The study, funded by Spanish company Faes Farma, compared weekly calcifediol (25-hydroxyvitamin D) supplementation with placebo over 12 months in 261 women. The researchers in Spain, some of whom were employed by Faes Farma, assessed vit D levels and whether BMI or menopausal status affected treatment outcomes.
“Weekly calcifediol 100 µg is a safe and effective option for achieving and maintaining adequate vitamin D levels in vitamin D-deficient women over a period of 12 months, and is associated with consistent effects across BMI and menopausal status,” they wrote.
Vitamin D, bone health and menopause
Vitamin D plays an important role in bone health and calcium absorption. The body produces around 80% of its vitamin D through sunlight exposure, while the remaining 20% comes from food. The liver converts vitamin D3 into calcifediol, the main form measured to assess vitamin D levels in the blood, and the kidneys then convert it into its active form.
During and after menopause, declining estrogen levels accelerate bone loss and increase the risk of osteoporosis and fractures. At the same time, aging can reduce the skin’s ability to produce vitamin D and affect the body’s ability to absorb calcium efficiently. For this reason, maintaining adequate vitamin D levels is particularly relevant after menopause, the researchers noted.
“Given the physiological and hormonal changes associated with menopause, as well as the recognized impact of adiposity on vitamin D metabolism and distribution, exploring the consistency of treatment response across these subgroups may provide clinically relevant information for women’s health,” the researchers wrote.
Weekly calcifediol rapidly raises vit D levels
The researchers analyzed data from a 52-week randomized, double-blind clinical trial involving 261 women with vitamin D deficiency. The women received either 100 µg of calcifediol once a week or a placebo.
They measured their vitamin D levels at regular intervals to assess how many reached at least 20 or 30 ng/mL. They also examined whether body weight or menopausal status affected treatment response and monitored side effects and safety throughout the study.
Results showed that weekly calcifediol significantly increased vitamin D levels compared with placebo. By week 4, 68.2% of women receiving calcifediol reached at least 20 ng/mL, compared with 5.8% in the placebo group. By week 16, more than 93% maintained this level, with benefits lasting throughout the 52-week study. Average vitamin D levels also rose from 12.21 ng/mL to 39.47 ng/mL by week 16 and remained above 41 ng/mL thereafter.
The treatment worked similarly across BMI groups and in premenopausal and postmenopausal women. At week 52, more than 93% of both menopausal groups achieved vitamin D levels of at least 20 ng/mL. The researchers noted that its predictable relationship between dose and blood vitamin D levels may explain why women across different BMI groups responded similarly.
“In this context, weekly calcifediol 100 µg may represent a practical dosing strategy across different life stages, particularly in routine gynecological practice, where a single weekly regimen could simplify treatment decisions across different ages and clinical contexts,” the researchers concluded.
They did however note that the study was exploratory and was not designed to compare treatment responses across BMI or menopausal groups, and that further research is needed to confirm whether the consistent response observed in women also applies across different subgroups and between men and women.
Source: Nutrients; doi: https://doi.org/10.3390/nu18213658; “Weekly Calcifediol 100 µg in Women with Vitamin D Deficiency: A Post Hoc Analysis of a Randomised Placebo-Controlled Phase II/III Trial.” Authors: Pérez Castrillón, J, L. et al.
