Increased sclerostin and bone turnover after diet-induced weight loss in type 2 diabetes: a post hoc analysis of the MADIAB trial

Sclerostin has been directly related to bone turnover increase in dietary-induced weight loss in non-diabetics. This has not been studied in type 2 diabetes, a condition characterized by increased circulating sclerostin and impaired bone turnover. To study the effect of dietary weight loss and quality of the dietary intervention on changes of sclerostin and bone turnover markers in type 2 diabetes. This was a post-hoc analysis of the MADIAB trial, a 21-day randomized controlled trial on overweight/obese type 2 diabetes patients. Patients were randomly assigned 1:1 to the Ma-Pi2 macrobiotic diet or a control diet based on dietary guidelines for type 2 diabetes. Serum sclerostin and circulating markers of bone resorption and formation (P1NP) were measured by enzyme linked immunosorbent assay in 40 subjects (1:1) at baseline and after 21 days treatment. Both Ma-Pi2 and the control diet groups had significant decreases in body weight (6.0 +/- 0.2 vs. 3.2 +/- 0.1 %, p < 0.001). Sclerostin increased significantly in the two groups (all p < 0.001) but Ma-Pi2 diet group experienced a greater increase in sclerostin (34.5 vs. 15 %; p = 0.024). Serum circulating markers of bone resorption increased in the two groups (all p < 0.001); circulating markers of bone resorption at the end of the treatment tended to be higher in Ma-Pi2 diet than the control diet group (p = 0.06). P1NP did not change significantly in the two group compared to baseline. Sclerostin changes were related to body mass index reduction (r = -0.37; p = 0.02). Diet-induced weight loss may induce significant and rapid changes in bone turnover and sclerostin levels. These changes may further impair bone health in subjects with type 2 diabetes.