Even Supplement Users Can Have Low Vitamin D Levels


WASHINGTON — A whopping 97% of 78 patients hospitalized for minimal trauma fractures had vitamin D levels of less than 30 ng/mL, Christine Simonelli, M.D., said at an international symposium sponsored by the National Osteoporosis Foundation.

Even the patients who took at least 400 IU of vitamin D had inadequate vitamin D levels, added Dr. Simonelli of HealthEast Medical Research Institute, St. Paul, Minn. More than 90% of 39 patients who took at least 400 IU of vitamin D still had serum vitamin D levels below 30 nanograms per mL.

But there was a significant difference overall in the mean serum vitamin D levels between patients who took at least 400 IU of vitamin D and those who took 400 IU of vitamin D supplementation or less (16.4 ng/mL vs. 11.9 ng/mL).

Patients who took at least 400 IU of vitamin D as a daily supplement were significantly less likely to have vitamin D levels in the lowest cutoff group—less than 9 ng/mL—than were patients who took less than 400 IU of vitamin D daily.

The mean vitamin D levels were not significantly different based on age, gender, or use of an osteoporosis medication.

The mean serum 25-hydroxyvitamin D [25(OH)D] level was 14.1 ng/mL among the 61 women in the study, and 14.3 ng/mL among the 17 men. All the patients were aged 50 years or older, all except one were white, and were hospitalized with a fracture between August 1, 2001 and January 31, 2002.

Almost all (97%) of the patients had hip fractures, and 10 (12%) of them were taking an osteoporosis medication prior to their hospital admissions. The investigators excluded patients with high-impact trauma fractures and metastatic cancer diagnoses.

A total of 14 patients (18%) were taking vitamin D only, while 36 (46%) reported taking a multivitamin only and 39 (50%) reported taking vitamin D and/or multivitamins. The study was limited by its small size, lack of ethnic minorities, and possible lack of generalizability to other populations, Dr. Simonelli and her colleagues wrote.

“Half of the patients had little or no vitamin D supplementation,” Dr. Simonelli noted.

Dr. Simonelli received research support from Merck & Co. for this study.

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