|
|
|
Infections
Return to Chapter Index
Vitamin
E supplements
If you’ve been taking vitamin E supplements, you’re not
alone. The positive results of early studies on the antioxidant led many
to take it in hopes of preventing or slowing everything from respiratory
infections to macular degeneration. But what proves hopeful in early,
preliminary studies doesn’t always pan out in larger research settings,
and vitamin E is a case in point.
Age- Related Macular Degeneration
Age- Related Macular Degeneration (AMD) is the breakdown of cells of
the macula, the small part of the eye that allows us to see
things sharply and in color. Little is known about what causes AMD, which
is the leading source of vision loss in people older than 55.
Early observational studies showed vitamin E might help prevent macular
degeneration. To test this theory, researchers recruited close to 1,200
participants between the ages of 55 and 80 to receive either a daily
vitamin E supplement or a placebo for four years. Participants underwent
annual eye exams to detect signs of development or progression of AMD
and changes in visual function.
The results of this study showed the incidence of AMD was similar among
participants in the two groups. In the vitamin E group 8.6% developed
AMD, whereas 8.1% in the placebo group did. Though this study clearly
indicates that vitamin E does not help prevent or slow the progression
of AMD, the study period was short, so it doesn’t prove that vitamin
E doesn’t help in the long run.
(British Journal of Medicine, July 6, 2002)
Respiratory Infections
Early studies showed that vitamins and minerals, particularly vitamin
E, may boost immune response in healthy elderly people. With this in
mind, Dutch researchers set out to investigate whether either of the
supplements lessens the rate and severity of respiratory infections in
the elderly.
The researchers enlisted 652 participants over the age of 60 and broke
them randomly into four groups. Each day, they either took a multivitamin
with minerals and a placebo, a vitamin E pill and a placebo, both a multivitamin
with minerals and vitamin E pill, or two placebos. After fifteen months
of follow-up, the researchers found that the rate of respiratory infections
did not differ among the groups. However, those who took vitamin E supplements
actually had respiratory infections that were more severe — they
were longer, caused more symptoms, and restricted more of the sufferer’s
activities.
(Journal of the American Medical Association, August 14, 2002)
February 2003 Update
Back to Top
Lung Volume Reduction Surgery Poses
High Risk for Certain Patients
Patient eligibility for lung volume reduction surgery (LVRS),
a procedure for treating emphysema, has been modified because of early
findings from the National Emphysema Treatment Trial (NETT).
NETT, a five-year randomized study, is comparing the safety and effectiveness
of LVRS with medical treatments, such as medications and exercise rehabilitation,
in patients with advanced emphysema. The study has already found emphysema
patients who have severe lung obstruction with either limited ability
to exchange gas when breathing or damage that's evenly distributed throughout
their lungs receive little benefit, and are at an unacceptable high risk
of death from the surgery.
LRVS is believed by some to improve the ability to move air in and out
of the lungs by surgically removing up to 30 percent of the diseased
lung targeting the most damaged regions with the expectation
the remaining lung will have better air exchange. However, high-risk
patients who survived the surgery were found to have only slightly improved
functional outcomes and quality-of-life scores six months later.
As a result, NETT is no longer enrolling patients who have a forced expiratory
volume (FEV) in one second that's less than 20 percent of their predicted
value, plus one of the following characteristics: severe loss of lung
surface area or homogeneous (evenly distributed) damage to the lung caused
by the disease.
September 2001 Update
Back to Top
Pneumonia: How Long Before You Feel Better?
Pneumonia is a serious infection or inflammation of the lungs. Uncomplicated
pneumonia may be successfully treated with antibiotics in one or two
weeks, but many patients continue to experience the symptoms of pneumonia,
including cough, chest pain, fatigue, shortness of breath, and fever,
for some time after that. A team of Canadian researchers set out to determine
how long after treatment it should take for pneumonia patients to be
symptom-free.
The scientists asked a group of 535 adults who had undergone a course
of antibiotic treatment for pneumonia to complete questionnaires about
persisting symptoms at two and six weeks after the completion of their
treatment.
The average age of these patients was 62 years. Fifty-four percent of
the patients were admitted to the hospital for treatment of their pneumonia,
while a minority had a coexisting chronic illness such as chronic obstructive
pulmonary disease, asthma, or congestive heart failure.
At two weeks after therapy, 67% of patients reported fatigue, 56% were
coughing, 50% were short of breath, and 35% were producing sputum. Six
weeks after therapy, more than 60% of patients reported continuing symptoms.
Forty-five percent still had fatigue, 35% continued to cough, and 16%
had gastrointestinal symptoms. Older patients, those who were sickest
at onset of treatment, patients with chronic obstructive pulmonary disease,
and patients with asthma suffered the most persistent symptoms.
Although hospitalizations are shorter and antibiotic treatments briefer,
complete recovery still takes time. Pneumonia patients should be reassured
that a "normal" period of recuperation may vary from several
weeks to several months.
March 2001 Update
Back to Top
Zinc Lozenges Have No Beneficial Effect on the Common
Cold
Over the past few years, more and more people have begun to reach for
zinc lozenges at the first sign of a cold. But a study published in the
journal Clinical Infectious Diseases suggests that there is little
scientific evidence of zinc's effectiveness to support the treatment's
popularity.
In a study funded by Warner Lambert Consumer Healthcare, a company that
manufactures zinc lozenges, researchers conducted two clinical trials
to test zinc's efficacy. One trial involved 273 people who were exposed
to a specific cold virus, called rhinovirus, to induce a cold. The other
trial involved 281 subjects with natural colds. Both groups were broken
up into four subgroups that received one of the following treatments:
13.3 milligrams (mg) of zinc gluconate, 11.5 mg of zinc acetate, 5 mg
of zinc acetate, or a placebo. Zinc gluconate and zinc acetate are different
formulations of zinc; zinc gluconate is more commonly found in lozenges.
Treatment was started within a day of the onset of cold symptoms and
continued every 2-3 hours (up to 6 lozenges per day) until the cold symptoms
disappeared, or up to 14 days.
The researchers measured the effects of the treatments on both the duration
and severity of the colds. Patients self-scored the severity of seven
cold symptoms: sneezing, runny nose, nasal obstruction, sore throat,
cough, headache, and hoarseness.
At the end of the study, researchers found that zinc gluconate had a
small but significant effect on the duration of induced cold symptoms.
People who had taken zinc gluconate had cold symptoms for about 2.5 days
as opposed to 3.25 for high-dose zinc acetate and 3.5 days for low-dose
zinc acetate and placebo. None of the treatments, including zinc gluconate,
reduced the severity of cold symptoms for the first three days of the
cold. And none of the zinc preparations or placebo had a significant
effect on the duration or severity of symptoms in people with natural
colds.
Overall, the study suggests that zinc lozenges have little, if any, beneficial
effect on the treatment of the common cold.
January 2001 update
Back to Top
Starve a Cold, Feed a Fever, Take a Pill for
the Flu?
The height of the flu season is starting to wane, but we seem to be
at the peak of print and television ads promoting new treatments. Late
in 1999, the U.S. Food and Drug Administration approved two new anti-influenzal
drugs zanamivir (Relenza) and oseltamivir (Tamiflu). Both work by interfering
with an enzyme needed for the flu virus to reproduce. Both offer an option
for treating uncomplicated cases of the flu.
In clinical trials, when taken within two days of the onset of flu symptoms,
Relenza was shown to make people feel better a little (about 36 hours)
sooner. This drug is administered in an inhaler twice daily for five days.
Relenza has not been proved effective for people who have severe asthma
or chronic breathing problems, and in fact
Patients participating in two clinical trials reported feeling better about
one day sooner than patients taking a placebo. The most common side effects
of Tamiflu included upset stomach, vomiting, trouble sleeping, and dizziness.
Neither drug can prevent people from passing the flu on to others. These
medications may offer some relief to flu sufferers, but getting a flu vaccine
remains the best way to minimize your chances of getting this virus in
the first place. This is true for healthy people and especially for people
at high risk for complications from the flu (the elderly and people with
compromised immune systems or chronic lung diseases).
In fact, the safety and effectiveness of these new flu treatments are unproven
in these populations. What's more, Tamiflu and Relenza are effective only
against influenza types A and B, but not type C (a very common, less severe
flu) and many upper respiratory infections caught during the winter are
viral, and not the flu.
The bottom line is that these medications are helpful in only a handful
of situations. An extra day of fluids and bed rest may be all you can do.
Back to Top
|