title: Association between vitamin D and pressure ulcers in older ambulatory adults: results of a matched case-control study.
abstract: BACKGROUND
  Pressure ulcers are common among older adults, but knowledge about nutritional risk factors is still developing. Vitamin D deficiency is common in the elderly population and is required for normal skin proliferation. The role of vitamin D in pressure ulceration and wound healing is not known. The purpose of this case-control study was to determine the association between vitamin D levels and pressure ulceration in an older community-dwelling cohort.
  
  
  METHODS
  All cases and controls were community-dwelling elderly older than 60 years in a primary care panel in Olmsted County, MN. Pressure ulcer cases were defined clinically. The controls were age-matched and gender-matched to controls without pressure ulceration. The main exposure variable was 25-hydroxyvitamin D levels in both groups. The other exposure variable was the Charlson Comorbidity Index used to measure medical comorbidity. The analysis included univariate and conditional logistic regression for 25-hydroxyvitamin D levels.
  
  
  RESULTS
  The average (standard deviation) age of the study participants with a pressure ulcer was 80.46 years (±8.67), and the average vitamin D level was 30.92 ng/mL (±12.46). In univariate analysis, Vitamin D deficiency (levels < 25 ng/mL) was associated with pressure ulcers (odds ratio: 1.871, P = 0.0154). Comorbidities of the subjects calculated using the Charlson Comorbidity Index were also associated with pressure ulcers (odds ratio: 1.136, P < 0.001). In the final conditional logistical regression model, the association of Vitamin D and pressure ulcers became nonsignificant after adjustment for comorbid illness.
  
  
  CONCLUSIONS
  Medical comorbidities increased the risk of pressure ulceration. Vitamin D deficiency was not an independent risk factor for pressure ulceration, and may be a marker of comorbid illness.
authors.affiliation: Department of Internal Medicine, Division of Primary Care Internal Medicine, Mayo Clinic, Rochester, MN, USA.
authors.forename: Usha R
authors.initials: UR
authors.lastname: Kalava
authors.forename: Stephen S
authors.initials: SS
authors.lastname: Cha
authors.forename: Paul Y
authors.initials: PY
authors.lastname: Takahashi
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D010865:Pilot Projects; D003668:Pressure Ulcer / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D014945:Wound Healing / Q000502:physiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D