Many Americans are infected with HCV. Most were born between 1945 and 1964 and can be identified with current screening criteria. History of injection drug use is the strongest risk factor for infection.

Higher BMI is associated with higher CRP concentrations, even among young adults aged 17 to 39 years. These findings suggest a state of low-grade systemic inflammation in overweight and obese persons.

One concern is to what extent the subset of NHANES participants evaluated for HCV infection and diabetes was representative of the entire NHANES population sample. This is a significant question because the overall NHANES sample is considered the best representation of the general population of the United States, a collection of subjects free of the bias usually present in clinic-based investigations. Thus, it was reassuring that the subset of NHANES that could be evaluated for HCV infection and diabetes was both large (9,841 persons) and similar to other NHANES members with respect to many factors, including all recognized correlates of both HCV infection and diabetes. 1 This representation essentially eliminates the potential for selection bias. Another strength of the NHANES analysis is the careful testing for HCV infection performed by the Hepatitis Branch at the Centers for Disease Control and Prevention. Because HCV infection was assessed by second-generation enzyme immunoassay and confirmed by supplemental antibody testing, there is no doubt that most positive results reflect true HCV exposure. Indeed, in the subset tested for both HCV antibody and RNA, HCV RNA was detected in all but 26%, the percent one would expect to have cleared infection if all antibody-positive subjects had been previously infected. 3 Dr. Everhart raised the question of whether the antibody testing should be the main determinant of HCV or if the analysis should be restricted to persons with both HCV antibody and RNA. 2 If one were convinced that the association exists exclusively because ongoing HCV infection caused diabetes, it would have been appropriate to restrict the analysis to persons whose blood contained both HCV antibodies and RNA. Because too little is known about the pathogenesis and temporal sequence of HCV infection and diabetes to make these assumptions, the analysis initially was presented using antibody testing as the marker of HCV exposure. Nonetheless, Dr. Nainan and coworkers at the Centers for Disease Control and Prevention generously provided the HCV RNA data. For the subset for whom there is HCV RNA testing, the age-adjusted odds of type 2 diabetes in persons with HCV RNA and antibody was 2.48 (95% CI 1.23-5.01) compared with 0.98 for persons with HCV antibody but not RNA. If confirmed , these data are not consistent with the conjecture that diabetes leads to HCV infection, but instead favor hypotheses suggesting that persistent HCV infection is associated with the subsequent development of diabetes. Another important discovery in the analysis of HCV infection and type 2 diabetes in NHANES was the difference in the magnitude and direction of the association in persons of relatively young ages. Type 2 diabetes is a clinically heterogeneous syndrome that, according to the Cecil Textbook of Medicine, "typically appears after the age of 40 years." 4 In NHANES III, type 2 diabetes was not associated with HCV infection in persons less than 40 years of age. 1 Type 2 diabetes may be a different condition when it mani...

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These data show declines in HSV-2 seroprevalence, suggesting that the trajectory of increasing HSV-2 seroprevalence in the United States has been reversed. Seroprevalence of HSV-1 decreased but the incidence of genital herpes caused by HSV-1 may be increasing.

Background Knowledge of the number of persons with chronic hepatitis C virus (HCV) infection in the United States is critical for public health and policy planning. Objective To estimate the prevalence of chronic HCV infection between 2003 and 2010 and to identify factors associated with this condition. Design Nationally representative household survey. Setting U.S. noninstitutionalized civilian population. Participants 30 074 NHANES (National Health and Nutrition Examination Survey) participants between 2003 and 2010. Measurements Interviews to ascertain demographic characteristics and possible risks and exposures for HCV infection. Serum samples from participants aged 6 years or older were tested for antibody to HCV; if results were positive or indeterminate, the samples were tested for HCV RNA, which indicates current chronic infection. Results Based on 273 participants who tested positive for HCV RNA, the estimated prevalence of HCV infection was 1.0% (95% CI, 0.8% to 1.2%), corresponding to 2.7 million chronically infected persons (CI, 2.2 to 3.2 million persons) in the U.S. noninstitutionalized civilian population. Infected persons were more likely to be aged 40 to 59 years, male, and non-Hispanic black and to have less education and lower family income. Factors significantly associated with chronic HCV infection were illicit drug use (including injection drugs) and receipt of a blood transfusion before 1992; 49% of persons with HCV infection did not report either risk factor. Limitation Incarcerated and homeless persons were not surveyed. Conclusion This analysis estimated that approximately 2.7 million U.S. residents in the population sampled by NHANES have chronic HCV infection, about 500 000 fewer than estimated in a similar analysis between 1999 and 2002. These data underscore the urgency of identifying the millions of persons who remain infected and linking them to appropriate care and treatment. Primary Funding Source None.

Nasal colonization with MRSA has increased in the United States, despite an overall decrease in nasal colonization with S. aureus. PFGE types associated with community transmission only partially account for the increase in MRSA colonization.

Many persons in the United States are colonized with S. aureus; prevalence rates differ demographically. MRSA colonization prevalence, although low nationally in 2001-2002, may vary with demographic and organism characteristics.