Prevalence and metabolic abnormalities of vitamin D-inadequate patients presenting with urolithiasis to a tertiary stone clinic.
OBJECTIVE
To assess the prevalence and metabolic abnormalities of patients with inadequate vitamin D (VD) presenting with urolithiasis to a tertiary stone clinic in North America.


METHODS
A retrospective review of consecutive patients presenting from August 2009 to January 2010 was performed. Demographic and clinical data were collected together with metabolic stone workup, including 2 24-hour urine collections and serum 25-hydroxy VD [25(OH)D]. VD inadequacy (VDI) included VD deficiency and VD insufficiency defined as 25-(OH) VD levels <20 ng/mL and 21-29 ng/mL, respectively.


RESULTS
Of 101 patients, 81 (80.2%) were found to have VDI: 34 (33.7%) were deficient and 47 (46.5%) had insufficient VD. Mean age was 50.4 ± 15.8 years and the mean body mass index was 28.7 ± 5.8 kg/m(2). Forty-two percent were smokers, 51% were recurrent stone formers, and 54% had positive family history of urolithiasis. Hyperparathyroidism was detected in 25.9% of patients, of which 91% of them were secondary to VDI. Hypocalcemia and hyperuricemia were found in 36% and 11% of patients, respectively. Of 81 VDI patients, 69 (85.2%) had complete 24-hour urine collections, of which 92.7% had at least one abnormality. However, only 40% of patients with normal VD had metabolic abnormalities (P <.0001). The most prevalent pattern of urinary abnormalities in VDI patients were suboptimal volume (45%), hypocitaturia (24%), hypocalciuria (33%), hypercalciuria (20%), hyperuricosuria (16%), cystinuria (5%), and hyperoxaluria (7.2%).


CONCLUSIONS
In this preliminary study, patients presenting with urolithiasis were found to have a high prevalence of inadequate VD associated with abnormalities on metabolic stone work-up.
Division of Urology, McGill University Health Centre, McGill University, Montreal, Quebec, Canada.
Mohamed A
MA
Elkoushy
Ramsey
R
Sabbagh
Bernard
B
Unikowsky
Sero
S
Andonian
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D006801:Humans; D053565:Hypercalciuria / Q000453:epidemiology; D006959:Hyperoxaluria / Q000453:epidemiology; D006961:Hyperparathyroidism / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011792:Quebec / Q000453:epidemiology; D012189:Retrospective Studies; D052878:Urolithiasis / Q000453:epidemiology*; D014808:Vitamin D Deficiency / Q000453:epidemiology* / Q000378:metabolism*; D055815:Young Adult