Effect of Weight Loss, Exercise, or Both on Undercarboxylated Osteocalcin and Insulin Secretion in Frail, Obese Older Adults

Oxid Med Cell Longev. 2017:2017:4807046. doi: 10.1155/2017/4807046. Epub 2017 Aug 23.


Background: Obesity exacerbates age-related decline in glucometabolic control. Undercarboxylated osteocalcin (UcOC) regulates pancreatic insulin secretion. The long-term effect of lifestyle interventions on UcOC and insulin secretion has not been investigated.

Methods: One hundred seven frail, obese older adults were randomized into the control (N = 27), diet (N = 26), exercise (N = 26), and diet-exercise (N = 28) groups for 1 year. Main outcomes included changes in UcOC and disposition index (DI).

Results: UcOC increased in the diet group (36 ± 11.6%) but not in the other groups (P < 0.05 between groups). Although similar increases in DI occurred in the diet-exercise and diet groups at 6 months, DI increased more in the diet-exercise group (92.4 ± 11.4%) than in the diet group (61.9 ± 15.3%) at 12 months (P < 0.05). UcOC and body composition changes predicted DI variation in the diet group only (R2 = 0.712), while adipocytokines and physical function changes contributed to DI variation in both the diet (∆R2 = 0.140 and 0.107) and diet-exercise (∆R2 = 0.427 and 0.243) groups (P < 0.05 for all).

Conclusions: Diet, but not exercise or both, increases UcOC, whereas both diet and diet-exercise increase DI. UcOC accounts for DI variation only during active weight loss, while adipocytokines and physical function contribute to diet-exercise-induced DI variation, highlighting different mechanisms for lifestyle-induced improvements in insulin secretion. This trial was registered with ClinicalTrials.gov number NCT00146107.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Exercise / physiology*
  • Female
  • Frail Elderly
  • Humans
  • Insulin / metabolism*
  • Male
  • Obesity / therapy*
  • Osteocalcin / metabolism*
  • Weight Loss / physiology*


  • Insulin
  • Osteocalcin

Associated data

  • ClinicalTrials.gov/NCT00146107