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ASSOCIATION BETWEEN BMI AND HEPATITIS C IN THE UNITED STATES
S Missiha, J Wang, EJ Heathcote, K Khan
BACKGROUND: Obesity complicates chronic hepatitis C (CHC) by accelerating fibrosis, worsening necroinflammatory scores, increasing the risk of hepatocellular carcinoma, and decreasing rates of response to current therapy. CHC has previously been associated with type II diabetes, a relationship possibly mediated by hepatitis C induced insulin resistance. A recent study in a major tertiary care center has suggested an independent correlation between CHC and obesity, but the finding may be subject to referral bias and requires validation.
OBJECTIVE: To determine the relationship between hepatitis C virus (HCV) and body mass index (BMI) in a large population-based cohort.
METHODS: Data from two time intervals of the National Health and Nutrition Examination Survey (NHANES), a cross-sectional stratified probability sample of the civilian non-institutionalized U.S. population, were retrospectively analyzed to identify factors associated with high BMI. Multivariate analysis using linear regression was conducted to control for demographic and lifestyle factors known to be associated with BMI measured as a continuous variable. The diagnosis of hepatitis C was established by positive serology.
RESULTS: The primary data set from 1999-2004 included 240 subjects who tested anti-HCV positive and 11,093 seronegative individuals, while in the secondary data set from an earlier study (1988-1994) there were 361 subjects who tested anti-HCV positive and 14,267 seronegative individuals. In the primary data set, hepatitis C positive serology was inversely correlated with high BMI (beta coefficient 1.64, p=0.0045) on multivariate analysis. Other independent predictors of high BMI include age 30 to 69 (p=0.0000), non-Hispanic black or Mexican American race (p=0.0000), US born birthplace (p=0.0176), grade 12 or less education (p=0.0008), non-current smoking status (p=0.0000), and low self-reported activity level (p=0.0264). No significant relationship was found with gender, poverty, alcohol use, or estimated daily energy consumption. In the secondary data set, anti-HCV positive status showed a trend toward lower BMI, but the result was not significant on multivariate analysis (p=0.1861). Other independent predictors were similar with the addition of male gender (p=0.0007) and low alcohol intake (p=0.207) being associated with high BMI.
CONCLUSION: Chronic hepatitis C appears to be associated with low BMI. The reasons for this warrant further study.