(RxWiki News) Low vitamin D has been linked to a number of health problems, including bone disease. But new research suggests the health consequences of low vitamin D may be even more serious in some cases.
A recent review of research found that people with low levels of vitamin D in their blood were almost twice as likely to die early compared to people with high levels of vitamin D.
"Discuss your daily intake of vitamin D with your doctor."
The lead author of this review was Cedric Garland, DrPH, from the Department of Family and Preventive Medicine at the University of California, San Diego.
The review included 32 studies published between January 1, 1966 and January 15, 2013 on the relationship between vitamin D blood levels and death by any cause.
Each study reported on at least two different categories of blood vitamin D concentration.
The studies included a total of 566,583 participants from 14 different countries around the world.
The participants’ average age when they had their blood drawn was 55 years old, and the average follow-up time was nine years.
The specific type of vitamin D assessed was 25-hydroxyvitamin D — the most common form found in blood.
The highest category of blood vitamin D concentration consisted of concentrations above 50 nanograms per milliliter (ng/mL), and the lowest consisted of concentrations between 0 and 9 ng/mL.
The findings showed that the participants with concentrations in the lowest category were 90 percent more likely to die prematurely from any cause than those who had concentrations in the highest category.
Vitamin D concentrations of 30 ng/mL or less were also associated with an increased risk for premature death, accounting for about half of the deaths included in the review.
Dr. Garland noted that about two-thirds of the US population has blood vitamin D levels below 30 ng/mL.
"Three years ago, the Institute of Medicine (IOM) concluded that having a too-low blood level of vitamin D was hazardous," Dr. Garland said in a press statement. "This study supports that conclusion, but goes one step further. The 20 nanograms per milliliter (ng/ml) blood level cutoff assumed from the IOM report was based solely on the association of low vitamin D with risk of bone disease. This new finding is based on the association of low vitamin D with risk of premature death from all causes, not just bone diseases. "
The researchers believe that their findings should reassure the medical community and the general public that vitamin D is safe when used correctly. Co-author Heath Hofflich, DO, from the UC San Diego School of Medicine, considered up to 4,000 International Units (IU) per day to be an appropriate and safe dose.
However, the research team noted that patients should always talk to their doctor about appropriate doses of and whether or not changing daily intake is safe or not.
Lastly, Dr. Garland and team suggested that patients get their vitamin D blood levels tested each year.
This review was limited by the differences in designs of each study. Also, the studies were observational, so the review authors had no data on factors that may have affected the results.
This review was published on June 12 in the American Journal of Public Health.
The UC San Diego Department of Family and Preventive Medicine provided funding.