Oral Presentation ESA-SRB Conference 2015

Differential associations of ferritin and 25-hydroxyvitamin D with fasting glucose and diabetes risk in community dwelling older men. (#103)

Simon Carrivick 1 2 , Helman Alfonso 3 , Leon Flicker 1 4 , Jonathan Golledge 5 6 , Paula Clancy 5 , Jenny E. Gunton 7 , Graeme J. Hankey 1 , Osvaldo P. Almeida 4 8 , Paul E. Paul E. 9 , Bu B. Yeap 1 2
  1. School of Medicine and Pharmacology, University of Western Australia, Perth
  2. Department of Endocrinology and Diabetes, Fiona Stanley Hospital, Perth
  3. School of Public Health, Curtin University, Perth
  4. Western Australian Centre for Health and Ageing, Centre for Medical Research, University of Western Australia, Perth
  5. Vascular Biology Unit, Queensland Research Centre for Peripheral Vascular Disease, School of Medicine, James Cook University, Townsville
  6. Department of Vascular and Endovascular Surgery, Townsville Hospital, Townsville
  7. Westmead Hospital, University of Sydney, Sydney
  8. School of Psychiatry and Clinical Neurosciences, University of Western Australia, Perth
  9. School of Surgery, University of Western Australia, Perth

AimsHigh ferritin and low vitamin D concentrations are associated with an increased incidence and prevalence of diabetes mellitus but the strength and nature of the association in older adults remains unclear. We examined the roles of ferritin and 25-hydroxyvitamin D as independent predictors of glycaemia in older men.

MethodsCross-sectional analysis of a population-based cohort study of 4,248 community dwelling older men aged 70-89 years in Perth, Western Australia. Plasma ferritin, 25-hydroxyvitamin D and glucose were assayed. Diabetes was ascertained from self-report, medication usage and fasting glucose concentrations. Multivariate analyses adjusted for age, smoking, BMI, waist:hip ratio, physical activity, hypertension, lipids, creatinine, CRP and medical comorbidity.

ResultsThere were 588 men with diabetes (13.9%). Ferritin was associated with fasting glucose in non-diabetic men (0.05 mmol/L per 1SD increase in ferritin, p=0.01). 25-hydroxyvitamin D was inversely associated with fasting glucose in non-diabetic men (-0.08 mmol/L per 1SD, p<0.001). Ferritin was not associated with prevalent diabetes (highest vs. lowest quartile; >225 vs <65.5 ng/ml: adjusted odds ratio [OR] 0.91, 95% confidence interval [CI], 0.70-1.18, p=0.47). Higher vitamin D was associated with a decreased odds of prevalent diabetes (highest vs lowest quartile; >81.6nmol/L vs <52.9nmol/L: adjusted. OR=0.58, 95% CI=0.44-0.75, p<0.001). There was no interaction between ferritin and vitamin D on diabetes risk. The results were similar after exclusion of diabetic men using insulin.

ConclusionsIn older men, increased ferritin is associated with increased plasma fasting glucose concentrations; however it is not a predictor of overall diabetes risk. Higher 25-hydroxyvitamin D concentrations are independently associated with lower fasting glucose levels and reduced risk of diabetes. In older adults manipulation of plasma ferritin may not alter diabetes risk, whereas interventional studies are required to determine whether vitamin D supplementation reduce the incidence of diabetes as vitamin D levels are associated with other health indices.