Oral Presentation Australian & New Zealand Obesity Society Annual Scientific Meeting 2013

Vitamin D deficiency is associated with hypertension and metabolic syndrome in overweight and obese youth (#82)

Kung-Ting Kao 1 , Nobia Abidi 2 , Sanjeeva Ranasinha 2 , Justin Brown 3 , Christine Rodda 4 , Zoe McCallum 5 , Margaret Zacharin 6 , Peter J Simm 7 , Matthew Sabin 8
  1. The Royal Children's Hospital and Murdoch Childrens Research Institute, Parkville, VIC, Australia
  2. Monash University, Clayton, VIC, Australia
  3. Monash Children's and Monash University, Clayton, VIC, Australia
  4. Monash Children's and University of Melbourne, Clayton and Parkville, VIC, Australia
  5. The Royal Children's Hospital and University of Melbourne, Parkville, VIC, Australia
  6. The Royal Children's Hospital, Murdoch Childrens Research Institute and University of Melbourne, Parkville, VIC, Australia
  7. The Royal Children's Hospital, Murdoch Childrens Research Institute and Monash Children's, Parkville and Clayton, VIC, Australia
  8. The Royal Children's Hospital, Murdoch Childrens Research Institute, University of Melbourne and Monash University, Parkville and Clayton, VIC, Australia

Vitamin D (25OHD) has significant metabolic effects but few studies have examined the correlation between 25OHD status and levels of adiposity/metabolic health in large cohorts of overweight/obese children.

We conducted a retrospective study of patients attending tertiary weight management services at The Royal Children’s Hospital Melbourne and Monash Children’s (Jan 2009-Nov 2011). 25OHD data were available in 229 patients (age 3-18 years; 116 male; mean [SD] BMI Z-score 2.5 [0.5]). Serum 25OHD levels were stratified into quintiles for the purpose of regression analysis. Chi-squared test was used for group comparisons. Logistic regression and multivariable analysis were used to derive the odds ratios for the prevalence of metabolic syndrome and the association between metabolic syndrome and 25OHD levels respectively.

104 (45%) subjects were 25OHD deficient (<50 nmol/L). 72 subjects met the NCEP-ATP III criteria for metabolic syndrome. The proportions of subjects in the lowest 25OHD quintiles were significantly higher in winter than summer (p = 0.05), and no differences were found for sex, age or pubertal stage.

A significant linear relationship was seen in the odd ratios between serum 25OHD quintiles and prevalence of metabolic syndrome, adjusted for season, age and sex (p = 0.04). Serum 25OHD levels were significantly lower in those with higher systolic (p = 0.03) and diastolic blood pressure (p = 0.009), higher BMI z-score (p = 0.001), increased levels of total fat mass (p = 0.009) and higher serum phosphate levels in a multivariable-adjusted regression analysis.

In summary, we report a high prevalence of 25OHD deficiency in overweight/obese youth. Furthermore, decreasing serum 25OHD levels appear associated with a higher prevalence of metabolic syndrome, degree of obesity, hypertension and total fat mass. It remains unclear, at the present time, whether vitamin D supplementation in obese children will be associated with improvements in adiposity and metabolic health.