ORAL CONTRACEPTIVES A HEALTH RISK ONLY IN SMOKERS

A long-term study of 17,032 women demonstrated that oral contraceptive use has no overall harmful effects on women’s health. However, smoking significantly increases mortality, even in comparatively young women.

The study recruited women from 17 family planning clinics between 1968 and 1974 and followed them until December 31, 2000. Mortality rates were calculated based not only on whether the women had used oral contraceptives or cigarettes but also on the duration of oral contraceptive use and the number of cigarettes smoked daily.

A total of 889 deaths occurred during 479,400 woman-years of follow-up. In comparison to other women, oral contraceptive users had an increased risk of cervical cancer but a decreased risk of ovarian cancer; no overall difference in cancer-related mortality between the two groups could be detected. Oral contraceptive use increased the risk of death from ischemic heart disease only among heavy smokers.

In comparison, smoking increased the risk of death from lung cancer 20-fold in light smokers and almost 40-fold in heavy smokers. It also increased the risk of death from ischemic heart disease, hemorrhagic stroke, other forms of stroke, respiratory disease, and disorders of the liver, gallbladder, or pancreas. The excess mortality associated with smoking could be seen in women as young as 35 to 44.

Vessey M, Painter R, Yeates D. Mortality in relation to oral contraceptive use and cigarette smoking. Lancet. 2003;362:185-191.

BREATHING EXERCISE IMPROVES ASTHMA SYMPTOMS

The Buteyko breathing technique, a yoga-like exercise designed to reduce the frequency and depth of breathing, may improve asthma symptoms and lessen the need for a bronchodilator, a new study showed. However, it has no overall effect on bronchial hyperresponsiveness or lung function.

Cooper et al studied 90 asthmatic adults to compare the effects of the Buteyko technique, the Pink City Lung Exerciser (a device that reduces breathing frequency and increases the length of exhalation), and a placebo device.

The primary efficacy outcomes were symptom scores and response to methacholine challenge at six months. Secondary outcomes included forced expiratory volume in one second, rate of asthma exacerbations, quality of life, and use of bronchodilators or inhaled corticosteroids.

By the end of the study, asthma symptoms and ß-agonist use were markedly lower in the Buteyko group than in the other two groups. In addition, one of the eight quality-of-life dimensions studied (asthma-induced role limitations) showed greater improvement in the Buteyko group than in the other groups. No other difference among the groups was seen.

The authors concluded that the Buteyko technique provides some benefit to asthma patients. However, because the technique requires time, motivation, and commitment from both patients and their physicians, it should be recommended only to appropriate patients.

Cooper S, Oborne J, Newton S, et al. Effect of two breathing exercises (Buteyko and pranayama) in asthma: a randomised controlled trial. Thorax. 2003;58:674-679.

POTENTIATED DESENSITIZATION THERAPY INEFFECTIVE FOR SEASONAL ALLERGIES

Allergen-specific immunotherapy using enzyme-potentiated desensitization does not appear to ameliorate allergy symptoms, according to a recent double-blind, randomized, placebo-controlled trial.

Radcliffe et al evaluated 176 adults with a history of severe summer hay fever and a positive skin test to timothy grass pollen. The groups received two injections, given eight to 11 weeks apart, of mixed inhaled allergen extracts or placebo. At baseline and six to eight weeks after the last injection, patients’ sensitivity to grass pollen was measured using quantitative skin tests in which the amount of allergen increased until hay fever symptoms appeared. Before and during the treatment period, patients recorded their allergy symptoms.

The two primary outcome measurements—the proportion of symptom-free days and the posttreatment rhinosinusitis score—did not differ between the groups at any time, nor did the mean overall quality of life. Interestingly, 44% of the patients given active treatment experienced rash or itching at the injection site, compared with 8% of the placebo group. Previous researchers had observed a marked lack of itching after desensitization injections. Radcliffe et al speculated that the rash and itching may have resulted in a loss of blinding between treatments; however, they added that such a loss would be more likely to increase the estimated efficacy of active treatment than to decrease it.

Although previous trials reported a treatment effect with desensitization therapy, the current study showed no such effect on hay fever symptoms.

Radcliffe MJ, Lewith GT, Turner RG, et al. Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study. BMJ. 2003;327:251-254.

DO COCHLEAR IMPLANTS INCREASE MENINGITIS RISK?

The use of cochlear implants may increase a child’s risk for bacterial meningitis, indicated a cohort study involving 4,264 implant recipients.

The study, conducted by Reefhuis et al, included two types of analysis. A cohort design was used to determine meningitis incidence, and a nested case-control design was employed to investigate risk factors.

All children in the study had received their implants between 1999 and 2002 and were 5 or younger at the time of the operation. Bacterial meningitis developed in 26 of these children; two thirds of these cases were caused by Streptococcus pneumoniae.

The risk of bacterial meningitis was 4.5 times higher in the children who had received an implant with a positioner than in those whose implants did not include a positioner. The increased risk associated with a positioner persisted throughout the two years of follow-up. The only other independent risk factor for bacterial meningitis was inner-ear malformation with a cerebrospinal fluid leak.

The incidence of streptococcal meningitis—in comparison to that in the general population—was 30 times higher in the children whose implants had a positioner and 16 times higher in the children whose implants did not include a positioner. According to the authors, this finding indicated that the increased incidence of S pneumoniae meningitis associated with cochlear implants was not entirely explained by the use of a positioner.

Based on their results, Reefhuis et al do not recommend that implants with positioners be removed; the risks associated with removal may be greater than the risks presented by the positioner. However, they do suggest that all children who are candidates for cochlear implants receive the pneumococcal vaccine according to the schedule for high-risk children; vaccination should take place at least two weeks before surgery.

Reefhuis J, Honein MA, Whitney CG, et al. Risk of bacterial meningitis in children with cochlear implants. N Engl J Med. 2003;349:435-445.

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