This article is more than 5 years old. Information may no longer be current.
Partial predictors discovered for vitamin D response variation in white postmenopausal women
Click Here to Manage Email Alerts
An increase in vitamin D supplementation, baseline serum 25-hydroxyvitamin D levels, and the season in which vitamin D supplementation is started may predict vitamin D response variations in white postmenopausal women, according to data from a 4-year study.
“To the best of our knowledge, this is the first study reporting that the season when vitamin D supplementation starts is an important factor in predicting vitamin D response variation,” the researchers wrote.
Lan-Juan Zhao, PhD, assistant professor of biostatistics and bioinformatics at Tulane University School of Public Health and Tropical Medicine in New Orleans, and colleagues enrolled 1,179 white postmenopausal women into a 4-year calcium and vitamin D (1,100 IU daily) clinical trial.
Of the 1,179 patients, 1,063 underwent 25(OH)D level measurement at baseline and after 12 months of treatment, and vitamin D response was calculated for the 1,063 patients as the difference in levels of serum 25-(OH)D at the end of the 12-month vitamin D treatment.
“This large vitamin D clinical trial identified that an increase in vitamin D, baseline serum 25-(OH)D level, and baseline blood collection season were the major predictors of vitamin D response variation,” the researchers said. “The baseline blood collection season was the season that an individual started her vitamin D clinical trial.”
Data confirmed that serum 25-(OH)D levels were lower in winter than in summer due to the synthesis of vitamin D resulting from the amount of sun exposure and time of year (P<.001).
Five factors — increase in vitamin D intake, baseline serum 25-(OH)D level, baseline blood collection season, baseline serum calcium level and baseline BMI — explained 46.8% of the vitamin D response variation in 1,063 patients, they said. Additionally, the first three factors were predictors in 392 patients with trial vitamin D supplementation.
For more information:
Zhao LJ. J Clin Endocrinol Metab. 2012;doi:10.1210/jc.2011-3401.
Disclosure: The researchers report no relevant financial disclosures.