More Evidence That Vitamin-D Deficiency Ups Mortality CME/CE

[Neon Beach]

More Evidence That Vitamin-D Deficiency Ups Mortality CME/CE

News Author: Lisa Nainggolan
CME Author: Désirée Lie, MD, MSEd
Disclosures
Release Date: August 13, 2008; Valid for credit through August 13, 2009 Credits Available
Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™ for physicians;
Family Physicians - up to 0.25 AAFP Prescribed credit(s) for physicians;
Nurses - 0.25 nursing contact hours (None of these credits is in the area of pharmacology)
To participate in this internet activity: (1) review the target audience, learning objectives, and author disclosures; (2) study the education content; (3) take the post-test and/or complete the evaluation; (4) view/print certificate View details.

Learning Objectives

Upon completion of this activity, participants will be able to:

1. Identify risk factors for 25-hydroxyvitamin D deficiency.
2. Describe the association between low 25-hydroxyvitamin D levels and all-cause mortality.

Authors and Disclosures

Lisa Nainggolan
Disclosure: Lisa Nainggolan has disclosed no relevant financial relationships.

Désirée Lie, MD, MSEd
Disclosure: Désirée Lie, MD, MSEd, has disclosed no relevant financial relationships.

Laurie Scudder, MS, NP-C
Disclosure: Laurie Scudder, MS, NP-C, has disclosed that she has owns stock, stock options, or bonds in Johnson & Johnson and Procter & Gamble.

Brande Nicole Martin
Disclosure: Brande Nicole Martin has disclosed no relevant financial information.




From Heartwire — a professional news service of WebMD
August 13, 2008 — Another study has found that that low levels of low 25-hydroxyvitamin D levels (25[OH]D) seem to be linked to an increased risk of death, this time in a nationally representative cohort [1]. Dr Michal L Melamed (Albert Einstein College of Medicine, Bronx, NY) and colleagues report their findings in the August 11/25, 2008 issue of the Archives of Internal Medicine.
Melamed told heartwire: "This is one of the largest studies, in 13,000 people, followed for an average of eight years, and is the first study to explore the association between vitamin-D levels and mortality in the overall population. This makes our results more generalizable."
Melamed and colleagues found those in the lowest quartile of vitamin-D levels had a 26% higher risk of all-cause mortality and a similar increased risk of cardiovascular disease (CVD) mortality, although the latter was not statistically significant. They did not find an association between low vitamin-D levels and cancer mortality or other causes of death, however.
She believes the time has now come for a randomized controlled trial with vitamin D looking specifically at cardiovascular events or mortality as an end point.
Vitamin D acting before CVD is established?
In their study, Melamed et al tested the association of low 25(OH)D levels with all-cause, cancer, and CVD mortality in 13,331 adults aged 20 or older from the Third National Health and Nutrition Examination Survey (NHANES III). Vitamin-D levels were collected from participants between 1988 and 1994, and individuals were passively followed for mortality through 2000.
Increasing age, female gender, nonwhite race/ethnicity, diabetes, current smoking, and higher body-mass index (BMI) were all independently associated with higher odds of vitamin-D deficiency (lowest quartile of 25[OH]D levels < 17.8 ng/mL).
During 8.7 years of follow-up, there were 1806 deaths, including 777 from CVD. After multivariate adjustment, being in the lowest quartile compared with the highest quartile of vitamin D (> 32.1 ng/mL) was associated with a mortality rate ratio of 1.26 (95% CI 1.08 - 1.46) and a population-attributable risk of 3.1%.
The mortality rate ratio for CVD mortality in the lowest vs the highest quartile was 1.20 (95% CI 0.87 - 1.64) and for cancer mortality 0.91 (95% CI 0.62 - 1.31).
Melamed explained that when they analyzed subgroups, they found that the risk for mortality in those in the lowest quartile of vitamin D was more evident in those who did not have CVD at the beginning of the study compared with those who did have CVD.
"This suggests to us that maybe, if vitamin D is playing a role in CVD, it is acting before the disease is established," she said, adding that this whole issue will require further study.
Go out in the sun, eat oily fish
Also, like other studies, they found that very high vitamin-D levels may be detrimental in some subgroups — in this particular study it was in women. "This suggests that, like anything in the body, there is an 'optimum' level of vitamin D," Melamed noted.
With regard to what doctors should do currently in terms of assessing vitamin-D levels, she said, "They should definitely be checked in people at risk of osteoporosis and perhaps in the other subgroups who are at risk of vitamin-D deficiency, such as women, those with high BMI, and ethnic minorities."
She said she would not advise people to take supplements without knowing their vitamin-D levels and that the most sensible advice for those wanting to ensure their levels remain optimal is to spend 10 to 15 minutes per day in the sun and to eat vitamin-D-fortified foods, such as milk and oily fish.
Dr. Melamed and this analysis and coauthor Dr. Erin D. Michos were supported by the National Institutes of Health. Dr. Michos is also supported by the PJ Schafer Cardiovascular Research Fund and has received consulting fees from Abbott Pharmaceuticals. Another study author is supported, in part, by the Paul Beeson Physician Faculty Scholars in Aging Program.

Source

1. Melamed ML, Michos ED, Post W, et al. 25-hydroxyvitamin D levels and the risk of mortality in the general population. Arch Intern Med. 2008;168:1629-1637.

The complete contents of Heartwire, a professional news service of WebMD, can be found at www.theheart.org, a Web site for cardiovascular healthcare professionals.
Clinical Context

25(OH)D deficiency is an unrecognized contributor to CVD, cancer, and overall mortality. Therapy with calcitriol may reduce these risks in those with end-stage renal failure, and with an optimal level of 25(OH)D of 30 ng/mL or higher, 41% of men and 53% of women in the United States would be deficient with levels below 28 ng/mL. Low levels of 25(OH)D are also associated with hypertension, diabetes, insulin resistance, and elevated BMI, which are all risk factors for CVD and all-cause mortality.
This is an observational longitudinal study within the Third National Health and Nutrition Examination Survey to examine the association between low 25(OH)D levels in noninstitutionalized civilian US adults and all-cause mortality.
Study Highlights

• Included were 13,331 participants representing 175 million people in the United States, with an overrepresentation of non-Hispanic blacks, Mexican Americans, and the elderly from US survey sites that included northern states surveyed in the summer and southern states surveyed in the winter to control for season.
• Participants were interviewed and received physical examination and laboratory testing at baseline between 1988 and 1994.
• Laboratory measures included 25(OH)D level after 12 hours of fasting with use of radioimmunoassay.
• Demographic, medical history, risk factors, and lifestyle factors including physical activity level were elicited.
• Mortality outcomes were collected during 9 years of follow-up with use of the National Death Index; death certificates were reviewed annually, with cause of death ascertained by the International Classification of Diseases, Ninth Revision, Clinical Modification, and the International Classification of Diseases, 10th Revision, codes.
• Multivariate logistic regression was used to determine independent predictors of 25(OH)D deficiency, defined as a level lower than 17.8 ng/mL.
• All analyses were adjusted for seasonal variation and also for diabetes and hypertension.
• Mean age varied from 42 to 47 years, 45% to 66% were women, 48% to 91% were white, and 2% to 33% were black.
• Across decreasing quartiles of 25(OH)D levels, mean systolic and diastolic blood pressure, mean BMI, and percentages of patients with diabetes (with albumin-to-creatinine ratios and elevated C-reactive protein levels) increased and mean serum albumin levels decreased.
• Increasing age, female sex, nonwhite race (especially non-Hispanic black race), diabetes, current smoking, and increasing BMI were all independently associated with increased odds of 25(OH)D deficiency.
• Higher physical activity, use of vitamin D supplements, and season other than winter were associated with decreased odds of 25(OH)D deficiency.
• During a median of 8.7 years of follow-up, there were 1806 deaths, of which 43% were because of CVD, 23% were because of cancer, 6% were from infectious causes, and 5% were from external causes.
• Of those with CVD, 76% died of atherosclerosis, 19% of cerebrovascular disease, and 5% of congestive heart failure.
• Those who died had a mean age of 66.4 years, and 46% were women, 58% had hypertension, 19% had diabetes, and 32% had previous CVD.
• After adjusting for known CVD risk factors, those in the lowest quartile of 25(OH)D level (< 17.8 ng/mL) vs the highest quartile had a 26% higher overall rate of all-cause mortality with a mortality rate ratio of 1.26.
• Those with no history of CVD in the lowest quartile of 25(OH)D level had a stronger risk association with mortality.
• The translates to an attributable risk percentage of 20.6% and a population attributable risk percentage of 3.1% associated with the lowest quartile of 25(OH)D level.
• Although the risk for CVD was increased in the lowest quartile of 25(OH)D level, this was not statistically significant.
• Women who had both low (< 20 ng/mL) and high (> 50 ng/mL) 25(OH)D levels both had increased mortality rates.
• The authors concluded that having a 25(OH)D level in the lowest quartile was an independent predictor of mortality in men and women.

Pearls for Practice

• Risk factors for low 25(OH)D level include older age, female sex, nonwhite race, diabetes, current smoking, and higher BMI.
• A 25(OH)D level in the lowest quartile is associated with an increased risk for all-cause mortality of 26%.