Clinical Briefs-By Louis Kuritzky, MD

Effect of Alcohol Consumption on Myocardial Infarction

The epidemiologically ob-served favorable association between moderate alcohol consumption and cardiovascular end points has been demonstrated in multiple populations. Multiple mechanisms for this association have been proposed, though none have been confirmed in randomized, placebo-controlled, interventional trials. The current study examined participants in the Physicians’ Health Study (PHS) comparing relative risk (RR) for myocardial infarction (MI) in persons with various genetic profiles in reference to alcohol metabolism.

Comparing genetic alcohol slow-metabolizers (A-SM) with alcohol rapid metabolizers (A-RM) there was a 35% reduced risk of MI among the A-SM group. As has been previously described, moderate alcohol consumption was associated with favorable reduced incidence of MI across all genetic profiles. Of persons who consumed moderate amounts of alcohol, those with the homozygous A-SM genetic makeup enjoyed the greatest RR reduction (RR = .14). These persons also had the highest HDL levels.

Apparently, the slower metabolism of alcohol, possibly by reducing alcohol clearance, favorably affects MI risk. A-SM persons demonstrated higher HDL levels, but analysis indicated that only half of the beneficial risk reduction could be attributed to HDL. Hines and associates comment that variation in MI risk associated with genetic makeup would argue against previous thoughts that non-alcoholic components, like flavonoids, are etiologic in alcohol benefits, since only alcohol, and not flavonoids, is affected by the different alcohol dehydrogenase genetic patterns.

Hines LM, et al. N Engl J Med. 2001; 344:549-555.

Eradication of House Dust Mite from Homes of Atopic Asthmatic Subjects

Most asthmatic patients demonstrate allergic responses to inhaled allergens, of which house dust mites are the most consistent offenders. Although living in altitudes unfavorable for mites (high altitudes) favorably affects allergic symptoms, upon return to lower altitudes, symptoms recur. Mite reduction through steam cleaning and acaracides has produced transient benefit in some trials. Htut and associates report a new treatment method used in Sheffield, England, in which technicians used dry heat to achieve a mattress temperature of 80° centigrade, after which 2 minutes of steam was applied. Additionally, a ventilation system filtering air at 1 air exchange rate per hour was placed above the rooms of the actively treated participants. The placebo group received treatment with the same equipment, but no heat or steam was applied. House dust mite concentration was measured by ELISA prior to and immediately after the intervention, as well as 6 and 12 months later.

In addition to a durable reduction of dust mite concentrations in actively treated sites, bronchial hyperreactivity decreased 4-fold compared to sham-treated sites, and was maintained at this level through the 12 months duration of the trial. The cost of the heat treatment ($800) and installation of ventilation ($640) are not insubstantial.

Htut T, et al. J Allergy Clin Immunol. 2001;107:55-60.

Intake of Fruits and Vegetables and Risk of Breast Cancer

The bulk of epidemiologic evidence suggests that increased fruit and vegetable intake is associated with reduced likelihood of breast cancer. However, the strength of these observations has been affected by the potential recall and selection bias in the dominantly case-control methodologies that have been used.

To help address such issues, Smith-Warner and associates performed a pooled analysis of prospective cohort studies in which a validation study of diet intake (or similar method) was used. The population from which data was drawn included 7377 women with breast cancer among 351,825 women for whom appropriate baseline diet data was available.

No favorable association of fruit or vegetable intake was discernible in this population. Smith-Warner et al conclude that there is no relationship between fruit and vegetable intake and breast cancer.

Smith-Warner SA, et al. JAMA. 2001; 285:769-776.