The Latest News in Rheumatology
6/14/2002
Echocardiographic Evidence of Cardiac Involvement in
Ankylosing Spondylitis
Potassium's Role in Helping Prevent Osteoporosis
Researchers A. Yildirir and colleagues published their findings in a recent Clinical
Rheumatology journal on a study involving two rarely investigated heart
functions in patients with AS. They note that aortic insufficiency, myocardial
fibrosis, and conduction disturbances are known complications of AS, but much is
unknown about left ventricular diastolic function (the rhythmic expansion of the
heart as it fills with blood) and other cardiac involvement in AS patients.
Results: 88 AS patients and 31 unaffected volunteers
underwent clinical examination, echocardiography, electrocardiography, and
P-wave analysis to evaluate asymptomatic cardiac involvement. They found that
the aortic root in AS patients was larger, and the size was correlated with the duration
of the disease. Cardiac involvement could be seen in AS patients during the
asymptomatic period where there are not any clinical manifestations.
They concluded that further studies are needed to clarify the significance of
diastolic abnormalities and the value of P-wave analysis in cardiac evaluation
of patients with AS. It is generally recommended that AS patients receive a
complete examination by their physician once a year in order to detect any
complications that may be occurring before they can cause serious problems.
San Francisco, CA - In the May 2002 issue of the Journal of
Clinical Endocrinology & Metabolism, Dr. Deborah E. Sellmeyer and
colleagues at the UCSF Division of Endocrinology and the General
Clinic Research Center found that diets rich in potassium may help prevent
osteoporosis in postmenopausal women by decreasing calcium losses prompted by
high-salt intake.
Recommended consumption of sodium chloride is no more than 2400 mg daily for
cardiac health, yet Americans eat twice as much sodium chloride as they should.
The benefits of calcium and vitamin D are well established when it comes to
reducing the risk of bone loss and fracture, but this is the first study to look
at potassium's role in preventing bone density loss in relation to a high-salt
diet.
Results: 60 healthy postmenopausal women were placed on a low-salt
diet (87 mmol/d or 2000mg) for three weeks. Their level of excreted calcium and
NTX (a marker of bone resorption) were measured. After three weeks, participants
were placed on a high-salt (225 mmol/d) diet. Half were given a potassium
supplement and half were given a placebo. They continued the high salt-diet for
four weeks, and underwent more extensive testing at the end of the study.
Calcium loss increased 33% per women on placebo, but decreased 4% in the
group receiving potassium, and NTX excretion increased 23% and 7.5%
respectively, suggesting skeletal effects. They found that urine calcium and
bone turnover markers were no different on a high-salt diet with a potassium
supplement than on a low-salt diet alone.
The researchers cite that this study "provides further evidence that
recommendations regarding moderate sodium intake and increased intake of dietary
sources of potassium, namely fruits and vegetables, may also be beneficial to
postmenopausal women at risk for osteoporosis." Diets lacking in potassium
show an increase in urine calcium excretion, and potassium seems to help promote
calcium reclamation in the kidney. Thus, reducing urine calcium excretion and
NTX to the extent seen in this study may be achieved by consuming 7-8 servings
of potassium-rich fruits and vegetables every day.