CIGARETTES AND ALCOHOL ELEVATE ALT LEVELS IN HEPATITIS C

Alcohol consumption and hepatitis C virus (HCV) may have a synergistic effect on alanine aminotransferase (ALT) levels. However, the effect of smoking on ALT activity among people with HCV or hepatitis B (HBV) infection is not well understood.

To investigate these issues, Wang et al surveyed a community with hyperendemic HBV and HCV, using a questionnaire that included demographics, frequency of cigarette and alcohol use, and history of blood transfusion. Serum samples were obtained and tested for hepatitis B surface antigen (HBsAg), anti-HCV markers, and ALT levels.

Of the 6,095 participants, 9.2% had elevated ALT concentrations. In comparison to seronegative subjects, HBsAg-seropositive subjects were three times more likely to have elevated ALT levels; anti-HCV–seropositive subjects were 11 times more likely.

Among the seronegative subjects, male gender, frequent alcohol consumption, and a history of blood transfusion all increased the likelihood of elevated ALT levels. None of the risk factors studied was shown to influence this likelihood among HBsAg-seropositive subjects. In contrast, among the anti-HCV–seropositive subjects, both frequent alcohol consumption and cigarette smoking conferred an increase in risk, and the effects of the two were additive (Figure 1).

Wang et al admit that levels of cigarette and alcohol consumption were self-reported, which could have resulted in a bias toward underestimation. These investigators conclude that alcohol use and cigarette smoking should be avoided by anti-HCV–seropositive individuals because they may exacerbate hepatic dysfunction.

Wang C-S, Wang S-T, Chang T-T, et al. Smoking and alanine aminotransferase levels in hepatitis C virus infection. Arch Intern Med. 2002;162:811-815.

Figure 1 How Smoking and Drinking Increase the Risk of Liver Damage in Anti-HCV–Seropositive Subjects*

* Heavy smoking was defined as more than one pack per day; light smoking as less than that amount. Definitions of alcohol consumption were not included in the study. HCV, hepatitis C virus; ALT, alanine aminotransferase. Adapted from Wang et al. Arch Intern Med. 2002.

Nearly half of the 450,000 adults admitted to the hospital each year for acute asthma are sensitized to allergens. Viral infections can also aggravate asthma, and a relationship between allergens and viruses has been observed in experimental studies. Green et al conducted a case-control study to investigate sensitization/exposure to allergens and viral infection in adults with acute asthma.

Fifty-seven adults admitted to the hospital for acute asthma were each matched with two controls—one outpatient with stable asthma and one inpatient with a non-respiratory condition. Skin tests and nasal lavage were performed, and virologic results were determined. Patients’ homes were visited to determine the level of exposure to allergens.

Sensitization to allergens was higher in both groups with asthma. Sixty-six percent of patients with acute asthma were sensitized and exposed to allergens, compared with 37% of the outpatient group and 15.1% of the inpatient controls. Similarly, exposure to viruses was linked with asthma; virus was detected in 26.2% of the acute asthma group, 17.5% of the outpatient group, and 8.5% of inpatient controls.

When the various risk factors were examined independently, the combination of sensitization and exposure to high levels of allergens was associated with hospital admission; detection of virus alone was not. Of the 16 patients who had detectable viruses and were admitted to the hospital for asthma, 14 were sensitized and exposed to high levels of allergens. However, the addition of virus detection to the combination of sensitization and exposure to high levels of allergens raised the odds ratio for hospital admission from 2.3 to 8.4.

Allergens and viruses may act together to exacerbate asthma, and the authors conclude that in the absence of virus control, exposure to allergens should be reduced.

Green RM, Custovic A, Sanderson G, et al. Synergism between allergens and viruses and risk of hospital admission with asthma: case-control study. BMJ. 2002;324:763-766.

Health professionals often recommend over-the-counter (OTC) cough medicines for the treatment of acute cough. Evidence of these medicines’ effectiveness is not conclusive, however. Schroeder and Fahey conducted a review of published studies to determine whether OTC cough medicines are effective in treating cough in adults with upper respiratory tract infections.

Fifteen trials with a total of 2,166 patients were evaluated. The trials tested OTC cough suppressants, expectorants, and antihistamine/decongestant combinations. Outcomes included frequency and severity of cough and, in 10 trials, adverse effects.

The studies failed to demonstrate any consistent difference between treatment and control groups. In nine of 15 trials, active treatment was no more effective than placebo, and according to the investigators, the positive results in the remaining trials were of questionable relevance. The authors concluded that OTC cough medicines should not be recommended as a matter of course for cough associated with upper-respiratory-tract infections.

Schroeder K, Fahey T. Systematic review of randomised controlled trials of over the counter cough medicines for acute cough in adults. BMJ. 2002;324:329-331.

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