Small Risk of Blood Clots With Revised Birth Control Pills
The largest study of its kind has found a small increase in the risk of dangerous blood clots associated with the use of so-called third-generation birth control pills. The pills, which were reformulated from earlier versions in an effort to reduce health risks, were the subject of a major scare in 1995 when several small studies suggested that women taking them had three times the normal risk of developing such clots, which can lead to strokes and lung damage. Subsequent analysis of that data showed the risks have been overstated, but it has not been clear what dangers, if any, were associated with the drugs.
Dr. Lene Mellemkjaer and her colleagues from the Danish Cancer Society collected data on all hospital admissions for blood clots in Denmark for people 15 to 49 between 1977 and 1993. During that period, the proportion of birth control pills that were third-generation increased from 0.2% to 66%.
The team reported in Saturday’s British Medical Journal that the incidence of admissions for clots among women rose from 120 per million person-years from 1977 to ’88 to 140 per million from 1989 to ’93. The incidence among men was the same in both periods--about 140 per million person-years indicating that there was no change in diagnostic criteria. Experts cautioned, however, that the data do not show a direct link between the pill and the increased incidence of clots.
Onions Appear to Bolster Bones
An apple a day keeps the doctor away, but an onion may be even better, according to a new study in Thursday’s Nature. The reason: It blocks the bone resorption--the naturally occurring dissolution of bone that is accelerated after menopause--associated with osteoporosis. In fact, it even increases bone density, the researchers say.
Bone biologists Roman C. Muhlbauer and Feng Li of the University of Bern in Switzerland gave male rats one gram of dried onion (the equivalent of about 3.5 ounces for a 150-pound human) per day for four weeks and found that the animals’ bone density increased by about 13.5%. In female rats with their ovaries removed to mimic menopause, the same dosage decreased bone resorption by about 25%. In both cases, the effects were much greater than those produced by dried milk or soy, both of which have previously been linked to good bone health.
The researchers found that large quantities of several other vegetables, such as broccoli, Brussels sprouts, lettuce, cucumber and garlic, were nearly as effective as onions. The pair hope to isolate the specific chemicals responsible for the effect to eliminate the need to eat several onions per day.
More AIDS Virus Cases Resistant to Drugs
Drug-resistant strains of the AIDS virus are being spread through the population by sexual contact and other means, a finding that suggests control of HIV infection may become harder in the future. Many AIDS researchers had previously believed that such resistant strains represented weaker-than-normal forms of the virus that could not be readily transmitted.
Two large groups of researchers studied subjects in New York City, Los Angeles and other metropolitan areas who had recently been infected by HIV. The findings were reported in Wednesday’s Journal of the American Medical Assn. One team found that 16% of the subjects carried a virus resistant to at least one commonly used AIDS drug, while the second found that 26% carried such a virus. Moreover, 2% of the subjects in one study and 3% in the other carried viruses resistant to a broad variety of drugs.
Osteoarthritis Study Looks at Supplements
Many of the 21 million Americans with osteoarthritis have been taking supplements containing glucosamine and chondroitin sulfate in an effort to control symptoms, even though the supplements’ efficacy has not been proved. Now, the National Institutes of Health is gearing up to conduct a major clinical trial to determine if they do any good.
The study, coordinated through the University of Utah, will enroll 1,124 patients at nine study centers across the country. None of the centers, however, are in Los Angeles. Enrollment will begin in February and results should be available about two years after that.
Hypoxemia Treatment Tested on Preemies
Adding nitric oxide to the oxygen breathed by newborns with low oxygen concentrations in their arterial blood (a condition called hypoxemia) can improve their condition, but its use is accompanied by a small risk of intracranial hemorrhage and chronic lung disease. It has not been clear, however, whether the gas produces the same benefits in premature infants with hypoxemia.
Two new studies of the subject reported in Saturday’s Lancet produced contradictory results, but suggest that the benefit, if any, in pre-term infants is small. One study conducted in France and Belgium showed that nitric oxide was beneficial in full-term newborns but had no apparent benefit in pre-term infants. The second, conducted by researchers from Children’s Hospital in Denver, found only a small benefit associated with using the gas.
One Premature Birth Means Others Likely
A woman who gives birth prematurely is much more likely than other women to have a premature delivery the next time she becomes pregnant, Swedish researchers report in Thursday’s New England Journal of Medicine.
Dr. Sven Cnattingius and his colleagues at the Karolinska Institutet in Stockholm examined the records of 243,000 women and found that a mother whose first child was born before the eighth month of pregnancy is 12 times more likely than other women to deliver another premature child. For women whose first baby was born during the eighth month, the risk of having a premature baby doubled for the next pregnancy.
The team confirmed earlier research that women who smoke face even greater risk of premature delivery. The risk was 40% higher for women who smoked up to nine cigarettes a day and 60% for those who smoked 10 or more. When women stopped smoking during their pregnancy, the risk of premature delivery returned to normal.
Medical writer Thomas H. Maugh II can be reached at thomas.maugh@latimes.com.
