Effect of protein supplementation on hip bone mineral density, cortical thickness, and bone strength in older adult participants during a caloric restriction and aerobic exercise weight loss intervention: a randomized controlled trial.

Hip bone strength increased significantly more in the 18-month higher protein group compared to the recommended protein group at 6 months despite similar weight loss across groups.

• Hip bone strength increased 3.8 ± 1.7% over 6 months in the 18-mo HiProt group vs. 0.5 ± 1.6% in the RecProt group (p = 0.02)
• Six-month weight loss was similar across groups (-8.0 ± 5.0%)
• No significant differences were found between the 6-month higher protein group (6-mo HiProt) and the other groups
• Bone strength was assessed via finite element modeling of a sideways fall

Greater weight loss was associated with greater gains in hip bone strength at 6 months but greater bone density loss at 18 months.

• Greater weight loss was associated with greater gains in hip bone strength at 6 months (p = 0.007)
• Greater weight loss was associated with greater trabecular vBMD loss at 18 months (p = 0.011)
• Greater weight loss was associated with greater aBMD loss at both 6 and 18 months (p < 0.001)
• Associations were assessed using Spearman's correlations of weight loss vs. bone changes

Eighteen-month group differences in hip bone outcomes were non-significant across all three protein intake groups.

• No significant between-group differences were observed at 18 months for any hip bone outcome
• Three groups were compared: RecProt (0.8 g protein/kg/day), 6-mo HiProt (1.2 g/kg/day for 6 months), and 18-mo HiProt (1.2 g/kg/day for 18 months)
• The 12-month maintenance phase followed the 6-month active weight loss period
• Analyses were conducted using analysis of covariance

The trial enrolled 187 older adults with overweight/obesity who underwent 6 months of caloric restriction plus aerobic exercise followed by a 12-month maintenance phase.

• Sample size was 187 older adult participants
• Participants had overweight or obesity
• The intervention consisted of caloric restriction combined with aerobic exercise for 6 months of active weight loss
• Participants were randomized to one of three protein intake groups: RecProt, 6-mo HiProt, or 18-mo HiProt
• CT scans were obtained at baseline, 6 months, and 18 months and analyzed for hip volumetric BMD, cortical thickness, and bone strength

Hip bone mineral density and cortical thickness were assessed using CT-derived volumetric measures and dual-energy X-ray absorptiometry.

• CT scans were analyzed for hip volumetric bone mineral density (vBMD) and cortical thickness
• Areal BMD was measured with hip dual-energy X-ray absorptiometry (DXA)
• Bone strength was assessed via finite element modeling of a sideways fall
• Scans were performed at three time points: baseline, 6 months, and 18 months