ESA-SRB-AOTA 2019

Body weight and fat mass may negatively influence responses to high-dose vitamin D supplementation in overweight and obese older adults (#563)

Cecilia L H Xu 1 2 , Alexander J Rodriguez 1 , Mavil M Cervo 1 , Jakub Mesinovic 1 , Lachlan McMillan 1 , Catherine Shore-Lorenti 1 , Peter R Ebeling 1 , David Scott 1 3
  1. Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria, Australia
  2. Austin Health, Heidelberg , VIC, Australia
  3. Department of Medicine and Australian Institute for Musculoskeletal Science, The University of Melbourne, St Albans, Victoria, Australia

BACKGROUND: Overweight and obese older adults have increased risk of vitamin D deficiency. High-dose vitamin D3 supplementation is an effective treatment for vitamin D deficiency. However, high body fat mass and unfavourable body fat distribution may reduce responsiveness to supplementation.

AIM: To evaluate body weight and body composition as predictors of increases in serum 25-hydroxyvitamin D (25(OH)D) concentrations following 12 weeks of vitamin D3 supplementation in overweight and obese older adults with low 25(OH)D.

METHOD: Nineteen overweight and obese adults aged ≥50 years with baseline serum 25(OH)D concentrations <50 nmol/L were given 4000 IU/d of oral vitamin D3 for 12 weeks. Body weight, body mass index (BMI), waist circumference, waist-hip ratio, and body fat parameters estimated by dual-energy x-ray absorptiometry were measured at baseline and 12 weeks.

RESULTS: Mean±SD 25(OH)D was 41±10 nmol/L at baseline and 84±15 nmol/L at 12 weeks (p<0.05) with 100% of participants becoming vitamin D replete at 12 weeks. Serum 25(OH)D did not correlate with anthropometric or body composition measures at baseline. Body weight at baseline (r=-0.44, p=0.06) and android-to-gynoid fat ratio at baseline (r=-0.40, p=0.09) were both negatively correlated with changes in serum 25(OH)D.

CONCLUSIONS: Higher body weight and android relative to gynoid fat mass may predict a poorer response to vitamin D3 supplementation in overweight and obese older adults in line with theories around fat sequestration of vitamin D. Larger clinical trials are required to confirm these negative effects of body weight and fat mass on responses to vitamin D supplementation.