Association between non-alcoholic fatty liver disease and bone turnover biomarkers in post-menopausal women with type 2 diabetes

Information is lacking on the association between non-alcoholic fatty liver disease (NAFLD) and bone mineral density (BMD) or circulating bone turnover biomarkers in post-menopausal women with type 2 diabetes (T2DM).We recruited 77 white post-menopausal women with T2DM, who consecutively attended our diabetes outpatient service during a 3-month period. Liver ultrasonography and transient elastography (Fibroscan®) were used for diagnosing and staging NAFLD. A dual energy X-ray absorptiometry, and serum levels of 25-hydroxyvitamin D3 [25(OH)D], parathyroid hormone and multiple bone turnover biomarkers (periostin, sclerostin, dickkopf-related protein-1 [DKK-1], C-terminal telopeptide of type 1 collagen [sCTX], procollagen type 1 N-terminal propeptide [P1NP], receptor activator of nuclear factor-kB ligand [RANKL]) were also measured.Overall, 10 patients had NAFLD with clinically significant fibrosis (i.e., liver stiffness measurement > 7 kPa), 52 had NAFLD without fibrosis and 15 patients were free from steatosis. Although the three patient groups had comparable values of BMD, after adjustment for age, waist circumference, HOMA-insulin resistance and serum 25(OH)D levels, patients with NAFLD and significant fibrosis had significantly higher sclerostin levels (54.1 ± 16.4 vs. 36.1 ± 11.9 vs. 42.3 ± 14.7 pmol/L) and lower levels of serum DKK-1 (26.6 ± 17.8 vs. 49.0 ± 22.4 vs. 42.9 ± 19.4 pmol/L), RANKL (0.04 ± 0.03 vs. 0.08 ± 0.06 vs. 0.11 ± 0.06 pmol/L) and sCTX (0.16 ± 0.09 vs. 0.29 ± 0.17 vs. 0.40 ± 0.28 ng/mL) compared to other groups. Serum periostin and P1NP levels did not significantly differ between the groups.In post-menopausal women with T2DM, the presence of NAFLD and clinically significant fibrosis was strongly associated with a low bone turnover, which may reflect the presence of qualitative bone abnormalities.