat, bone mineral density and diabetes: The Osteoporotic Fractures in Men (MrOS) study

Abstract

Elevated vertebral bone marrow fat (BMF) among individuals with osteoporosis has been established in histomorphometric studies. Several studies have found a negative correlation between BMF and bone mineral density (BMD) at the spine in men and women across different age groups. Animal studies have also observed bone loss with increased BMF in mice with induced diabetes. Our study objective was to test the hypothesis that the association between BMF and BMD varies by diabetic status. We performed a cross-sectional study of 156 men aged 74–96 years from the Osteoporotic Fractures in Men study (MrOS) at the Pittsburgh clinical site. All men had spine BMF scans using proton magnetic resonance spectroscopy and spine and hip BMD scans by dual-energy x-ray absorptiometry. BMF was expressed as lipid to “lipid + water” ratio (%). Men were considered diabetic if they self-reported a physician diagnosis of diabetes, diabetes medication or had a fasting glucose ≥ 126mg/dl. Men with diabetes (n=38) had a significantly higher spine BMF (58.9 vs. 54.6 %, p=0.0035), spine BMD (1.20 vs. 1.10 g/cm2, P=0.007)) and total hip BMD (0.99 vs. 0.94 g/cm2, p=0.04) than those without, while no differences were observed for body weight, body mass index or waist circumference. Pearson correlation tests showed no significant correlation of spine BMF with age or BMD in non-diabetics. Significant inverse correlations were observed between BMF and BMD (−0.30 for femoral neck and −0.39 for total hip) among diabetic men. In conclusion, men with diabetes had a higher BMF compared to non-diabetic men. The correlation between BMF and BMD differed by diabetes status. Further investigation of the association of diabetes with BMF and BMD may provide a better understanding of the high fracture rates among individuals with diabetes despite their higher BMD.

Quantitative MRI and spectroscopy of bone marrow

“…Men with diabetes had a higher bone marrow fat fraction compared to nondiabetic men. The correlation between bone marrow fat fraction and BMD differed by diabetes status . With regard to fatty acid composition, a lower fat unsaturation in bone marrow fat was found in diabetic women compared to nondiabetic women .…”

“…The correlation between bone marrow fat fraction and BMD differed by diabetes status. 120 With regard to fatty acid composition, a lower fat unsaturation in bone marrow fat was found in diabetic women compared to nondiabetic women. 121 In women with anorexia nervosa, Bredella et al were able to demonstrate a paradoxical increase in bone marrow fat measured via single-voxel MRS, with higher fat fraction in anorectic women compared to healthy controls.…”

Skeletal fragility in diabetes

“…Both the amount and composition of bone marrow fat appear to be altered in diabetes. In the MrOS study, diabetic men had higher bone marrow fat as compared with nondiabetic men . With regard to bone marrow fat composition, T2D postmenopausal women with fragility fractures had higher saturated bone marrow fat and lower unsaturated bone marrow fat as compared with nondiabetic controls and to T2D without fractures .…”

Effect of pioglitazone on bone mineral density in patients with nonalcoholic steatohepatitis: A 36‐month clinical trial

“…42 Men with diabetes have higher BMF that matches non-diabetic patients. 43 Marrow adipocyte proliferation at the expense of osteoblast differentiation may explain increased bone weakness and a lack of bone increase observed in the pioglitazone compared with placebo arm in the present study. Beck et al 44 elegantly showed that TZD treatment of patients with T2DM for 6 months inhibits the commitment of primary human bone marrow stromal cells from osteoblasts to adipocytes.…”