A study by Loyola University in Chicago suggests that as many as 80 million Americans may be unnecessarily taking vitamin D supplements. The study is one of many to support new vitamin D supplement recommendations by the Institute of Medicine, which changed the definition of a person with vitamin D deficiency from having blood levels lower than 30 nanograms per millileter (ng/mL) to 20 or less.
The researchers looked at data for more than 15,000 healthy adults from the third National Health and Nutrition Examination Survey. They compared that to 18 years of National Death Index data to see whether vitamin D levels affected the rate of death. Seventy percent had vitamin D levels deficient under the old guidelines, but only 30 percent under the new guidelines. The death rate was highest among those with vitamin D levels below 12 ng/mL compared with any other levels. The death rate was the same at levels between 20 and 40 ng/mL, supporting the lower deficiency threshold.
BOTTOM LINE: A new study supports revised guidelines stating vitamin D supplements may be beneficial only when blood levels are lower than 20 ng/mL.
CAUTIONS: This observational study did not compare deaths among those who took vitamin D supplements and those who did not.
WHERE TO FIND IT: PLoS ONE, Oct. 24
Early start of hormone therapy may reduce Alzheimer’s risk
Women who begin hormone replacement therapy within the first five years of menopause may be at lower risk of developing Alzheimer’s disease than women who don’t take hormones, but those who begin therapy after age 65 may be at higher risk, according to a new study.
The findings come on the heels of reaffirmed recommendations by the US Preventive Services Task Force against the use of hormone therapy to prevent chronic diseases. Studies have suggested that long-term use of hormones among post-menopausal women can increase the risk of heart disease and certain cancers.
Researchers at Johns Hopkins University followed more than 1,700 women ages 65 and older for 11 years, more than 1,100 of whom had used either estrogen alone or a combination of estrogen and progestin. Among all the women, 176 developed Alzheimer’s disease, about half of whom were on hormone therapy.
The women who began hormone therapy within five years of menopause had a 30 percent lower risk of developing Alzheimer’s disease compared with those did not use hormones. The risk of Alzheimer’s significantly increased among women who began combined hormone therapy at age 65 or older.
BOTTOM LINE: Women who take hormone therapy within the first five years of menopause may be at lower risk of developing Alzheimer’s disease than women who don’t take hormones.
CAUTIONS: The findings of this observational study have not been confirmed by additional research.
WHERE TO FIND IT: Neurology, Oct. 24