Search

Background: Defining the primary characteristics of persons infected with hepatitis C virus (HCV) enables physicians to more easily identify persons who are most likely to benefit from testing for the disease. Objective: To describe the HCV-infected population in the United States. Design: Nationally representative household survey. Setting: U.S. civilian, noninstitutionalized population. Participants: 15 079 participants in the National Health and Nutrition Examination Survey between 1999 and 2002. Measurements: All participants provided medical histories, and those who were 20 to 59 years of age provided histories of drug use and sexual practices. Participants were tested for antibodies to HCV (anti-HCV) and HCV RNA, and their serum alanine aminotransferase (ALT) levels were measured. Results: The prevalence of anti-HCV in the United States was 1.6% (95% CI, 1.3% to 1.9%), equating to an estimated 4.1 million (CI, 3.4 million to 4.9 million) anti-HCV-positive persons nationwide; 1.3% or 3.2 million (CI, 2.7 million to 3.9 million) persons had chronic HCV infection. Peak prevalence of anti-HCV (4.3%) was observed among persons 40 to 49 years of age. A total of 48.4% of anti-HCV-positive persons between 20 and 59 years of age reported a history of injection drug use, the strongest risk factor for HCV infection. Of all persons reporting such a history, 83.3% had not used injection drugs for at least 1 year before the survey. Other significant risk factors included 20 or more lifetime sex partners and blood transfusion before 1992. Abnormal serum ALT levels were found in 58.7% of HCV RNA-positive persons. Three characteristics (abnormal serum ALT level, any history of injection drug use, and history of blood transfusion before 1992) identified 85.1% of HCV RNA-positive participants between 20 and 59 years of age. Limitations: Incarcerated and homeless persons were not included in the survey. Conclusions: 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.

The factors associated with tetanus and diphtheria immunity among the women in the United States is examined. The result indicates that obstetricians and gynecologists who are the medical providers for women should be familiar with the advisory community on immunization practices recommendations regarding diphtheria toxoid booster vaccines.

Background: Serologic data on diseases that are preventable by vaccine are useful to evaluate the success of immunization programs and to identify susceptible subgroups. Objective: To provide national estimates of immunity to diphtheria and tetanus by measurement of serum antibody levels. Design: Examination of data from the Third National Health and Nutrition Examination Survey, a representative cross-sectional sample of the U.S. population. Setting: 89 randomly selected locations throughout the United States. Participants: 18 045 persons 6 years of age of older who were examined from 1988 to 1994. Measurements: Serum samples obtained at a single time point were tested for diphtheria and tetanus antitoxin. Results: Overall, 60.5% of Americans 6 years of age or older had fully protective levels of diphtheria antibody (>=0.10 IU/mL) and 72.3% had protective levels of tetanus antibody (>0.15 IU/mL). Ninety-one percent of Americans 6 to 11 years of age had protective levels of both diphtheria and tetanus antibody; this proportion decreased to approximately 30% among persons 70 years of age (29.5% for diphtheria and 31.0% for tetanus). Adult Mexican-Americans were slightly less likely to have protective levels of antibody to both toxins. Only 47% of persons 20 years of age or older had levels that were protective against both diseases, and only 63% of adults who were protected against tetanus were also protected against diphtheria. Conclusions: A substantial proportion of adults in the United States do not have antibody levels that are protective against diphtheria and tetanus. In addition, although the recommended vaccine is a combination of tetanus and diphtheria, only 63% of adults with protective antibody to tetanus also had protective antibody to diphtheria.

Background: The prevalence of Chlamydia trachomatis genital infection in the United States population is unknown. Using a new urine test for C. trachomatis, we conducted a pilot survey as part of the National Health and Nutrition Examination Survey III (NHANES III). Goal: To determine whether the prevalence of chlamydial infection in a convenience sample of NHANES participants was high enough to justify testing for C. trachomatis in a national survey. Study Design: NHANES III, conducted from 1988 to 1994, was based on a stratified multistage probability sample of the United States population. Non-Hispanic blacks and Mexican-Americans were oversampled. Using the ligase chain reaction assay for C. trachomatis, we tested urine from participants 12 to 39 years of age from 10 of the 89 sites of NHANES III. The prevalence of infection was calculated by racial or ethnic group. Results: We tested 1,144 study participants, of whom 65% were female, 30% were non-Hispanic blacks, and 30% were Mexican-American. Prevalence was higher for non. Hispanic blacks (7%) than for Mexican-Americans (3%) and non-Hispanic whites (2%). Prevalence was higher for women than men in non-Hispanic blacks (7% vs. 6%), Mexican-Americans (5% vs. 2%), and non-Hispanic whites (2% vs. 1%). In 15- to 19-year-old women, prevalence was 13% in non-Hispanic blacks, 11% in Mexican-Americans, and 5% in non-Hispanic whites. Conclusion: The prevalence of C. trachomatis genital infection was high enough to suggest that a reliable national prevalence estimate could be obtained in a national probability sample survey., There appears to be enough Chlamydia trachomatis genital infections in the US to justify a national disease prevalence survey. Chlamydia can cause pelvic inflammatory disease, pain, and infertility in women. Researchers tested 1,144 people for the condition, and found that 7% of blacks, 3% of Mexican-Americans, and 2% of whites were infected. Women were consistently infected at higher rates than men, and the infection was most common among 15-19 year old women.

Data from the third National Health and Nutrition Examination Survey (NHANES III) indicate that about half a million US residents are infected with the AIDS virus. Of the 11,203 people in the survey tested for HIV, 59, or 0.32%, were HIV-positive. This translates to 461,000 people nationwide. However, the survey participants were between the ages of 18 and 59 and resided in households. Thus, the survey did not include homeless people, prisoners and others at high risk of infection.

African-Americans may be more likely to be HIV positive than whites, and men may be more likely than women to be infected. A portion of participants in a national health and nutrition survey provided blood samples that were tested anonymously for HIV antibodies. Among 5,430 adults between the ages of 18 and 59, 29 had positive tests. Analysis of the demographic data showed that African-Americans were 4.3 times more likely than whites and 2.7 times more likely than Mexican Americans to be HIV positive. Men were estimated to be three to four times as likely as women to be HIV positive. Most of the study participants who tested positive for HIV were in the younger age group, that is from 18 to 39. The prevalence estimates might be lower than actual prevalence if persons more likely to be HIV positive declined to participate in the study. Also, the survey covered only civilian persons living in households, excluding prisoners and homeless people.

Although infections of the genital tract by human papillomavirus (HPV) may be associated with genital warts, they are not clinically obvious in many cases and must be diagnosed by sophisticated laboratory assays. To learn more concerning the prevalence of HPV infection in an inner-city group of women who visited a clinic that treated sexually transmitted diseases (STDs), a study of 116 patients was carried out. The patients were interviewed and underwent gynecological examinations during which specimens were collected. Tests were carried out for several STDs in addition to HPV infection. A comparison of the results of different tests for diagnosing HPV was made. STDs were common among this clinic population: 14 percent of the patients tested positive for gonorrhea; 15 percent were infected with Chlamydia trachomatis (which causes chlamydia); 21 percent had signs of Trichomonas vaginalis (which causes trichomoniasis); and 23 percent had bacterial vaginosis. Between 12 percent and 41 percent of the women were infected with HPV; the results varied according to the diagnostic test used. Evaluation of Pap smears for pathologic changes associated with HPV led to the highest estimation of the prevalence of HPV, while diagnoses based on the presence of warts led to a much lower estimate. Each diagnostic approach has strengths and weaknesses, and almost one-fifth of the specimens could not be evaluated for HPV by all methods. The difficulty in obtaining appropriate specimens hinders the accurate diagnosis of the disease. Diagnosing HPV infection presents an important problem for STD clinics. (Consumer Summary produced by Reliance Medical Information, Inc.)

Research in sexually transmitted diseases (STD) has been primarily directed at biological and clinical aspects. Recently, the more common STDs have become more difficult to control and contain, and new STDs have appeared that are not responsive to the usual therapies. Alternative approaches are required for prevention. Behavior modification as one of these alternatives was shown to be successful in homosexual males in response to the AIDS epidemic. These behavioral changes have also resulted in reduced levels of syphilis and gonorrhea for this population. Changes in sexual habits, earlier onset of sexual activity in women, unplanned pregnancies, and problems of youth make the need for educational and behavioral interventions more urgent. Many of the high risk persons are users of inner city STD clinics and these clinics provide an important point for the dissemination of health and related information. A study group of 116 African-American women, 16 to 43 years old, were selected from those attending an inner city clinic. The patients were consecutively selected, and the usual routine tests were conducted as indicated by patient complaints and symptoms. Each woman was interviewed and questioned regarding sexual behavior, age at first intercourse, number of partners, frequency, pregnancies, sanitary product and douche usage, knowledge of the Pap test, social and smoking habits, and other general and sex related questions. Responses strongly indicated a lack of rudimentary information and the need for both clinical and social education. The STD clinic provides a suitable setting for the delivery of this information. (Consumer Summary produced by Reliance Medical Information, Inc.)

The prevalence of hepatitis B virus (HBV) infection was determined using sera from persons participating in the second National Health and Nutrition Examination Survey, conducted from 1976 to 1980. Of 14,488 scientifically selected participants aged 12 to 74, 821 had evidence of past or present infection with HBV. In the white population, the weighted estimate of hepatitis B infection was 3.2 percent (95 percent confidence interval, 3.1 to 4.2). A steady increase with age was seen; by ages 65 to 74, the prevalence was 6.9 percent (95 percent confidence interval, 5.2 to 8.5). In the black population, the overall weighted estimate of prevalence was 13.7 percent (95 percent confidence interval, 11.6 to 15.8). In this racial group, there was a dramatic increase with age, with the oldest age groups having a prevalence of 39.6 percent (95 percent confidence interval, 29.1 to 50.0). In both racial groups, there was a low prevalence of infection in young children that began to rise between ages 12 and 18. In a multivariate analysis of factors associated with infection, there was an interaction of race with age; therefore, the odds ratio for race is presented for four ages. This ratio ranged from 3.0 (95 percent confidence interval, 1.8 to 4.2) for a 15-year-old to 8.2 (95 percent confidence interval, 6.5 to 10.3) for a 70-year-old. These relative odds estimates were not substantially affected by adjustment for the available information on risk factors for HBV infection. The results of this study in a representative sample of the United States population show that adult black Americans are at high risk for hepatitis B infection. Other independent predictors of HBV positivity include male sex; residing in the South, Northeast, or West; residing in a city of 250,000 or more people; serving in the armed forces; living below the poverty level; and having a positive treponemal test for syphilis. These data suggest that the immunization practices for controlling this disease should be re-examined., From 1976 to 1980, the National Center for Health Statistics examined 20,322 people from a total representative sample of 27,802. Of these, sufficient volume of blood was obtained to measure hepatitis B markers in 14,488. Various risk factors were determined from the patient histories of those testing positive. The prevalence of hepatitis B infection in the white population was 3.2 percent, whereas it was 13.7 percent among blacks. Other significant risk factors included being male, living in the Northeast, South, or West, and living in a city of population greater than 250,000. Also included in the risk factors were service in the armed forces, living below poverty level, and testing positive for syphilis. Many of these risk factors are related to behavioral risk factors such as male homosexuality, intravenous drug use, and criminal behavior resulting in imprisonment. However, many potential vaccine recipients will deny belonging to one of these risk groups. The authors recommend, therefore, that vaccines be made available to all persons at risk based on the epidemiology rather than on the basis of self-reported high-risk behaviors. (Consumer Summary produced by Reliance Medical Information, Inc.)

Objectives. We described seroprevalence of antibody to hepatitis A virus (anti-HAV) in the United States during 1999–2006 and compared it with seroprevalence before the availability of vaccine.Methods. We analyzed data from the 1988–1994 and 1999–2006 National Health and Nutrition Examination Survey (NHANES) to obtain estimates of anti-HAV seroprevalence for the U.S. household population. We grouped region of residence based on the 1999 Advisory Committee on Immunization Practices recommendations into 17 states with any recommendation (vaccinating) and 33 states without any recommendation (non-vaccinating).Results. During 1999–2006, the overall seroprevalence of anti-HAV was 34.9% (95% confidence interval [CI] 33.1, 36.7). During 1999–2006, U.S.-born children living in vaccinating states (33.8%, 95% CI 26.2, 42.2) had a higher seroprevalence than children in non-vaccinating states (11.0%, 95% CI 9.4, 12.8; p<0.001). Seroprevalence among children increased from 8.0% (95% CI 6.3, 10.1) during 1988–1994 to 20.2% (95% CI 16.0, 24.8) during 1999–2006 (p<0.001). For U.S.-born children aged 6–19 years, the strongest factor associated with seroprevalence was residence in vaccinating states. Among U.S.-born adults aged >19 years, the overall age-adjusted seroprevalence of anti-HAV was 29.9% (95% CI 28.3, 31.5) during 1999–2006, which was not significantly different from the seroprevalence during 1988–1994 (32.2%, 95% CI 30.1, 34.4).Conclusions. Increases in seroprevalence among children in vaccinating states suggest a positive effect of the 1999 vaccination recommendations.

Objective. We estimated the varicella seroprevalence among the U.S. population aged 6–49 years based on retested National Health and Nutrition Examination Survey (NHANES) specimens collected between 1999 and 2004—originally tested using a method unsuitable for detecting vaccine-induced immunity—and compared it with historical estimates.Methods. We performed a confirmatory test suitable for detecting vaccine-induced immunity on all available specimens from 6- to 19-year-olds who originally tested negative (n=633), and on 297 randomly selected specimens that had tested positive. Retest results superseded original results for determining seroprevalence. We assessed seroprevalence for the entire sample aged 6–49 years (n=16,050) by participant demographic characteristics and compared it with historical estimates (NHANES 1988–1994).Results. The percentage of false-negative results for the original test was higher for specimens from younger children (6–11 years of age: 27.5%; 12–19 years of age: 13.3%) and for specimens collected most recently (2001–2004: 26.0%; 1999–2000: 12.6%). The age-adjusted rate of varicella seroprevalence for 1999–2004 was 93.6% for 6- to 19-year-olds and 98.0% for adults aged 20–49 years compared with 90.0% and 98.1%, respectively, for 1988–1994. We found an increase in seropositivity between the survey periods, from 93.2% to 97.2% (p<0.001) among 12- to 19-year-olds. For children, non-Hispanic black ethnicity and younger age were associated with lower seroprevalence in both survey periods.Conclusions. Varicella seroprevalence increased with age among children and was uniformly high in the U.S. adult population between 1999 and 2004. The original testing produced false-negative seroprevalence results among children's specimens collected between 1999 and 2004 from 6- to 19-year-olds.

Purpose: The study determines the consent rates for storage of biologic samples for future research with and without genetic studies and describes trends in sociodemographic factors associated with consent.Methods: We performed an analysis of the characteristics of consenting individuals participating in three data cycles of the National Health and Nutrition Examination Survey, a nationally representative survey of the U.S. population.Results: In the 1999 to 2000 and the 2001 and 2002 surveys, 84.8% and 90.1% of eligible participants, respectively, consented to have their biologic samples including DNA stored in a national repository. Female and non-Hispanic black participants were least likely to consent when genetic studies and DNA were included. In the 2003 to 2004 survey, with the discontinuation of the DNA collection, 98.4% signed the consent document and these race/gender differences were no longer observed.Conclusion: Females and non-Hispanic blacks consistently had lower consent rates during the survey years when genetic studies were mentioned in the consent, but once DNA collection was discontinued these differences disappeared. These findings demonstrate wide acceptance among survey participants for allowing storage of specimens for future studies but indicate the need to explore race/gender issues with the collection and storage of DNA for genetic research.

Purpose: To determine the sociodemographic factors associated with consent for storage of DNA for future genetic research.Methods: Analysis of the characteristics of consenting individuals participating in the National Health and Nutrition Examination Survey, a nationally representative survey of the US household population.Results: In 1999, 84% (95% confidence interval 82.4–85.6) of eligible participants consented to have their blood samples included in a national repository for genetic research. In 2000, 85.3% (95% confidence interval 84.0–86.6) consented. Females and black participants in both years were least likely to consent (1999, 82.2% and 73.2%; 2000, 83.6% and 81.3%, respectively). An assessment by logistic regression demonstrated that in both years only non-Hispanic black race/ethnicity was a significant independent predictor for not consenting to future genetic research.Conclusion: Although non-Hispanic black individuals have overall response rates similar to those of the other racial/ethnic groups, they are less likely to agree to have a blood sample saved for future genetic research. In balance, however, these findings demonstrate wide acceptance among survey participants for allowing storage of specimens for future genetic research across many demographic variables.

At the time of varicella vaccine introduction in the United States, an estimated 4 million episodes of varicella occurred annually. This survey of varicella seroprevalence is the first to describe immunity to a vaccine‐preventable disease prior to vaccine introduction in the United States population. The objective of this analysis is to describe patterns of naturally‐acquired varicella and understand characteristics associated with infection in the varicella vaccine–naive United States population. A nationally representative cross‐sectional health examination survey that included venipuncture was conducted among 21,288 U.S. participants aged 6 years and older from 1988 through 1994. Serologic evidence of varicella‐zoster virus infection was measured by enzyme immunoassay of varicella‐zoster virus‐specific IgG antibody. The seroprevalence of IgG antibody to varicella‐zoster virus increased from 86.0% in children aged 6 through 11 years to 99.6% in adults aged 40 through 49 years. Immunity to varicella remained at 99% or higher in Americans aged 50 years and older. Among persons aged 6 through 19 years, non‐Hispanic black children were 40% less likely to be seropositive compared with white children (odds ratio [OR], 0.6; 95% confidence interval [CI], 0.4–0.8). Among young adults aged 20 through 39 years, women with a history of live birth (OR, 4.3; 95% CI, 2.1–8.7) and married men (OR, 2.7; 95% CI, 1.2–5.7) were more likely to have naturally‐acquired immunity to varicella. This study found that, prior to use of varicella vaccine in the United States, age, race, and marital characteristics were independently associated with naturally acquired varicella. Future varicella serosurveys in Americans will provide essential information to interpret the population impact of varicella vaccine. J. Med. Virol. 70:S111–S118, 2003. © 2003 Wiley‐Liss, Inc.

The design of the laboratory component of a mobile examination survey such as the National Health and Nutrition Examination Survey requires that the physical limitation of the mobile examination center be balanced against the requirements of the laboratory analyses needed to fulfill the goals of the survey. In order to include an analysis in the survey, the scientific merit of the laboratory test must be established and a consensus must be reached on the appropriateness of the technology for the six years of the survey. The public health importance of the analysis and the subsequent results are also evaluated before inclusion into the laboratory protocol. Finally, the feasibility of incorporating the analysis into the protocol is reviewed. The laboratory component of NHANES III is discussed, addressing these points with descriptions of the reasons for inclusion and exclusion of key analytes.

Precise estimates of the incidence of hepatitis B virus (HBV) infection are required to assess the impact of immunization and other prevention strategies in the United States. Race- and age-specific prevalence data obtained from the second and third National Health and Nutrition Examination Surveys (NHANES II, 1976–1980, and NHANES III, 1988–1994) were used to estimate the annual incidence of HBV infection by catalytic modeling. During the period covered by NHANES II, an estimated 323,462 persons were infected annually, and 334,863 were infected annually during the period covered by NHANES III. No statistically significant declines in prevalence of HBV infection occurred between the two surveys, a period during which hepatitis B vaccination targeted only limited numbers of high-risk adults.

To provide more accurate estimates of Helicobacter pylori infection in the US population, IgGantibody levels were measured in serum from 2581 persons aged 6–19 years examined during phase1 of the third National Health and Nutrition Examination Survey. Overall, 24.8% of participantshad evidence of H. pylori infection. Infection was strongly associated with increasing age (X2trend, P < .01) and being nonwhite (17.0% of non-Hispanic whites vs. 40.1% of non-Hispanic blacks and 42.0% of Mexican Americans infected). In a multivariate logistic regression model, H. pylori infection was significantly associated with increasing age (odds ratio [OR] = 1.07/year), being nonwhite (non-Hispanic black OR = 2.6 or Mexican American OR = 1.8), poverty (OR = 1.5), crowding (OR = 5.6), and- head of household education level (OR = 1.8). In Mexican Americans, infection was associated with birth outside the United States or Canada in the univariate analyses but was not significantly associated after adjustment for age, poverty, crowding, and head of household education level.