Low
vitamin D linked to high risk of death from all causes including cancer and
cardiovascular disease
The main source of vitamin D is its
production in skin thanks to the sun. Women are more prone to low vitamin D
than men - and due to differing weather conditions, concentrations vary in
populations across the world.
Vitamin D deficiency is especially common
among the elderly who often have less sun exposure, but it is unclear what
effect the production of vitamin D has on death.
So researchers investigated the
association of vitamin D with deaths from all-causes, cardiovascular diseases
and cancer. They paid particular attention to differences between countries,
sexes and age groups.
Data were taken from seven population-based
cohorts from the US and across Europe. All study participants were aged 50-79.
Results reported in BMJ-British Medical Journal June 2014 show that there was no clear
trend of vitamin D by age, but average levels were consistently lower among women
than men. Average levels increased with education, were lowest in obese
individuals and higher among subjects who exercised.
During 16 years of follow-up, there were
6,695 deaths in 26,018 patients - 2,624 from cardiovascular diseases and 2,227
from cancer.
An association was found between those
with the lowest levels of vitamin D and death from cardiovascular disease - in
people with and without a history of the disease- and deaths from cancer in
those with a history of the disease. No association was found between low
vitamin D levels and deaths from cancer in those without a history of the
disease.
The researchers say this shows an
important role of vitamin D in the prognosis of cancer, although they add
"we cannot exclude reverse causality, that is, that the cancer might have
led to low vitamin D levels." There was also a dose-response relationship
which was unchanged after excluding patients with a history of cardiovascular
disease and cancer.
The researchers say that death from all
causes as a result of low vitamin D has "high public health
relevance" and should be given high priority. They also ask whether levels
of vitamin D in specific countries, different sexes and seasons "should be
considered for defining vitamin D deficiency" due to its varying levels.
They conclude that those with the lowest
levels of vitamin D had an association "with increased all-cause
mortality, cardiovascular mortality, and cancer mortality (in subjects with a
history of cancer)." They say these effects were consistent across
countries, sexes, age groups, and time of the year when blood tests were done
and that "variation by geographic region, sex and season might need to be
taken into account."
Lower vitamin D level in
blood linked to higher premature death rate
Researchers
at the University of California, San Diego School of Medicine have found that
persons with lower blood levels of vitamin D were twice as likely to die
prematurely as people with higher blood levels of vitamin D.
The
finding, published in the June 12, 2014 issue of American Journal of Public Health, was based on a systematic review
of 32 previous studies that included analyses of vitamin D, blood levels and
human mortality rates. The specific variant of vitamin D assessed was
25-hydroxyvitamin D, the primary form found in blood.
"Three
years ago, the Institute of Medicine (IOM) concluded that having a too-low
blood level of vitamin D was hazardous," said Cedric Garland, DrPH,
professor in the Department of Family and Preventive Medicine at UC San Diego
and lead author of the study. "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. "
Garland
said the blood level amount of vitamin D associated with about half of the
death rate was 30 ng/ml. He noted that two-thirds of the U.S. population has an
estimated blood vitamin D level below 30 ng/ml.
"This
study should give the medical community and public substantial reassurance that
vitamin D is safe when used in appropriate doses up to 4,000 International
Units (IU) per day," said Heather Hofflich, DO, professor in the UC San
Diego School of Medicine's Department of Medicine.
"However,
it's always wise to consult your physician when changing your intake of vitamin
D and to have your blood level of 25-hydroxyvitamin D checked annually. Daily
intakes above 4,000 IU per day may be appropriate for some patients under
medical supervision."
The
average age when the blood was drawn in this study was 55 years; the average
length of follow-up was nine years. The study included residents of 14
countries, including the United States, and data from 566,583 participants.
Vitamin
D deficiency increases mortality after cardiac arrest
Lack of vitamin D also increases poor brain function after
cardiac arrest sevenfold
Vitamin
D deficiency increases the risk of poor brain function after sudden cardiac
arrest by seven-fold, according to research presented at Acute Cardiovascular
Care 2014 by Dr Jin Wi from Korea. Vitamin D deficiency also led to a higher
chance of dying after sudden cardiac arrest.
Acute
Cardiovascular Care is the annual meeting of the Acute Cardiovascular Care
Association (ACCA) of the European Society of Cardiology (ESC) and takes place
18-20 October in Geneva, Switzerland.
Dr
Wi said: "In patients resuscitated after sudden cardiac arrest, recovery
of neurological function is very important, as well as survival. Vitamin D
deficiency has been reported to be related to the risk of having various
cardiovascular diseases, including sudden cardiac arrest. We investigated the
association of vitamin D deficiency with neurologic outcome after sudden
cardiac arrest, a topic on which there is no information so far."
The
researchers prospectively analysed clinical data from all unconscious patients
resuscitated from sudden cardiac arrest of presumed cardiac cause at Severance
Cardiovascular Hospital in Seoul, Korea. Neurologic outcome was assessed by the
Cerebral Performance Category (CPC) score at 6 months after discharge.1 Good
neurologic outcome was defined as a CPC score of 1 or 2, whereas poor
neurological outcome was defined as a CPC score of 3 to 5. Vitamin D deficiency
was defined as 25-hydroxyvitamin D less than 10 ng/mL.
The
study included 53 patients. Bystander cardiopulmonary resuscitation (CPR) was
performed in 41 patients (77%). The first monitored heart rhythm was shockable
in 36 patients (68%) and non-shockable in 17 patients (32%). The average
vitamin D level was 10.3 ng/mL and 31 patients (59%) were deficient.
Patients
with a poor neurological outcome had a significantly lower vitamin D level (7.9
ng/mL) compared to those with a good neurological outcome (12.4 ng/mL)
(p=0.002). The researchers found that 65% of patients with vitamin D deficiency
had a poor neurological outcome at 6 months after discharge compared to 23% of
patients with healthy vitamin D levels. They also found that 29% of patients
with vitamin D deficiency had died at 6 months compared to none of the patients
with good vitamin D levels (p=0.007).
Dr
Wi said: "Patients with vitamin D deficiency were more likely to have a
poor neurological outcome or die after sudden cardiac arrest than those who
were not deficient. Nearly one-third of the patients who were deficient in
vitamin D had died 6 months after their cardiac arrest, whereas all patients
with sufficient vitamin D levels were still alive."
The
researchers conducted a multivariate logistic analysis to assess the impact of
a number of factors on neurological outcome after sudden cardiac arrest. They
found that vitamin D deficiency independently predicted poor neurological
outcome with an odds ratio of 7.13.
Dr
Wi said: "Vitamin D deficiency increased the risk of poor neurological
outcome after sudden cardiac arrest by 7-fold. The only factors that had a
greater impact on poor neurological outcome were the absence of bystander CPR
or having a first monitored heart rhythm that was non-shockable."
He
added: "Our findings suggest that vitamin D deficiency should be avoided,
especially in people with a high risk of sudden cardiac arrest. People are at
higher risk if they have a personal or family history of heart disease
including heart rhythm disorders, congenital heart defects and cardiac arrest.
Other risk factors for cardiac arrest include smoking, obesity, diabetes, a
sedentary lifestyle, high blood pressure and high cholesterol, and drinking too
much alcohol."
Dr Wi continued: "Vitamin D is found in oily fish, such
as salmon, sardines, and mackerel, eggs, fortified fat spreads, fortified
breakfast cereals and powdered milk. Most of our vitamin D stores are made by
the body when our skin reacts to sunlight."
Low vitamin D levels linked to increased risks after noncardiac surgery
Death and serious complications
more likely in patients with vitamin D deficiency, study suggests
August 15, 2014 – Patients with low blood
levels of vitamin D are at increased risk of death and serious complications
after noncardiac surgery, suggests a study in Anesthesia & Analgesia.
"Vitamin D concentrations were
associated with a composite of in-hospital death, serious infections, and
serious cardiovascular events," according to the new research by Dr
Alparslan Turan and colleagues of the Cleveland Clinic. They believe their
results warrant further study to see if giving vitamin D supplementation before
surgery can reduce the risk of these adverse outcomes.
Lower Vitamin D Levels Linked to Higher
Surgical Risk
The researchers analyzed the relationship
between vitamin D level and surgical outcomes in approximately 3,500 patients
who underwent operations other than heart surgery between 2005 and 2011. Only
patients who had available data on vitamin D levels around the time of
surgery—from three months before to one month afterward—were included in the
study.
The concentration of vitamin D (specifically,
25-hydroxyvitamin D) in blood samples was analyzed as a risk factor for death,
cardiovascular events, or serious infections while in the hospital. The
analysis included adjustment for other factors such as demographic
characteristics, medical conditions, and type and duration of surgery.
Most patients did not meet the recommended
25-hydroxyvitamin D concentration of greater than 30 nanograms per milliliter
(ng/mL). The median vitamin D level was 23.5 ng/mL—more than 60 percent of
patients were in the range of vitamin D insufficiency (10 to 30 ng/mL). Nearly
20 percent had vitamin D deficiency (less than 10 ng/mL).
"Higher vitamin D concentrations were
associated with decreased odds of in-hospital mortality/morbidity," the
researchers write. For each 5 ng/mL increase in 25-hydroxyvitamin D level, the
combined risk of death, cardiovascular events, or serious infections decreased
by seven percent.
Patients at the lowest level of
25-hydroxyvitamin D (less than 13 ng/mL) were at highest risk of death or serious
complications. Those with higher vitamin D levels (up to 44 ng/mL) had about
half the risk as those in the lowest group. The association with low vitamin D
was statistically significant only for cardiovascular complications, although
there were "strong trends" for mortality and infections.
Further Study Needed to Determine Cause and
Effect
"Vitamin D deficiency is a global
health problem," according to Dr Turan and coauthors. In addition to
protective cardiovascular and neurological effects, vitamin D plays an
important role in the immune system.
The high rates of vitamin D insufficiency
and deficiency in the surgical patients studied are consistent with previous
findings in the general population. In recent years, studies have suggested
that vitamin D levels may affect a wide range of health outcomes.
Patients undergoing surgery are at risk of
cardiovascular and infectious complications, both of which may be aggravated by
vitamin D deficiency. Previous studies found no increased risk of adverse
outcomes related to vitamin D levels in patients undergoing cardiac surgery. It
may be that the tissue injury and inflammation associated with heart surgery
overwhelms any potential protective effect of vitamin D.
However, Dr Turan and colleagues note that
their study had some important limitations of their study—especially the fact
that it included only patients who had recent measurements of vitamin D levels.
They may represent a less-healthy group, introducing a potential source of
selection bias.
The study can't determine whether there is any
cause-and-effect relationship between vitamin D levels and the risk of adverse
outcomes. Dr Turan and colleagues suggest a formal randomized trial to evaluate
whether preoperative vitamin D supplementation can reduce the risk of serious
complications and death after surgery.
Low levels of vitamin D are associated with mortality in older adults
Low levels of vitamin D and high levels
of parathyroid hormone are associated with increased mortality in African
American and Caucasian older adults, according to a new study accepted for
publication in The Endocrine Society's
Journal of Clinical Endocrinology and Metabolism (JCEM). The study also
indicates that the potential impact of remediating low vitamin D levels is
greater in African Americans than Caucasians because vitamin D insufficiency is
more common in African Americans.
For the past several years, there has
been considerable interest in the role vitamin D plays in improving health and
preventing disease. Low levels of vitamin D have been directly associated with
various forms of cancer and cardiovascular disease. Most studies regarding the
health effects of low vitamin D levels have been conducted on persons of
European origin, but the current study examines the relationship between
vitamin D and mortality in blacks and whites.
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In this study, 2,638 Caucasians and
African-Americans aged 70-79 years were asked to fast for 12-hours, after which
a blood sample was collected to determine levels of vitamin D. Every six months
study participants were contacted to ascertain their medical condition. This
study determined the proportion of deaths among participants of with different
vitamin D levels. In addition to many health factors, the time of year was also
taken into account due to the seasonal ntiaeffects on vitamin D. Researchers
found that levels of vitamin D less than 30 ng/ml were associated with
significantly increased all-cause mortality.
"We all know that good nutrition is
important to overall health and our study adds to a growing body of literature
that underscores the importance of vitamin D and indicates that poor vitamin D
nutrition is wide-spread," said Kritchevsky. "The good news is it's
easy to improve vitamin D status either through increased skin exposure to sunlight
or through diet or supplements."
Low
levels of vitamin D can mean a much greater risk of death.
A new study concludes that among older
adults – especially those who are frail – low levels of vitamin D can mean a
much greater risk of death.
The randomized, nationally representative
study found that older adults with low vitamin D levels had a 30 percent
greater risk of death than people who had higher levels.
Overall, people who were frail had more
than double the risk of death than those who were not frail. Frail adults with
low levels of vitamin D tripled their risk of death over people who were not
frail and who had higher levels of vitamin D.
“What this really means is that it is
important to assess vitamin D levels in older adults, and especially among
people who are frail,” said lead author Ellen Smit of Oregon State University.
Smit said past studies have separately
associated frailty and low vitamin D with a greater mortality risk, but this is
the first to look at the combined effect. This study, published online in the European Journal of Clinical Nutrition,
examined more than 4,300 adults older than 60 using data from the Third
National Health and Nutrition Examination Survey.
“Older adults need to be screened for
vitamin D,” said Smit, who is a nutritional epidemiologist at OSU’s College of
Public Health and Human Sciences. Her research is focused on diet, metabolism,
and physical activity in relation to both chronic disease and HIV infection.
“As you age, there is an increased risk
of melanoma, but older adults should try and get more activity in the
sunshine,” she said. “Our study suggests that there is an opportunity for
intervention with those who are in the pre-frail group, but could live longer,
more independent lives if they get proper nutrition and exercise.”
Frailty is when a person experiences a
decrease in physical functioning characterized by at least three of the
following five criteria: muscle weakness, slow walking, exhaustion, low
physical activity, and unintentional weight loss. People are considered
“pre-frail” when they have one or two of the five criteria.
Because of the cross-sectional nature of
the survey, researchers could not determine if low vitamin D contributed to
frailty, or whether frail people became vitamin D deficient because of health
problems. However, Smit said the longitudinal analysis on death showed it may
not matter which came first.
“If you have both, it may not really
matter which came first because you are worse off and at greater risk of dying
than other older people who are frail and who don’t have low vitamin D,” she
said. “This is an important finding because we already know there is a
biological basis for this. Vitamin D impacts muscle function and bones, so it
makes sense that it plays a big role in frailty.”
The study divided people into four
groups. The low group had levels less than 50 nanomole per liter; the highest
group had vitamin D of 84 or higher. In general, those who had lower vitamin D
levels were more likely to be frail.
About 70 percent of Americans, and up to
a billion people worldwide, have insufficient levels of vitamin D. And during
the winter months in northern climates, it can be difficult to get enough just
from the sun. OSU’s Linus Pauling Institute recommends adults take 2,000 IU of
supplemental vitamin D daily. The current federal guidelines are 600 IU for
most adults, and 800 for those older than 70.
“We want the older population to be able
to live as independent for as long as possible, and those who are frail have a
number of health problems as they age,” Smit said. “A balanced diet including
good sources of vitamin D like milk and fish, and being physically active
outdoors, will go a long way in helping older adults to stay independent and
healthy for longer.”
Vitamin D can help elderly women survive
Giving vitamin D3 (cholecalciferol) to
predominantly elderly women, mainly in institutional care, seems to increase
survival. These women are likely to be vitamin D deficient with a significant
risk of falls and fractures. This is the key conclusion in a systematic review
published in The Cochrane Library.
Up until now there has been no clear view
on whether there is a real benefit of taking vitamin D. "A Cochrane
meta-analysis published only a couple of years ago found that there was some
evidence for benefit, but it could not find an effect on mortality. We were,
however, aware that more trials had been published and wanted to assess the
effects of vitamin D when you added all the data together," said Dr Goran
Bjelakovic, who works at Department of Internal Medicine - Gastroenterology and
Hepatology, at the University of Nis, in Serbia and at The Cochrane
Hepato-Biliary Group at The Copenhagen Trial Unit in Copenhagen, Denmark.
The eight-strong international team of
researchers identified 50 randomised trials that together had 94,148
participants. They had a mean age of 74 years, and 79% were women. "Our
analyses suggest that vitamin D3 reduces mortality by about 6%. This means that
you need to give about 200 people vitamin D3 for around two years to save one
additional life," says Bjelakovic.
There were no significant benefits of
taking other forms of vitamin D such as vitamin D2, and the active forms of the
vitamin, alfacalcidol or calcitriol. However, the researchers point out that
they could only find much less data relating to these types of vitamin D and so
these conclusions should be taken with caution. "We need to have more
randomised trials that look specifically to see whether these forms of vitamin
D do or don't have benefits," says Bjelakovic. His team did conclude that
alfacalcidol and calcitriol significantly increased the risk of hypercalcaemia,
and vitamin D3 combined with calcium significantly increased the risk of kidney
stones.
There have been reports and comments that
taking vitamin D can reduce the risk of getting cancer, but this work showed no
evidence that vitamin D reduced cancer-related mortality.
"Previous reviews of preventive
trials of vitamin D have not included as much information and have not examined
the separate influence of different forms of vitamin D on mortality. By taking
data from a larger number of trials we have been able to shed much more light
on this important issue," says Bjelakovic.
Vitamin D deficiency associated with increased mortality
A new study published in the journal Respirology reveals that adult patients
admitted to the hospital with pneumonia are more likely to die if they have
Vitamin D deficiency.
Vitamin D is known to be involved in the
innate immune response to infection.
The team of researchers at Waikato
Hospital and the Universities of Waikato and Otago, measured vitamin D in the
blood samples of 112 adult patients admitted with community acquired pneumonia
during the winter at the only acute-care hospital in Hamilton, New Zealand.
The researchers found that Vitamin D
deficiency was associated with higher mortality within the first 30 days after
hospital admission for pneumonia. The association between vitamin D deficiency
was not explained by patient age, sex, comorbidities, the severity of the
systemic inflammatory response, or other known prognostic factors.
The authors conclude that "improved
understanding of Vitamin D and its role in immunity may lead to better ways to
prevent and/or treat pneumonia. We now need to investigate whether Vitamin D
supplements could be a useful addition to pneumonia treatment and whether using
supplements could help to prevent or reduce the severity of pneumonia among
high-risk populations."
Less Vitamin D Means Higher Mortality After Heart Failure
Survival rates in heart failure patients
with reduced levels of vitamin D are lower than in patients with normal levels.
This is the finding of a major study carried out at University Medical Center,
Groningen, Netherlands, according to a presentation at the European Society of
Cardiology's Congress 2010 in Stockholm.
Results also suggest that low levels of
vitamin D are associated with activation of the Renin Angiotensin System (RAS
-- a pivotal regulatory system in heart failure) and an altered cytokine
profile.
Vitamin D is produced by the skin when it
is exposed to the natural Ultra Violet-B (UV-B) radiation from the sun. Low
levels have long been known as the underlying mechanism of rickets however, in
recent years, new studies have provided novel insight into the multiple
vitamin's functions. It has been proved that most tissues and cells have a
vitamin D receptor, and there is strong evidence that its presence plays a part
in reducing the risk factor profiles of several chronic illnesses, such as
common cancers, autoimmune diseases, kidney diseases, chronic infectious
diseases, hypertension and apparently also heart failure.
"By showing that vitamin D is an
independent predictor, we hoped to prove that it is a contributory factor to,
rather than peripheral to, the development and prognosis of heart
failure," said Ms. Licette Liu of the University Medical Center,
Groningen. "With this new information, we then hope to provide better
insight into the pathophysiology of heart failure."
Experiments with mice lacking the vitamin
D receptor have shown typical signs of heart failure, while small-scale
clinical studies have shown that low levels are a consistent factor amongst
human heart failure patients. "There are several potential reasons for low
vitamin D levels in heart failure patients, including the fact that they are
often bedridden or house-bound due to their clinical symptoms" Ms. Liu
explains. "This would lead to a serious deficiency, because 80-90 percent
of vitamin D is obtained by UV-B radiation. Another factor is that the capacity
of the skin to produce vitamin D declines with age, and as heart failure has a
high incidence among elderly people, it is not entirely surprising to measure
low levels. Furthermore, severe heart failure is associated with impaired renal
function due to decreased blood supply. This may be responsible for a reduced
synthesis of the active form of vitamin D, since the final step of conversion
takes place in the kidneys. All of these factors may add to vitamin D
deficiency in heart failure patients."
Observations in animal studies suggest
that vitamin D is a negative regulator of the RAS, which is responsible for
volume and blood pressure homeostasis and is a pivotal regulatory system in
heart failure. Low levels may activate the RAS, which in turn may contribute to
the development and progression of heart failure. There is also growing
evidence that overproduction of several pro-inflammatory cytokines (and
underproduction of anti-inflammatory cytokines) plays an important role in
heart failure. Several studies have shown that vitamin D alters the cytokine
profile and may therefore contribute to the inflammatory processes in heart
failure.
In the current study, vitamin D
concentration was assessed in plasma samples from 548 heart failure patients,
using data supplied by the Coordinating study evaluating Outcomes of Advising
and Counselling in Heart failure (COACH). Results showed that vitamin D
concentration is associated with the prognosis of heart failure. Patients with
lower concentrations had a higher risk of death or required re-hospitalisation,
whereas patients with higher concentrations had lower survival risks for these
endpoints. Further, significant correlations between vitamin D, and Plasma Renin
Activity and C-Reactive Protein were found. These correlations suggest that the
association between vitamin D and the prognosis in heart failure may be
explained by activation of the RAS and an altered cytokine profile.
This is the first study in a large cohort
of patients recruited due to hospitalisation for heart failure, in which the
role of vitamin D has been determined, along with the roles of plasma renin
activity and cytokines. Previous reports involved smaller study cohorts, and
did not determine either plasma renin activity or cytokines, or they included
patients who were referred routinely for coronary angiography at baseline.
The major limitation of this
observational study was that bystander and indirect effects of variables could
not be discounted. Therefore, a prospective randomised intervention study is
necessary to investigate the effect of vitamin D on the RAS, cytokines profile
and, finally, on the prognosis in heart failure patients. Ms. Liu concludes,
"This study provides compelling evidence that a high vitamin D status is
associated with improved survival in heart failure patients. Until an
intervention study has been designed and completed, it seems that we should
advise patients with heart failure to maintain appropriate vitamin D levels by
taking supplements, by eating oily fish or eggs, or simply by exposure to
sunlight."
Vitamin
D deficiency linked to higher mortality in female nursing home residents
The majority of institutionalized elderly
female patients are vitamin D deficient and there is an inverse association of
vitamin D deficiency and mortality, according to a study accepted for published
in The Endocrine Society's Journal of
Clinical Endocrinology and Metabolism (JCEM).
Recommendations for dietary vitamin D
intake in the elderly are higher than any other age group because vitamin D
deficiency is extraordinarily prevalent in this population and is considered a
causal risk factor for skeletal diseases. Treatment involves the daily
ingestion of up to 800 IU of vitamin D. The current study examined whether
vitamin D deficiency is an independent risk factor for mortality in
institutionalized elderly patients.
"Our findings show that the vast
majority of nursing home residents are severely vitamin D deficient and those
with the lowest vitamin D levels are at high risk of mortality," said Dr.
Stefan Pilz, MD, of the Medical University of Graz, Austria, and lead author of
the study. "This situation warrants immediate action to prevent and treat
vitamin D deficiency."
In this study, researchers examined a
sample of 961 nursing home residents in Austria, with an average age of 83.7
years. The researchers recorded 284 deaths—or 30 percent of the study
cohort—after a mean follow-up time of 27 months. Their findings showed that vitamin
D levels were below recommended levels in 92.8 percent of the study
participants, suggesting that while vitamin D deficiency among frail and
elderly populations has been acknowledged for several decades, no effective
strategies to treat the deficiencies have been developed and implemented.
"Vitamin D supplementation in these
patients can exert significant benefits on clinically relevant outcomes such as
fractures," said Pilz. "In light of our findings, and the existing
literature on adverse effects of vitamin D deficiency, there exists now an
urgent need for effective strategies to improve vitamin D status in older
institutionalized patients.
Study
finds inadequate levels of Vitamin D may significantly increase risk of stroke,
heart disease and death
While mothers have known that feeding
their kids milk builds strong bones, a new study by researchers at the Heart
Institute at Intermountain Medical Center in Salt Lake City suggests that
Vitamin D contributes to a strong and healthy heart as well – and that
inadequate levels of the vitamin may significantly increase a person's risk of
stroke, heart disease, and death, even among people who've never had heart
disease.
For more than a year, the Intermountain
Medical Center research team followed 27,686 patients who were 50 years of age
or older with no prior history of cardiovascular disease. The participants had
their blood Vitamin D levels tested during routine clinical care. The patients
were divided into three groups based on their Vitamin D levels – normal (over
30 nanograms per milliliter), low (15-30 ng/ml), or very low (less than 15
ng/ml). The patients were then followed to see if they developed some form of
heart disease.
Researchers found that patients with very
low levels of Vitamin D were 77 percent more likely to die, 45 percent more
likely to develop coronary artery disease, and 78 percent were more likely to
have a stroke than patients with normal levels. Patients with very low levels
of Vitamin D were also twice as likely to develop heart failure than those with
normal Vitamin D levels.
Findings from the study were presented at
the American Heart Association's 2009 Scientific Conference.
"This was a unique study because the
association between Vitamin D deficiency and cardiovascular disease has not
been well-established," says Brent Muhlestein, MD, director of
cardiovascular research of the Heart Institute at Intermountain Medical Center
and one of the authors of the new study. "Its conclusions about how we can
prevent disease and provide treatment may ultimately help us save more
lives."
A wealth of research has already shown
that Vitamin D is involved in the body's regulation of calcium, which
strengthens bones — and as a result, its deficiency is associated with
musculoskeletal disorders. Recently, studies have also linked Vitamin D to the
regulation of many other bodily functions including blood pressure, glucose
control, and inflammation, all of which are important risk factors related to
heart disease. From these results, scientists have postulated that Vitamin D
deficiency may also be linked to heart disease itself.
"Utah's population gave us a unique
pool of patients whose health histories are different than patients in previous
studies," Dr. Muhlestein says. "For example, because of Utah's low
use of tobacco and alcohol, we were able to narrow the focus of the study to
the effects of Vitamin D on the cardiovascular system."
The results were quite surprising and
very important, says Heidi May, PhD, MS, an epidemiologist with the Intermountain
Medical Center research team and one of the study authors.
"We concluded that among patients 50
years of age or older, even a moderate deficiency of Vitamin D levels was
associated with developing coronary artery disease, heart failure, stroke, and
death," she says. "This is important because Vitamin D deficiency is
easily treated. If increasing levels of Vitamin D can decrease some risk
associated with these cardiovascular diseases, it could have a significant
public health impact. When you consider that cardiovascular disease is the
leading cause of death in America, you understand how this research can help
improve the length and quality of people's lives."
Sunshine could benefit health and prolong life
Exposing skin to sunlight may help
to reduce blood pressure, cut the risk of heart attack and stroke – and even
prolong life, a study suggests.
Researchers have shown that when our
skin is exposed to the sun's rays, a compound is released in our blood vessels
that helps lower blood pressure.
The findings suggest that exposure
to sunlight improves health overall, because the benefits of reducing blood
pressure far outweigh the risk of developing skin cancer.
The study has been carried out by
the University of Edinburgh.
Heart disease and stroke linked to
high blood pressure are estimated to lead to around 80 times more deaths than
those from skin cancer, in the UK.
Production of this pressure-reducing
compound – called nitric oxide – is separate from the body's manufacture of
vitamin D, which rises after exposure to sunshine. Until now it had been
thought to solely explain the sun's benefit to human health, the scientists
add.
Researchers studied the blood
pressure of 24 volunteers who sat beneath tanning lamps for two sessions of 20
minutes each. In one session, the volunteers were exposed to both the UV rays
and the heat of the lamps. In the other, the UV rays were blocked so that only
the heat of the lamps affected the skin.
The results showed that blood
pressure dropped significantly for one hour following exposure to UV rays, but
not after the heat-only sessions. Scientists say that this shows that it is the
sun's UV rays that lead to health benefits. The volunteers' vitamin D levels
remained unaffected in both sessions.
Dr Richard Weller, Senior Lecturer
in Dermatology at the University of Edinburgh, said: "We suspect that the
benefits to heart health of sunlight will outweigh the risk of skin cancer. The
work we have done provides a mechanism that might account for this, and also
explains why dietary vitamin D supplements alone will not be able to compensate
for lack of sunlight.
"We now plan to look at the
relative risks of heart disease and skin cancer in people who have received
different amounts of sun exposure. If this confirms that sunlight reduces the
death rate from all causes, we will need to reconsider our advice on sun
exposure."
