Prevalence of vitamin D insufficiency in elderly ambulatory outpatients in Denver, Colorado

Am J Geriatr Pharmacother. 2007 Mar;5(1):1-8. doi: 10.1016/j.amjopharm.2007.03.005.

Abstract

Background: Vitamin D insufficiency is common in the elderly. However, previous studies have utilized 25-hydroxvvitamin D (25[OH]D) concentrations as low as <16 ng/mL for defining vitamin D insufficiency. Moreover, most of the studies have been conducted in European patients, in certain geographic areas of the United States, or in institutionalized elderly.

Objective: The goal of this study was to characterize vitamin D concentrations in ambulatory elderly living in metropolitan Denver, Colorado, utilizing 25(OH)D concentrations <32 ng/mL as the definition for vitamin D insufficiency.

Methods: Ambulatory older adults (aged 65-89 years) with clinic visits during December 2005 and January 2006 were enrolled. Serum concentrations of 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, creatinine, and albumin were measured; height and weight were also measured. Data regarding dietary and over-the-counter vitamin D intake were collected, as well as information on body mass index, history of osteoporosis, osteoporosis treatment, and history of falls and fractures.

Results: Eighty patients (mean [SD] age, 77.8 [5.3] years; age range, 66-89 years) completed the study; there were no dropouts. The majority of patients were white (88%) and female (68%). Fifty-nine (74%) were found to have vitamin D insufficiency. Mean total and over-the-counter vitamin D intake was significantly higher in sufficient (P < 0.01) and insufficient (P < 0.05) patients compared with deficient patients, but dietary intake did not differ significantly between groups. The majority of patients who were vitamin D insufficient consumed more than the recommended 400 to 600 IU/d of vitamin D. Obese patients were found to have significantly lower 25(OH)D concentrations (P < 0.001) and higher PTH concentrations (P = 0.04) than nonobese patients.

Conclusions: Vitamin D insufficiency is prevalent in ambulatory, and especially obese, elderly living in Denver, Colorado, despite vitamin D intake consistent with national recommendations. Dietary intake of vitamin D appeared to be unreliable to prevent insufficiency. Based on our results, along with other published data, we feel that national recommendations for vitamin D intake in the elderly should be increased to at least 800 to 1000 IU/d of over-the-counter supplemental cholecalciferol.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Aged
  • Aged, 80 and over
  • Ambulatory Care
  • Calcium / blood
  • Colorado / epidemiology
  • Creatinine / blood
  • Cross-Sectional Studies
  • Diet*
  • Female
  • Humans
  • Male
  • Nonprescription Drugs
  • Nutrition Policy
  • Obesity / complications
  • Outpatients
  • Parathyroid Hormone / blood
  • Phosphorus / blood
  • Prevalence
  • Prospective Studies
  • Risk Factors
  • Serum Albumin
  • Vitamin D / administration & dosage
  • Vitamin D / analogs & derivatives*
  • Vitamin D / blood
  • Vitamin D / therapeutic use*
  • Vitamin D Deficiency / epidemiology*
  • Vitamins / administration & dosage
  • Vitamins / therapeutic use*

Substances

  • Nonprescription Drugs
  • Parathyroid Hormone
  • Serum Albumin
  • Vitamins
  • Vitamin D
  • Phosphorus
  • 25-hydroxyvitamin D
  • Creatinine
  • Calcium