Prevalence of vitamin D inadequacy in patients attending a metabolic bone clinic in Medway.
BACKGROUND
It is well established that vitamin D levels are sub-optimal in the elderly and that adults with fragility fracture have low levels of serum vitamin D.


OBJECTIVE
To investigate the prevalence of vitamin D inadequacy in Medway, Kent in patients attending a metabolic bone clinic and in patients with fragility fractures and to compare levels with data previously presented from Glasgow.


METHODS
Retrospective patient records audit of patients attending the metabolic bone clinic from 1998 to 2005.


RESULTS
There were data for 870 patients, 77.5% of the patients were women (n = 674) and 48.2% (n = 420) of patients had a fragility fracture. The mean age was 61.6 years (SD = 14.12), 56.4% were aged 60 years or over and 17.7% were aged 75 years or over. The mean vitamin D level was 47.7 nmol/L (19.1 ng/mL), SD = 25.8 (10.3). Of the patients 88.7% had a vitamin D level < 80 nmol/L, 81.4% < 70 nmol/L and 59.1% < 50 nmol/L. Of the 420 patients with fragility fracture, 78.1% were women and the mean age was 66.6 years (SD = 12.22). The mean vitamin D level was 45.3 nmol/L (18.1 ng/mL), SD = 25.8 (10.3). In patients not receiving supplementation (n = 222) the mean vitamin D level was 40.5 nmol/L (16.2 ng/mL), SD = 20.9 (8.4) and 95.9% of patients had a vitamin D level < 80 nmol/L, 89.6% < 70 nmol/L and 71.2% < 50 nmol/L. In order to compare data from Medway with previously published data from Glasgow, a subset of 198 patients with fragility fracture, aged over 50 years, attending the metabolic bone clinic and not receiving supplementation with calcium and/or vitamin D was analysed. There were 76.6% women and the mean age was 68.6 years (SD = 9.1). The mean vitamin D level was 40.0 nmol/L (16.0 ng/mL), SD = 21.5 (8.6). Of these patients 96.4% had a vitamin D level < 80 nmol/L, 89.7% < 70 nmol/L and 73.2% < 50 nmol/L. Data on the month of vitamin D assessment were available for 499 patients. The mean vitamin D in the summer (April-September) months (n = 217) was significantly higher than in the winter (October-March) months (n = 281): 53.2 nmol/L (SD = 29.4) versus 47.3 (SD = 24.9), p = 0.02. Parathyroid hormone (PTH) levels were available for 289 patients. Mean vitamin D levels in the 47 patients with PTH levels above the reference range were significantly lower than vitamin D levels in the 238 patients within the reference range for PTH: mean 31.1 nmol/L, SD = 21.1 versus mean 46.5 nmol/L, SD = 24.8 (p = 0.000092). Four patients had PTH levels below the reference range.


CONCLUSIONS
The prevalence of vitamin D inadequacy is high in patients attending a metabolic bone clinic, in particular in those patients with fragility fractures. The prevalence of inadequacy is comparable with that seen in Glasgow.
Ryan
P
P
Osteoporosis Unit, Medway Maritime Hospital, Windmill Road, Gillingham, UK. paul.ryan@medway.nhs.uk
Dixon
T
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005598:Fractures, Spontaneous / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000453:epidemiology / Q000209:etiology; D010044:Outpatient Clinics, Hospital; D015995:Prevalence; D012621:Seasons; D006113:United Kingdom; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*
D014807:Vitamin D