Seven years after concluding that the evidence was insufficient to recommend the detection of vitamin D deficiency in the general population, the United States Preventive Services Working Group (USPSTF) has reviewed the issue and reached the same conclusion.
Overall, “the current evidence is inadequate in determining whether screening and treatment of low asymptomatic levels of 25 (OH) D improve clinical outcomes in adults living in the community,” the working group concludes in its statement. , which recommends an “I” for insufficient.
The statement was published online on April 13 a JAMA.
In the absence of screening recommendations, it is best for clinicians to focus on diet and supplementation for those considered at risk, said Anne R. Cappola, MD, of the Perelman School of Medicine at the University of Pennsylvania. Philadelphia.
“Instead of raising the issue of detecting vitamin D deficiency in the general population, we focus on making sure everyone consumes the recommended daily amount based on vitamin D age,” Cappola said. co-author of the accompanying editorial. Medscape Medical News.
No studies have directly evaluated the benefits of screening
The latest USPSTF recommendation is based on a systematic review of the benefits and harms of screening and early treatment of vitamin D deficiency in asymptomatic nonpregnant adults 18 years of age or older in the field of primary care without signs. nor symptoms of deficiency.
The review did not find studies that directly evaluated the benefits of detecting vitamin D deficiency.
However, 26 randomized clinical trials and a study of nested cases and controls evaluated the efficacy of treating vitamin D deficiency with supplements.
And, although observational studies have linked lower levels of vitamin D to a multitude of conditions and risks, the evidence for any benefit was inconsistent, with no one identified for most important outcomes in asymptomatic adults. focus of the working group recommendation.
“Among asymptomatic community populations with low vitamin D levels, evidence suggests that vitamin D treatment has no effect on mortality or the incidence of fractures, falls, depression, diabetes, cardiovascular disease, cancer, or adverse events.” , review the authors of stress.
“Evidence is inconclusive about the effect of treatment on physical functioning and infection.”
1 in 4 are Vitamin D deficiency
In terms of the additional question about the possible damage of vitamin D screening of asymptomatic individuals, a key concern is the potential for misclassification and excessive or insufficient diagnosis due to inconsistent cuts and the variability of different screening trials, concludes the review.
However, with the rare exception of vitamin D toxicity for supplements well above sufficient levels, treatment with vitamin D supplements seems relatively safe.
With a lack of consensus, even on the basic limit of vitamin D deficiency, the National Academy of Medicine determined in 2011 that hydroxyvitamin D (25[OH]D) levels below 20 ng / ml are deficient for bone health, with no evidence of different thresholds for any other health condition.
Under this limit, the National Health and Nutrition Examination Survey (NHANES) reported in 2014 that 25% of the U.S. population over the age of 1 had vitamin D deficiency, and 18% of the population had 25 (OH) D levels of 12 to 19 ng / ml and 5% with very low levels (<12 ng / ml).
More work is needed to determine the groups at risk
Although the report of the working group did not delve into the recommendations for testing or treatment for symptomatic adults, the main established risk factors that can help doctors identify those who are deficient in vitamin D are obesity, little or no exposure to UVB light and older age.
In general, obesity is associated with a 1.3 to 2 times risk of being deficient in vitamin D according to the criteria used, while non-Hispanic blacks are 2 to 10 times more likely to be deficient compared to non-Hispanic white patients. Working group notes.
However, the implications of vitamin D deficiency in certain populations may vary. For example, non-Hispanic blacks, despite having a higher prevalence of lower vitamin D levels than whites, do in fact have lower fracture rates.
To address the various issues and gain a better understanding of the complexities of vitamin D deficiency, the working group calls for additional research into key areas.
“More research is needed to determine whether total serum levels of 25 (OH) D are the best measure of vitamin D deficiency and whether the best measure of vitamin D deficiency varies by subgroups defined by race, ethnicity, or sex. “, they indicate.
In addition, “further research is needed to determine the limit that defines vitamin D deficiency and whether this limit varies according to specific clinical outcome or by subgroups defined by race, ethnicity, or sex.”
There is no support for population-based detection in the guidelines
With the lack of conclusive evidence, no organization currently recommends population-based screening for vitamin D deficiency in asymptomatic patients, and the American Society of Clinical Pathology supports this position.
Meanwhile, the Endocrine Society and the American Association of Clinical Endocrinologists (AACE) recommend the detection of vitamin D deficiency in patients considered at risk.
The data show that there was an 80-fold increase in Medicare reimbursement volumes for vitamin D testing among physicians from 2000 to 2010; however, that rate may have declined after the National Academy of Medicine reported established levels of deficiency, said Sherri-Ann M. Burnett-Bowie, MD, MPH, co-author of Cappola’s editorial.
Burnett-Bowie noted that he regularly tests his patients ’vitamin D levels, but most of his patients have osteoporosis or fractures.
“I examine them for vitamin D deficiency, as optimizing their vitamin D will improve calcium absorption, which is important in treating their osteoporosis,” said Burnett-Bowie of the Endocrine Division, Department of Medicine, Massachusetts General Hospital Boston. Medscape Medical News.
In terms of broader trials of asymptomatic patients in the general population, however, any change in screening will likely depend on the evolution of the effects of treatment, he said.
“Given the challenge of finding benefits from vitamin D supplementation in those who are deficient, it will probably be more difficult to find benefits from broader screening,” he concluded.
The USPSTF and the editorialists they have not reported any relevant financial relationships.
JAMA. Published April 13, 2021. Statement, revision, editorial
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