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

BACKGROUND: 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.

PURPOSE: 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.

METHODS: 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.

RESULTS: 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).

CONCLUSIONS: 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.