ISRCTN11865958 ( http://www.isrctn.com ).

These results, which were recorded in a very homogeneous population of healthy postmenopausal women, indicate that there is a beneficial effect of animal and dairy protein intakes on bone strength and microstructure. Specifically, there is a positive association between the bone failure load and stiffness of the peripheral skeleton and dietary protein intake, which is mainly related to changes in the trabecular microstructure. This trial was registered at www.controlled-trials.com as ISRCTN11865958.

Fractures are common in otherwise healthy children and adolescents. They result from trauma of varying severity. Some reflect a greater skeletal fragility. A long-term implication of these fractures is their potentiality to predict adult bone fragility and increased risk of osteoporosis in later life. Using dual-energy X-ray absorptiometry (DXA), high-resolution peripheral quantitative computed tomography (HR-pQCT), and micro-finite element analysis (μFEA) measurements, we previously found in 124 healthy females, followed from the age of 7.9 to 20.4 years, substantial deficits in both structural and strength components of the radius in the 42 girls who sustained a fracture during skeletal development. The objective of the current study was to assess in healthy males the relationship between fracture during development and expression of bone fragility in adulthood. A cohort of 152 boys was followed from age 7.4 ± 04 (mean ± SD) to 22.6 ± 0.7 years, ie, when peak bone mass is attained. Ninety participants (59.2%) sustained at least one fracture during growth, with highest incidence within the 10- to 13-year age range. Forearm was the most frequent site of fractures. At 7.4 years, several bone DXA-measured variables (areal bone mineral density [aBMD], bone mineral content [BMC]) were lower in the group with a positive fracture history during skeletal development compared with the non-fractured group. In contrast, at 22.6 years, no DXA-measured sites, including forearm, indicated a deficit in the fractured group compared with the non-fractured group. Likewise, at 22.6 years, neither HR-pQCT nor μFEA measurements, including distal radius, showed a structural or strength deficit in the fractured group. These results markedly contrast with a similar prospective study using the same technical and clinical design in 124 healthy girls. In conclusion, our prospective studies suggest a sex difference in the predictability of bone fragility in young adults who sustained fractures during childhood and adolescence. This difference might be related to the degree of trauma severity, usually lower in girls than in boys. © 2017 American Society for Bone and Mineral Research.

Background The importance of dietary acid load (DAL) in the pathogenesis of osteoporosis is still debated. Age-related changes in bone microstructure and strength in relation to DAL remain largely unexplored. Objectives We investigated the associations between changes in areal and volumetric bone mineral density (BMD), bone microstructure and strength, fracture risk, and DAL in a prospective cohort of 65-y-old healthy men and postmenopausal women. Methods Potential renal acid load (PRAL; mEq/d) was calculated as a DAL proxy to characterize participants’ diet as alkaline (Alk-D; PRAL < −5), neutral (Neut-D; −5 ≤ PRAL ≤ 5), or acidic (Acid-D; PRAL >5). We measured areal BMD (aBMD) by DXA, and distal radius and tibia bone microstructure using high-resolution peripheral quantitative computed tomography, at baseline (n = 853) and after 6.1 ± 1.4 y (n = 708). Bone strength was estimated using finite element analyses at baseline and after 3.0 ± 0.5 y (n = 613). Prevalent and incident fractures were recorded. Results The majority of the participants (59%) had an Alk-D, while 23% had a Neut-D, and 18% an Acid-D. Baseline aBMD and bone microstructure and strength did differ or were slightly better in women or men with an Acid-D versus those consuming an Alk-D or Neut-D. Indeed, women with an Acid-D had higher trabecular number (P = 0.010 vs. Alk-D; P = 0.001 vs. Neut-D), while men had higher hip and radius aBMD (P = 0.008 and 0.024 vs. Neut-D, respectively) and radius strength (P = 0.026 vs. Neut-D). Over the follow-up, women in the Acid-D group experienced lower cortical and endocortical bone loss at the radius than did the Alk-D and Neut-D groups (cortical thickness, P = 0.008 and < 0.001; trabecular area, P = 0.001 and < 0.001, respectively). No association between fractures and PRAL was observed. Conclusions These null or favourable associations between baseline values or changes in aBMD, bone microstructure and strength, and DAL in this cohort of 65-y-old healthy individuals do not support adverse DAL-mediated effects on bone. This trial was registered at http://www.isrctn.com as ISRCTN11865958.

This study demonstrates the crucial influence of Prot-Int on the response to enhanced PA and the importance of prepubertal years for modifying the bone growth trajectory and, thereby, for achieving higher PBM and greater strength in healthy male participants.