Changing Incidence of Serum 25-Hydroxyvitamin D Values Above 50 ng/mL: A 10-Year Population-Based Study.
OBJECTIVE
To determine the incidence trend of 25-hydroxyvitamin D (25(OH)D) values above 50 ng/mL and associated toxicity.


METHODS
We conducted a retrospective population-based study in Olmsted County, Minnesota, in the 10-year period from January 1, 2002, through December 31, 2011, by using the Rochester Epidemiology Project. Individuals were eligible if they resided in Olmsted County during the study period and had a measured 25(OH)D value above 50 ng/mL. The date of the first 25(OH)D value above 50 ng/mL was considered the index date for incidence determination. Hypercalcemia, the primary vitamin D toxicity, was considered potentially associated with the 25(OH)D concentration if it was measured within 3 months of the 25(OH)D measurement, and such cases had a medical record review.


RESULTS
Of 20,308 total 25(OH)D measurements, 1714 (8.4%), 123 (0.6%), and 37 (0.2%) unique persons had 25(OH)D values above 50, 80 and above, and 100 ng/mL and above, respectively. The age- and sex-adjusted incidence of 25(OH)D values above 50 ng/mL increased from 9 to 233 cases per 100,000 person-years from 2002 to 2011 (P<.001), respectively, and was greatest in persons aged 65 years and older (P<.001) and in women (P<.001). Serum 25(OH)D values were not significantly related to serum calcium values (P=.20) or with the risk of hypercalcemia (P=.24). A medical record review identified 4 cases (0.2%) in whom 25(OH)D values above 50 ng/mL were temporally associated with hypercalcemia, but only 1 case had clinical toxicity associated with the highest observed 25(OH)D value of 364 ng/mL.


CONCLUSIONS
The incidence of 25(OH)D values above 50 ng/mL increased significantly between 2002 and 2011 without a corresponding increase in acute clinical toxicity.
Department of Internal Medicine, Mayo Clinic, Rochester, MN. Electronic address: dudenkov.daniel@mayo.edu.
Daniel V
DV
Dudenkov
Olmsted Medical Center, Rochester, MN.
Barbara P
BP
Yawn
Department of Family Medicine, Mayo Clinic, Rochester, MN.
Sara S
SS
Oberhelman
Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN.
Philip R
PR
Fischer
Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN.
Ravinder J
RJ
Singh
Department of Health Science Research, Mayo Clinic, Rochester, MN.
Stephen S
SS
Cha
Department of Family Medicine, Mayo Clinic, Rochester, MN.
Julie A
JA
Maxson
Department of Family Medicine, Mayo Clinic, Rochester, MN.
Stephanie M
SM
Quigg
Department of Family Medicine, Mayo Clinic, Rochester, MN.
Tom D
TD
Thacher
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000453:epidemiology*; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
D014807:Vitamin D; C104450:25-hydroxyvitamin D