Vitamin D in postmenopausal women, older women, and women at risk for bone diseases

Posted September 3rd, 2020

Vitamin D is considered a worldwide public health problem, but its supplementation, specifically in postmenopausal women, older women, and women at risk for bone diseases, requires more attention, since it is an essential hormone for the maintenance of calcium levels and bone health.

Published in March of this year, the Consensus Statement from the 2nd International Conference on Controversies in Vitamin D is the result of a meeting with a group of researchers from all over the world that aimed to address controversies on the subject, promote discussions, and suggest a research agenda to clarify any points of uncertainty. The coordinator of INCT Hormona at Universidade Federal de São Paulo (UNIFESP), Dr. Marise Lazaretti Castro, attended this meeting and is one of the co-authors of the statement.

Pregnancy and lactation

The use of vitamin D during pregnancy and lactation was one of the topics addressed in the Conference. According to the Consensus, growing evidence shows that vitamin D is a necessary essential nutrient for conception, normal function of placenta, and maternal and fetal immune homeostasis. It is also considered a key factor for continuous well-being during lactation.

Data from results of four randomized clinical trials, in addition to other studies presented in the Conference, support Barker’s hypothesis, which sees vitamin D as a paramount factor in motherhood and child well-being. The text concludes that skin color is also an important factor in vitamin D homeostasis, since the women most affected by lower vitamin D levels were those with darker skin or with limited sun exposure.

For this reason, ensuring adequate vitamin D intake during pregnancy and lactation should be an integrant part of global public health policies.

Older women and neurologic deficits

According to the Consensus, evidence shows that the vitamin D hormone may be an important role in aging and age-related cognitive decline. Therefore, several neurological disorders have been possibly related to vitamin D deficiency, including multiple sclerosis, Parkinson disease, and Alzheimer disease.

Despite this association, there is still no consensus on the potential causative factor of the above diseases; thus, a research agenda was created to better understand the role of vitamin D in neurologic diseases.

Use in the post-menopausal period and in older women

Vitamin D is associated with prevention of a number of complications from chronic diseases, such as risk of fractures and falls. According to the Consensus, a recent meta-analysis of 29 randomized placebo-controlled, randomized, intervention trials revealed that vitamin D supplementation improved muscle strength. It also showed positive effects in improving balance in older adults.

However, evidence shows varied results far. A 2011 meta-analysis concluded that a dose of 700 to 800 IU was necessary to reduce risk of falls and that the ideal dose led to a 15% decrease in such risk.

Another study with post-menopausal women showed that neither a 800 IU daily dose nor a 50,000 IU dose twice a month had an influence on the risk of falls. A similar negative result was observed in another test with 800 IU in more than 400 women aged from 70 to 80 years old.

However, an intervention study assessing several doses of vitamin D supplementation – ranging from 400 to 4,800 IU daily – found a significantly lower number of falls among post-menopausal women taking daily doses of 1.600-3.200 UI.

The Consensus concluded that de vitamin D deficiency is associated with muscle dysfunction and falls in older adults, and that vitamin D supplementation, in turn, showed controversial results, either reducing or increasing the risk of falls in individuals with moderate vitamin D deficiency.

Still according to the researchers, the ability of “seeing” or “not seeing” an effect on the risk of falls, and maybe other results of vitamin D actions, may depend on whether the study population is vitamin D deficient or not. Since it is a threshold nutrient, beneficial results would not be expected unless the study population is vitamin D deficient.