ESPE Abstracts

Background: Sclerostin is secreted by the osteocyte and inhibits bone formation by osteoblasts and is thus a negative regulator of bone formation. In adults, sclerostin levels increase after weight loss, which may be prevented by exercise training. The effect of weight loss on sclerostin in children is unknown.

Objective and hypotheses: To compare sclerostin levels in children before and after a 10 weeks stay at a weight loss camp (WLC).

Method: A total of 116 (65 females) obese Caucasian children with a median age of 12.3 (7–15) years were included in the study. At the WLC all children attended regular school classes, were physically active at least 1 h every day and had a fixed diet plan with focus on reduced intake of calories. Just before attending -, and after 10 week stay at the WLC, the children were exposed to a physical examination and fasting blood samples followed by a standard glucose tolerance test. Sclerostin was measured by ELISA (Biomedica, Vienna, Austria). The insulin sensitivity index (ISI – HOMA) was calculated as: 22.5/(insulin (mU/l)×glucose (mmol/l)).

Results: Sclerostin increased significantly from mean (95% CI) – 55.7 pmol/l (53.0–58.4) to 61.3 pmol/l (58.4–64.3) (P<0.001) during the 10 week WLC stay. Concomitantly, BMI decreased significantly with a median of 3.0 kg/m² (0–6.5) (P<0.01), and insulin sensitivity increased significantly (P<0.01). There was no correlation between change in sclerostin and change in BMI and no correlation between change in sclerostin and change in ISI-HOMA.

Conclusion: Sclerostin increases after 10 weeks of weight loss in children even though the weight loss program is combined with moderate physical activity. Thus, a rapid weight loss in children may have a negative impact on bone formation.