O were current cigarette smokers (176 patients) or former cigarette smokers (56 patients) with biopsies from patients who had never smoked cigarettes (77 patients). They found that current and former smokers had more inflammation and scarring of their livers than did nonsmokers. This finding could not be explained by other factors, such as concurrent alcohol use, that are known to aggravate the inflammation and scarring in hepatitis c. viagra online from canada no prescription The authors concluded that patients with chronic hepatitis c should be informed that smoking cigarettes could worsen their liver disease. Chronic hepatitis c can seriously damage the liver. Any study that suggests a way of lessening the damage is potentially important. viagra generic As always, however, the question must be asked, how well does the study support the conclusions? viagra forums uk How strong is the association between smoking cigarettes and greater liver damage? viagra without a doctor prescription As we have done several times in other articles, let's look critically at the study. viagra coupon printable The study was published in a first tier journal and authors are well-known and respected in the field of liver disease. However, the design of the study, referred to as an observational study, is not the strongest. In observational studies, observations are made--in this case, a history of smoking and examination of liver biopsies--and then associations are looked for among the observations. Although this is a good way of looking for relationships between observations, it is a weak method for determining cause and effect. viagra daily use mg For example, the authors suggest, on the basis of the association they found, that smoking cigarettes worsens the liver damage. The same association might also occur if patients with more severe liver disease are more likely to smoke! viagra canada online This study by itself provides limited support for an association between smoking and more severe liver damage. However, the authors cite several other studies in patients with chronic liver disease that show a similar association. viagra no prescription These other studies with similar findings add support to the conclusion of the hepatology study that there is an association between smoking cigarettes and liver damage. buy generic viagra online (the other studies also suggest that smoking cigarettes is associated with liver damage in chronic liver disease due to alcohol and hepatitis b. ) a type of study that offers the strongest support for a causal association between two observations is called an interventional study. For example, patients who havechronic hepatitis c on a liver biopsy could be randomly assigned to smoke or not smoke, and then additional biopsies could be examined at a later time. viagra samples If cigarettes are damaging, the biopsies from the smokers should be worse than the biopsies from the nonsmokers. For ethical reasons, such a study cannot be done. (it could be done. generic viagra cheap no prescription