Estimating the Prevalence of Injection Drug Users in the U.S. and in Large U.S. Metropolitan Areas from 1992 to 2002

This paper estimates the prevalence of current injection drug users (IDUs) in 96 large U.S. metropolitan statistical areas (MSAs) annually from 1992 to 2002. Multiplier/allocation methods were used to estimate the prevalence of injectors because confidentiality restrictions precluded the use of other commonly used estimation methods, such as capture-recapture. We first estimated the number of IDUs in the U.S. each year from 1992 to 2002 and then apportioned these estimates to MSAs using multiplier methods. Four different types of data indicating drug injection were used to allocate national annual totals to MSAs, creating four distinct series of estimates of the number of injectors in each MSA. Each series was smoothed over time; and the mean value of the four component estimates was taken as the best estimate of IDUs for that MSA and year (with the range of component estimates indicating the degree of uncertainty in the estimates). Annual cross-sectional correlations of the MSA-level IDU estimates with measures of unemployment, hepatitis C mortality prevalence, and poisoning mortality prevalence were used to validate our estimates. MSA-level IDU estimates correlated moderately well with validators, demonstrating adequate convergence validity. Overall, the number of IDUs per 10,000 persons aged 15-64 years varied from 30 to 348 across MSAs (mean 126.9, standard deviation 65.3, median 106.6, interquartile range 78-162) in 1992 and from 37 to 336 across MSAs (mean 110.6, standard deviation 57.7, median 96.1, interquartile range 67-134) in 2002. A multilevel model showed that overall, across the 96 MSAs, the number of injectors declined each year until 2000, after which the IDU prevalence began to increase. Despite the variation in component estimates and methodological and component data set limitations, these local IDU prevalence estimates may be used to assess: (1) predictors of change in IDU prevalence; (2) differing IDU trends between localities; (3) the adequacy of service delivery to IDUs; and (4) infectious disease dynamics among IDUs across time.     

HIV Prevalence Rates among Injection Drug Users in 96 Large US Metropolitan Areas, 1992–2002

This research presents estimates of HIV prevalence rates among injection drug users (IDUs) in large US metropolitan statistical areas (MSAs) during 1992–2002. Trend data on HIV prevalence rates in geographic areas over time are important for research on determinants of changes in HIV among IDUs. Such data also provide a foundation for the design and implementation of structural interventions for preventing the spread of HIV among IDUs. Our estimates of HIV prevalence rates among IDUs in 96 US MSAs during 1992–2002 are derived from four independent sets of data: (1) research-based HIV prevalence rate estimates; (2) Centers for Disease Control and Prevention Voluntary HIV Counseling and Testing data (CDC CTS); (3) data on the number of people living with AIDS compiled by the CDC (PLWAs); and (4) estimates of HIV prevalence in the US. From these, we calculated two independent sets of estimates: (1) calculating CTS-based Method (CBM) using regression adjustments to CDC CTS; and (2) calculating the PLWA-based Method (PBM) by taking the ratio of the number of injectors living with HIV to the numbers of injectors living in the MSA. We take the mean of CBM and PBM to calculate over all HIV prevalence rates for 1992–2002. We evaluated trends in IDU HIV prevalence rates by calculating estimated annual percentage changes (EAPCs) for each MSA. During 1992–2002, HIV prevalence rates declined in 85 (88.5%) of the 96 MSAs, with EAPCs ranging from −12.9% to −2.1% (mean EAPC = −6.5%; p < 0.01). Across the 96 MSAs, collectively, the annual mean HIV prevalence rate declined from 11.2% in 1992 to 6.2 in 2002 (EAPC, −6.4%; p < 0.01). Similarly, the median HIV prevalence rate declined from 8.1% to 4.4% (EAPC, −6.5%; p < 0.01). The maximum HIV prevalence rate across the 11 years declined from 43.5% to 22.8% (EAPC, −6.7%; p < 0.01). Declining HIV prevalence rates may reflect high continuing mortality among infected IDUs, as well as primary HIV prevention for non-infected IDUs and self-protection efforts by them. These results warrant further research into the population dynamics of disease progression, access to health services, and the effects of HIV prevention interventions for IDUs. Electronic supplementary material   The online version of this article doi: contains supplementary material, which is available to authorized users.

Estimating the Prevalence of Injection Drug Use among Black and White Adults in Large U.S. Metropolitan Areas over Time (1992–2002): Estimation Methods and Prevalence Trends

No adequate data exist on patterns of injection drug use (IDU) prevalence over time within racial/ethnic groups in U.S. geographic areas. The absence of such prevalence data limits our understanding of the causes and consequences of IDU and hampers planning efforts for IDU-related interventions. Here, we (1) describe a method of estimating IDU prevalence among non-Hispanic Black and non-Hispanic White adult residents of 95 large U.S. metropolitan statistical areas (MSAs) annually over an 11-year period (1992–2002); (2) validate the resulting prevalence estimates; and (3) document temporal trends in these prevalence estimates. IDU prevalence estimates for Black adults were calculated in several steps: we (1) created estimates of the proportion of injectors who were Black in each MSA and year by analyzing databases documenting injectors’ encounters with the healthcare system; (2) multiplied the resulting proportions by previously calculated estimates of the total number of injectors in each MSA and year (Brady et al., 2008); (3) divided the result by the number of Black adults living in each MSA each year; and (4) validated the resulting estimates by correlating them cross-sectionally with theoretically related constructs (Black- and White-specific prevalences of drug-related mortality and of mortality from hepatitis C). We used parallel methods to estimate and validate White IDU prevalence. We analyzed trends in the resulting racial/ethnic-specific IDU prevalence estimates using measures of central tendency and hierarchical linear models (HLM). Black IDU prevalence declined from a median of 279 injectors per 10,000 adults in 1992 to 156 injectors per 10,000 adults in 2002. IDU prevalence for White adults remained relatively flat over time (median values ranged between 86 and 97 injectors per 10,000 adults). HLM analyses described similar trends and suggest that declines in Black IDU prevalence decelerated over time. Both sets of IDU estimates correlated cross-sectionally adequately with validators, suggesting that they have acceptable convergent validity (range for Black IDU prevalence validation: 0.27 < r < 0.61; range for White IDU prevalence: 0.38 < r < 0.80). These data give insight, for the first time, into IDU prevalence trends among Black adults and White adults in large U.S. MSAs. The decline seen here for Black adults may partially explain recent reductions in newly reported cases of IDU-related HIV evident in surveillance data on this population. Declining Black IDU prevalence may have been produced by (1) high AIDS-related mortality rates among Black injectors in the 1990s, rates lowered by the advent of HAART; (2) reduced IDU incidence among Black drug users; and/or (3) MSA-level social processes (e.g., diminishing residential segregation). The stability of IDU prevalence among White adults between 1992 and 2002 may be a function of lower AIDS-related mortality rates in this population; relative stability (and perhaps increases in some MSAs) in initiating IDU among White drug users; and social processes. Future research should investigate the extent to which these racial/ethnic-specific IDU prevalence trends (1) explain, and are explained by, recent trends in IDU-related health outcomes, and (2) are determined by MSA-level social processes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Differing HIV Risks and Prevention Needs among Men and Women Injection Drug Users (IDU) in the District of Columbia

Washington, DC has among the highest HIV/AIDS rates in the US. Gender differences among injection drug users (IDUs) may be associated with adoption of prevention opportunities including needle exchange programs, HIV testing, psychosocial support, and prevention programming. National HIV Behavioral Surveillance data on current IDUs aged ≥18 were collected from 8/09 to 11/09 via respondent-driven sampling in Washington, DC. HIV status was assessed using oral OraQuick with Western Blot confirmation. Weighted estimates were derived using RDSAT. Stata was used to characterize the sample and differences between male and female IDU, using uni-, bi-, and multivariable methods. Factors associated with HIV risk differed between men and women. Men were more likely than women to have had a history of incarceration (86.6 % vs. 66.8 %, p < 0.01). Women were more likely than men to have depressive symptoms (73.9 % vs. 47.4 %, p < 0.01), to have been physically or emotionally abused (66.1 % vs. 16.1 %, p < 0.0001), to report childhood sexual abuse (42.7 % vs. 4.7 %, p < 0.0001), and pressured or forced to have sex (62.8 % vs. 4.0 %, p < 0.0001); each of these differences was significant in the multivariable analysis. Despite a decreasing HIV/AIDS epidemic among IDU, there remain significant gender differences with women experiencing multiple threats to psychosocial health, which may in turn affect HIV testing, access, care, and drug use. Diverging needs by gender are critical to consider when implementing HIV prevention strategies.     

The Geography of Recreational Open Space: Influence of Neighborhood Racial Composition and Neighborhood Poverty

The geography of recreational open space might be inequitable in terms of minority neighborhood racial/ethnic composition and neighborhood poverty, perhaps due in part to residential segregation. This study evaluated the association between minority neighborhood racial/ethnic composition, neighborhood poverty, and recreational open space in Boston, Massachusetts (US). Across Boston census tracts, we computed percent non-Hispanic Black, percent Hispanic, and percent families in poverty as well as recreational open space density. We evaluated spatial autocorrelation in study variables and in the ordinary least squares (OLS) regression residuals via the Global Moran’s I. We then computed Spearman correlations between the census tract socio-demographic characteristics and recreational open space density, including correlations adjusted for spatial autocorrelation. After this, we computed OLS regressions or spatial regressions as appropriate. Significant positive spatial autocorrelation was found for neighborhood socio-demographic characteristics (all p value = 0.001). We found marginally significant positive spatial autocorrelation in recreational open space (Global Moran’s I = 0.082; p value = 0.053). However, we found no spatial autocorrelation in the OLS regression residuals, which indicated that spatial models were not appropriate. There was a negative correlation between census tract percent non-Hispanic Black and recreational open space density (r_S = −0.22; conventional p value = 0.005; spatially adjusted p value = 0.019) as well as a negative correlation between predominantly non-Hispanic Black census tracts (>60 % non-Hispanic Black in a census tract) and recreational open space density (r_S = −0.23; conventional p value = 0.003; spatially adjusted p value = 0.007). In bivariate and multivariate OLS models, percent non-Hispanic Black in a census tract and predominantly Black census tracts were associated with decreased density of recreational open space (p value < 0.001). Consistent with several previous studies in other geographic locales, we found that Black neighborhoods in Boston were less likely to have recreational open spaces, indicating the need for policy interventions promoting equitable access. Such interventions may contribute to reductions and disparities in obesity.     

HCV Infection Prevalence Lower Than Expected among 18–40-Year-Old Injection Drug Users in San Diego, CA

San Diego, California shares the world’s busiest land border crossing with Tijuana, Mexico—a city where 95 % of injection drug users (IDUs) test hepatitis C virus (HCV) antibody-positive. Yet, little is known about the prevalence and risk behaviors for HCV among IDUs in San Diego. In 2009–2010, 18–40-year-old IDUs in San Diego County completed a risk assessment interview and serologic testing for HCV and HIV infection. Recruitment involved respondent-driven sampling, venue-based sampling at a syringe exchange program, and convenience sampling. Correlates of HCV infection were identified by multivariable logistic regression. Among 510 current IDUs, 26.9 % (95 % CI 23.0–30.7 %) and 4.2 % (95 % CI 2.4–5.9 %) had been infected with HCV and HIV, respectively. Overall, median age was 28 years; 74 % were male; 60 % white and 29 % Hispanic; and 96 % were born in the U.S. Median years of injecting was 6; 41 % injected daily; 60 % injected heroin most often; 49 % receptively shared syringes and 68 % shared other injection paraphernalia; and only 22 % reported always using new syringes in the past 3 months. Two thirds had ever traveled to Mexico and 19 % injected in Mexico. HCV infection was independently associated with sharing injection paraphernalia (adjusted odds ratio [AOR] = 1.69) and SEP use (AOR = 2.17) in the previous 3 months, lifetime history of drug overdose (AOR = 2.66), and increased years of injecting (AOR = 2.82, all P values <0.05). Controlling for recruitment method did not alter results. HCV infection prevalence among IDUs in San Diego was modest compared to other US cities and much lower than Tijuana. Given that known individual-level HCV risk factors were common in San Diego, the city’s lower HCV prevalence might be due to differences in social and structural factors between the cities.     

Erratum to: The Prevalence of HIV, HBV, HCV, and HIV-Related Risk-Taking Behaviors among Palestinian Injecting Drug Users in the East Jerusalem Governorate

The objective of the study was to determine HIV, HBV, HCV seroprevalence and to assess HIV risks among Palestinian injecting drug users (IDUs) in the East Jerusalem Governorate. Following formative research, a bio-behavioral survey using respondent-driven sampling was carried out in 2010 among 199 IDUs aged 19-56 years (M = 41.33, SD = 8.09). Venous blood was drawn for biological testing. Data on drug abuse and sexual behaviors were collected by face-to-face interviewing. No HIV + cases were found. Five participants were infected with Hepatitis B and 84 participants (estimated population proportion of 40.3 %) tested positive for Hepatitis C. A great majority of the surveyed IDUs (90.4 %) reported using sterile injecting equipment the last time they injected. In a multivariate assessment, age (OR = 2.52, p < .05), education (OR = 6.67, p < .01), personal network size (OR = .18, p < .001), and the frequency of drug injecting in the past month (OR = .20, p < .001) were associated with using sterile injecting equipment in the past week. Condom use at most recent sexual intercourse was reported by about a third (34.2 %) of IDUs. The study documented substantial exposure to HIV risks among Palestinian IDUs whose vulnerability is inseparable from sociopolitic and socioeconomic characteristics of their social environment.     

Prevalence of Children with Special Health Care Needs in Metropolitan and Micropolitan Statistical Areas in the United States

Objectives We estimate the prevalence of children with special health care needs (CSHCN) in 70 metropolitan and four micropolitan statistical areas across the United States. Methods The data are from the 2001 National Survey of CSHCN, which was sponsored by the Maternal and Child Health Bureau and conducted by the National Center for Health Statistics. Prevalence estimates were generated for 74 metropolitan and micropolitan statistical areas (M/MSAs) and 45 individual counties that were represented by at least 1,000 children in the sample. To generate the estimates, the child-level sample weights (representative at the national and state level) were recalibrated within each M/MSA and county to match Census 2000 counts of the child population by age, sex, and Hispanic ethnicity. Results M/MSA-level and county-level prevalence of CSHCN are compared with national- and state-level prevalence, and within M/MSAs and counties, prevalence is reported by age, sex and race/ethnicity. Most, but not all, M/MSA- or county-level prevalence estimates did not differ significantly from state-level estimates. Some M/MSAs and counties that did not differ from their states in overall prevalence of CSHCN did show some differences in prevalence for certain demographic subgroups. Conclusions Metropolitan health departments and Maternal and Child Health agencies that serve urban areas may find these new small area estimates useful for program planning purposes. This study demonstrates the importance of assessing whether state estimates may approximate local area estimates of the prevalence of CSHCN.     

Use of fake identification to purchase alcohol amongst 15-16 year olds: a cross-sectional survey examining alcohol access,consumption and harm

Objectives

Injection drug users (IDUs) are at high risk for HIV, hepatitis, overdose and other harms. Greater drug treatment availability has been shown to reduce these harms among IDUs. Yet, little is known about changes in drug treatment availability for IDUs in the U.S. This paper investigates change in drug treatment coverage for IDUs in 90 metropolitan statistical areas (MSAs) during 1993-2002.

Methods

We define treatment coverage as the percent of IDUs who are in treatment. The number of IDUs in drug treatment is calculated from treatment entry data and treatment census data acquired from the Substance Abuse and Mental Health Service Administration, divided by our estimated number of IDUs in each MSA.

Results

Treatment coverage was low in 1993 (mean 6.7%; median 6.0%) and only increased to a mean of 8.3% and median of 8.0% coverage in 2002.

Conclusions

Although some MSAs experienced increases in treatment coverage over time, overall levels of coverage were low. The persistence of low drug treatment coverage for IDUs represents a failure by the U.S. health care system to prevent avoidable harms and unnecessary deaths in this population. Policy makers should expand drug treatment for IDUs to reduce blood-borne infections and community harms associated with untreated injection drug use.     

Injecting Risk Behavior among Traveling Young Injection Drug Users: Travel Partner and City Characteristics

Young injection drug users (IDUs), a highly mobile population, engage in high levels of injecting risk behavior, yet little is understood about how such risk behavior may vary by the characteristics of the cities to which they travel, including the existence of a syringe exchange program (SEP), as well as travel partner characteristics. In 2004–2005, we conducted a 6-month prospective study to investigate the risk behavior of 89 young IDUs as they traveled, with detailed information gathered about 350 city visits. In multivariable analyses, travel to larger urban cities with a population of 500,000–1,000,000 was significantly associated with injecting drugs (adjusted odds ratio (AOR) = 3.71; 95 % confidence interval (CI), 1.56–8.82), ancillary equipment sharing (AES; AOR = 7.05; 95 % CI, 2.25–22.06) and receptive needle sharing (RNS; AOR = 5.73; 95 % CI, 1.11–27.95), as compared with visits to smaller cities with populations below 50,000. Region of the country, and the existence of a SEP within the city visited, were not independently associated with injecting drugs, AES, or RNS during city visits. Traveling with more than one injecting partner was associated with injecting drugs during city visits (AOR = 2.77; 95 % CI, 1.46–5.27), when compared with traveling alone. Additionally, both non-daily and daily/almost daily alcohol use during city visits were associated with AES (AOR = 3.37; 95 % CI, 1.42–7.68; AOR = 3.03; 95 % CI, 1.32–6.97, respectively) as compared with no alcohol consumption. Traveling young IDUs are more likely to inject when traveling with other IDUs and to engage in higher risk injection behavior when they are in large cities. Risk behavior occurring in city visits, including equipment sharing and alcohol consumption, suggests further need for focused interventions to reduce risk for viral infection among this population.     

Racial Segregation,Income Inequality,and Mortality in US Metropolitan Areas

Evidence of the association between income inequality and mortality has been mixed. Studies indicate that growing income inequalities reflect inequalities between, rather than within, racial groups. Racial segregation may play a role. We examine the role of racial segregation on the relationship between income inequality and mortality in a cross-section of US metropolitan areas. Metropolitan areas were included if they had a population of at least 100,000 and were at least 10% black (N = 107). Deaths for the time period 1991–1999 were used to calculate age-adjusted all-cause mortality rates for each metropolitan statistical area (MSA) using direct age-adjustment techniques. Multivariate least squares regression was used to examine associations for the total sample and for blacks and whites separately. Income inequality was associated with lower mortality rates among whites and higher mortality rates among blacks. There was a significant interaction between income inequality and racial segregation. A significant graded inverse income inequality/mortality association was found for MSAs with higher versus lower levels of black–white racial segregation. Effects were stronger among whites than among blacks. A positive income inequality/mortality association was found in MSAs with higher versus lower levels of Hispanic–white segregation. Uncertainty regarding the income inequality/mortality association found in previous studies may be related to the omission of important variables such as racial segregation that modify associations differently between groups. Research is needed to further elucidate the risk and protective effects of racial segregation across groups.     

Modelling the impact of prison vaccination on hepatitis B transmission within the injecting drug user population of England and Wales

A vaccination programme offering hepatitis B (HBV) vaccine at reception into prison has been introduced into selected prisons in England and Wales. The work here considers the impact of prison vaccination on the incidence and prevalence of hepatitis B virus (HBV) in the injecting drug user (IDU) population of England and Wales. A dynamic model of the transmission of HBV in IDUs is developed with key model assumptions and parameters being subject to sensitivity analyses. The base case model (that assumes that the vaccination coverage on prison reception is 5% in 2002, 10% in 2003 and then increases linearly up to 50% of prison receptions being vaccinated by 2006) predicts that the incidence of HBV in IDUs might be reduced by almost 80% in 12 years, and the HBV prevalence (IDUs ever infected by HBV) may be reduced from approximately 18% in 2002 to 7% in 2015. The model presented here demonstrates that HBV vaccination on prison reception can have a significant impact on the prevalence and incidence of HBV in the IDU population over time.     

HIV/AIDS among men who have sex with men and inject drugs--United States, 1985-1998

Men who have sex with men and inject drugs (MSM/IDU) pose unique challenges for human immunodeficiency virus (HIV) risk reduction efforts because they have multiple risks for HIV acquisition and transmission. This report presents 1) the demographic characteristics of MSM/IDU diagnosed with acquired immunodeficiency syndrome (AIDS) in 1998 and MSM/IDU living with AIDS as of December 31, 1998; 2) trends in AIDS incidence among MSM/IDU from 1985 to 1998; and 3) information on selected behaviors from interviews of MSM/IDU who had AIDS diagnosed from 1996 to 1998 in 12 states. The findings indicate that 1) over half of MSM/IDU with AIDS were non-Hispanic blacks and Hispanics, and most MSM/IDU with AIDS were reported from large metropolitan statistical areas (MSAs); 2) AIDS incidence has declined since 1996; and 3) a high prevalence of drug-related and sexual risk behaviors occurred among MSM/IDU with AIDS.     

Developing an HIV behavioral surveillance system for injecting drug users: the National HIV Behavioral Surveillance System

While disease surveillance for HIV/AIDS is now widely conducted in the United States, effective HIV prevention programs rely primarily on changing behavior; therefore, behavioral data are needed to inform these programs. To achieve the goal of reducing HIV infections in the U.S., the Centers for Disease Control and Prevention, in cooperation with state and local health departments, implemented the National HIV Behavioral Surveillance System (NHBS) for injecting drug users (IDUs) in 25 selected metropolitan statistical areas (MSAs) throughout the United States in 2005. The surveillance system used respondent-driven sampling (RDS), a modified chain-referral method, to recruit IDUs for a survey measuring HIV-associated drug use and sexual risk behavior. RDS can produce population estimates for specific risk behaviors and demographic characteristics. Formative assessment activities-primarily the collection of qualitative data-provided information to better understand the IDU population and implement the surveillance activities in each city. This is the first behavioral surveillance system of its kind in the U.S. that will provide local and national data on risk for HIV and other blood-borne and sexually transmitted infections among IDUs for monitoring changes in the epidemic and prevention programs.     

Predictors of Never Being Screened for Cervical Cancer by Metropolitan Area

Previous studies have shown an association between cervical cancer screening and racial/ethnic minority status, no usual source of care, and lower socioeconomic status. This study describes the demographics and health beliefs of women who report never being screened for cervical cancer by area of residence. Data from the 2010 Behavioral Risk Factor Surveillance System were used to study women aged 21–65 years who reported never being screened for cervical cancer. Multivariate logistic regression modeling was used to calculate predicted marginals to examine associations between never being screened and demographic characteristics and health belief model (HBM) constructs by metropolitan statistical area (MSA). After adjusting for all demographics and HBM constructs, prevalence of never being screened was higher for the following women: non-Hispanic Asians/Native Hawaiians/Pacific Islanders (16.5 %, 95 % CI = 13.7 %, 19.8 %) who live in MSAs; those with only a high school diploma who live in MSAs (5.5 %, 95 % CI = 4.7 %, 6.5 %); those living in non-MSAs who reported “fair or poor” general health (4.1 %, 95 % CI = 3.1 %, 5.4 %); and those living in either MSAs and non-MSAs unable to see a doctor within the past 12 months because of cost (MSA: 4.4 %, 95 % CI = 4.0 %, 4.8 %; non-MSA: 3.4 %, 95 % CI = 2.9 %, 3.9 %). The Affordable Care Act will expand access to insurance coverage for cervical cancer screening, without cost sharing for millions of women, essentially eliminating insurance costs as a barrier. Future interventions for women who have never been screened should focus on promoting the importance of screening and reaching non-Hispanic Asians/Native Hawaiians/Pacific Islanders who live in MSAs.     

An HIV prevalence-based model for estimating urban risk populations of injection drug users and men who have sex with men

Issues of cost and complexity have limited the study of the population sizes of men who have sex with men (MSM) and injection drug users (IDUs), two groups at clearly increased risk for human immunodeficiency virus (HIV) and other acute and chronic diseases. We developed a prototypical, easily applied estimation model for these populations and applied it to Miami, Florida. This model combined HIV prevalence estimates, HIV seroprevalence rates, and census data to make plausible estimates of the number and proportion of MSM and IDUs under a number of assumptions. Sensitivity analyses were conducted to test the robustness of the model. The model suggests that approximately 9.5% (plausible range 7.7%–11.3%) of Miami males aged 18 years or older are MSM (point estimate, N=76,500), and 1.4% (plausible range 0.9%–1.9%) of the total population aged 18 years or older are IDUs (point estimate, N=23,700). Males may be about 2.5 times more likely than females to be IDUs. The estimates were reasonably robust to biases. The model was used to develop MSM and IDU population estimates in selected urban areas across Florida and should be replicable in other medium-to-large urban areas. Such estimates could be useful for behavioral surveillance and resource allocation, including enhanced targeting of community-based interventions for primary and secondary HIV prevention. Dr. Friedman is with National Development Research Institutes, Inc. Dr. Gates is with the Urban Institute.     

Multilevel and Spatial–Time Trend Analyses of the Prevalence of Hypertension in a Large Urban City in the USA

We aimed to test two hypotheses that (1) there were significant variations in the prevalence of hypertension (HBP) across neighborhoods in the city of Philadelphia and (2) these variations were significantly explained by the variations in the neighborhood physical and socioeconomic environment (PSE). We used data from the Southeastern Pennsylvania Household Health Surveys in 2002–2004 (study period 1, n = 8,567), and in 2008–2010 (period 2, n = 8,747). An index of neighborhood PSE was constructed using multiple specific measures. The associations of HBP with PSE at the neighborhood level and other risk factors at the individual level were examined using multilevel regression analysis. The results show that age-adjusted prevalence of HBP increased from 30.33 to 33.04 % from study periods 1 to 2 (p < 0.001). An estimate of 44 and 53 % of the variations in the prevalence of HBP could be explained by the variations in neighborhood PSE in study periods 1 and 2, respectively. In conclusion, prevalence of HBP significantly increased from 2002–2004 to 2008–2010. Individuals living in neighborhoods with disadvantaged PSE have significantly higher risk of the prevalence of HBP.     

Estimating the Number of Young Black Men who have Sex with Men (YBMSM) on the South Side of Chicago: Towards HIV Elimination within US Urban Communities

The rate of HIV infection among young Black men who have sex with men (YBMSM) aged 16–29 is increasing significantly in the United States. Prevention in this population would considerably impact future health-care resources given the need for lifelong antiretrovirals. A YBMSM population estimate is needed to assist HIV prevention program planning. This analysis estimates the number of YBMSM aged 16–29 living on the south side of Chicago (SSC), the Chicago HIV epicenter, as the first step in eliminating HIV in this population. Three methods were utilized to estimate the number of YBMSM in the SSC. First, an indirect approach following the formula a = k/b; where a = the estimated number of YBMSM, k = the average YBMSM HIV prevalence estimate, and b = the YBMSM population-based HIV seropositivity rate. Second, data from the most recent National Survey of Family Growth (NSFG) was used to estimate the proportion of Black men who report having sex with a man. Third, a modified Delphi approach was used, which averaged community expert estimates. The indirect approach yielded an average estimate of 11.7 % YBMSM, the NSFG yielded a 4.2 % (95 % CI 2.28–6.21) estimate, and the modified Delphi approach yielded estimates of 3.0 % (2.3–3.6), 16.8 % (14.5–19.1), and 25 % (22.0–27.0); an average of 14.9 %. The crude average of the three methods was 10.2 %. Applied to SSC, this results to 5,578 YBMSM. The estimate of 5,578 YBMSM represents a group that can be feasibly reached with HIV prevention efforts. Population estimates of those most at risk for HIV will help public health officials allocate resources, offering potential for elimination of new HIV cases.     

广东省1986～1999年艾滋病患者与艾滋病病毒感染者流行特征及趋势

目的：分析广东省艾滋病毒者与艾滋病毒感染者（HIV／AIDS）流行现状及影响因素,寻找控制措施,方法：分析全省的HIV常规、哨点、行为监测及实际实验室资料,结果：1996年底首次发现静脉吸毒者HIV阳性以来,HIV／AIDS报告数平均上升86．2％,静脉吸毒占的比例从1996年前的1．4％上升到1999年的91．0％,吸毒者61．3％为HIV－1C亚型,结论：HIV／AIDS疫情已进入快速增长期,静脉吸毒为主要传播途径;当前工作重点是预防HIV／AIDS从吸毒人群向吸以及一般人群传播,并开展行为监测和干预。     

Prevalence and Incidence of HCV Infection among Vietnam Heroin Users with Recent Onset of Injection

HCV infection continues to spread at an alarming rate among IDU populations. The available evidence suggests that HCV is acquired relatively quickly following onset of injection. However, there are few prospective studies of HCV acquisition, particularly among IDU populations in resource-poor settings. A sample of young male heroin injectors with recent onset of injection (<4 years) was recruited in Hanoi, Vietnam for a prospective assessment of the early course of injection (n = 179). Both behavioral and biological assessments (including detailed retrospective assessment of injection initiation) were conducted at baseline and repeated at 6-month intervals for a period of 16 months. Variables associated with HCV infection (p value < 0.05) in bivariate analyses were considered for inclusion in logistic regression models to identify risk factors independently associated with HCV infection. HCV incidence was calculated by using the incidence density approach and was expressed in terms of person-years of observation. The baseline of prevalence of HCV was 46%. HCV significantly increased in relation to time since first injection, from 30% in subjects with ≤10 months of injection risk to 70% in subjects with ≥30 months injection risk (p value = 0.0005). In multivariate logistic regression analysis, increasing age, incarceration in a drug detention facility (OR = 2.54; 95%CI 1.05, 6.15), and time since first injection remained significantly associated with HCV infection. Use of injection as primary mode of administration (OR = 2.56; 95%CI 0.98, 6.69) achieved marginal significance. After 16 months of follow-up, the incidence rate of HCV was 23.35 per 100 person-years and the mean time between first injection and first positive HCV test was 1.2 years. HCV is acquired much more rapidly among new injector populations than previously recognized, demonstrating the need for early behavioral intervention among new heroin-user populations. Particularly critical are interventions that target new heroin user populations, including interventions that improve understanding of viral transmission dynamics, that promote alternative strategies for drug sharing, and that delay initiation of injection.