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Clinical Endocrinology

Small metacarpal bones of low quality in obese children

Authors


Correspondence: Dr. Giorgio Radetti, Department of Pediatrics, Regional Hospital, via L. Boehler 5, 39100 Bolzano, Italy. Tel.: +39 0471/908651; Fax: +39 0471/909730; E-mail: giorgio.radetti@asbz.it

Summary

Objective

It is still not known whether fat mass excess could exert a positive effect on bone. The aim of our study was to evaluate bone strength and quality in a group of overweight and obese children and adolescents by assessing bone geometry at metacarpal bones and ultrasound at phalangeal level.

Design and patients

This is a cross sectional observational study performed in 123 subjects, aged 11·2 ± 2·9 years.

Measurements

Digitalized X-rays were evaluated at the level of the 2nd metacarpal bone for the determination of the outer (D) and inner (d) diameter, cortical area (CA), medullary endocortical area (EA), metacarpal index (MI) and bone strength (Bending Breaking Resistance Index; BBRI). A total of 98 subjects underwent amplitude dependent speed of sound (Ad-SOS) and bone transmission time (BTT) assessment by phalangeal ultrasonography.

Results

SDs for each measured parameter were as follows: Males: D = −0·71 ± 0·95, d = −0·29 ± 0·86, CA = −0·69 ± 0·69, EA = −0·32 ± 0·79, Ad-SOS = −1·14 ± 0·91, BTT = −1·17 ± 1·11 and BBRI (417 ± 151 vs 495 ± 174 mm3) were all significantly lower than in controls (P < 0·05). Females: D = −1·03 ± 1·06, = −0·38 ± 0·92, CA = −0·91 ± 0·72, EA = −0·46 ± 0·79, Ad-SOS = −1·08 ± 1·11, BTT = −0·97 ± 1·07 and BBRI (342 ± 117 vs 649 ± 318 mm3) were all significantly lower than in controls (P < 0·05).

Conclusions

Obese children show an unfavourable bone geometry and a bone of low quality and reduced strength compared to controls at a nonweight bearing skeletal site. This finding seems to support a detrimental effect of fat mass on bone and explain the frequent occurrence of wrist fractures in this group of children.

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