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September 17, 2003

Risks of Smallpox Vaccination

Author Affiliations

Letters Section Editor: Stephen J. Lurie, MD, PhD, Senior Editor.

JAMA. 2003;290(11):1452. doi:10.1001/jama.290.11.1452-a

In Reply: In response to Dr Kashyap and colleagues and Drs Schattner and Knobler, several retrospective studies have examined the possible association of HCV and diabetes mellitus.1-4 Some have found a strong association and others have not. It is important to note that HCV may be a marker for an associated factor that predisposes to diabetes mellitus. For example, cirrhosis in general is associated with insulin resistance and diabetes.5 Thus, a diagnosis of diabetes in a patient with cirrhosis secondary to HCV may be related to the presence of cirrhosis and not HCV. Furthermore, obesity is associated with diabetes and may also hasten progression of liver disease secondary to HCV.6 Obese patients with diabetes (and HCV) may present more frequently for medical evaluation and thus lead to an apparent increased prevalence of diabetes in the HCV population. Few studies that have sought an association between HCV and diabetes have been controlled for severity of liver disease and body mass index. Schattner and Knobler mention that more adverse hepatic histology and increased body mass index may be associated with an increased risk of diabetes in patients with chronic HCV. Although a direct association between HCV and diabetes is posible, it remains unproven.