Purpose: The aim of our study was to evaluate bone quality by quantitative ultrasound (QUS) at the phalanges in 129 monozygotic twin couples, outlining the differences between growing subjects and adults.
Materials and methods: A total of 129 healthy monozygotic twin couples (42 of children under 18 years of age and 87 of adults) were studied by phalangeal QUS, measuring amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT). Anthropometric data were also recorded.
Results: In children AD-SoS and BTT were positively correlated with age (r = 0.91, r = 0.91), height (r = 0.88, r = 0.90) and weight (r = 0.81, r = 0.87); in adults AD-SoS was negatively related to age (r = -0.36), AD-SoS and BTT were positively related to height (r = 0.37, r = 0.58). Absolute value differences between twins for AD-SoS and BTT were significantly higher in adult twins (25.9 ± 21.9 for AD-SoS and 0.08 ± 0.08 for BTT) than in children (14.5 ± 12.4 for AD-SoS and 0.05 ± 0.04 for BTT).
Conclusion: Differentiation in bone tissue quality in twins increases with age, probably reflecting lifestyle, personal habits, likely acting through epigenetic mechanisms.