[Show abstract][Hide abstract] ABSTRACT: Few studies assessing the relationship between active and passive smoking and tuberculosis have used biomarkers to measure smoke exposure. We sought to determine the association between active and passive smoking and LTBI in a representative sample of US adults and children.
We used the 1999-2000 US National Health and Nutrition Examination Survey (NHANES) dataset with tuberculin skin test (TST) data to assess the association between cotinine-confirmed smoke exposure and latent tuberculosis infection (LTBI) among adults ages ≥20 years (n = 3598) and children 3-19 years (n = 2943) and estimate the prevalence of smoke exposure among those with LTBI. Weighted multivariate logistic regression was used to measure the associations between active and passive smoking and LTBI.
LTBI prevalence in 1999-2000 among cotinine-confirmed active, passive, and non-smoking adults and children was 6.0%, 5.2%, 3.3% and 0.3%, 1.0%, 1.5%, respectively. This corresponds to approximately 3,556,000 active and 3,379,000 passive smoking adults with LTBI in the US civilian non-institutionalized population in 1999-2000. Controlling for age, gender, socioeconomic status, race, birthplace (US vs. foreign-born), household size, and having ever lived with someone with TB, adult active smokers were significantly more likely to have LTBI than non-smoking adults (AOR = 2.31 95% CI 1.17-4.55). Adult passive smokers also had a greater odds of LTBI compared with non-smokers, but this association did not achieve statistical significance (AOR = 2.00 95% CI 0.87-4.60). Neither active or passive smoking was associated with LTBI among children. Among only the foreign-born adults, both active (AOR = 2.56 (95% CI 1.20-5.45) and passive smoking (AOR = 2.27 95% CI 1.09-4.72) were significantly associated with LTBI.
Active adult smokers and both foreign-born active and passive smokers in the United States are at elevated risk for LTBI. Targeted smoking prevention and cessation programs should be included in comprehensive national and international TB control efforts.
PLoS ONE 01/2014; 9(3):e93137. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Girl education is believed to be the best means of reducing girl child marriage (marriage <18 years) globally. However, in South Asia, where the majority of girl child marriages occur, substantial improvements in girl education have not corresponded to equivalent reductions in child marriage. This study examines the levels of education associated with female age at marriage over the previous 20 years across four South Asian nations with high rates (>20%) of girl child marriage- Bangladesh, India, Nepal and Pakistan.
PLoS ONE 01/2014; 9(9):e106210. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We examined the relationship between venue stability and consistent condom use (CCU) among female sex workers who inject drugs (FSW-IDUs; n = 584) and were enrolled in a behavioural intervention in two Mexico-USA border cities. Using a generalized estimating equation approach stratified by client type and city, we found venue stability affected CCU. In Tijuana, operating primarily indoors was significantly associated with a four-fold increase in the odds of CCU among regular clients (odds ratio [OR]: 3.77, 95% confidence interval [CI]: 1.44, 9.89), and a seven-fold increase among casual clients (OR: 7.18, 95% CI: 2.32, 22.21), relative to FSW-IDUs spending equal time between indoor and outdoor sex work venues. In Ciudad Juarez, the trajectory of CCU increased over time and was highest among those operating primarily indoors. Results from this analysis highlight the importance of considering local mobility, including venue type and venue stability, as these characteristics jointly influence HIV risk behaviours.
International Journal of STD & AIDS 07/2013; 24(7):523-9. · 1.00 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract In Tijuana, Mexico, sex work is regulated by the municipal government, through registration cards issued to female sex workers (FSWs) for an annual fee. Registration has been associated with decreased drug use and increase condom use and HIV testing. Previously, it was demonstrated that FSWs operating in bars were more likely than street-based FSWs to be registered. This implies that certain venues may be more accessible to local authorities for the enforcement of this type of programme. Taking a novel multilevel approach, we examined whether venue characteristics of bars reflecting greater organised management and visibility affect registration status of FSWs. In an analysis of venue-level characteristics, predictors of being registered were availability of free condoms at work and distance to the main sex strip; however, these were not independently associated after inclusion of FSWs' income, illicit drug use and history of HIV testing. Our findings suggest that sex work regulations may inadvertently exclude venues in which the more vulnerable and less visible FSWs, such as injection drug users and those with limited financial resources, are situated. Efforts to revise or reconsider sex work regulations to ensure that they best promote FSWs' health, human and labour rights are recommended.
Global Public Health 03/2013; · 0.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background
Employing innovative mapping and spatial analyses of individual and neighborhood environment data, we examined the social, physical and structural features of overlapping street-based sex work and drug scenes and explored the utility of a ‘spatial isolation index’ in explaining exchanging sex for drugs and exchanging sex while high.
Analyses drew on baseline interview and geographic data (Jan/10-Oct/11) from a large prospective cohort of street and off-street sex workers (SWs) in Metropolitan Vancouver and external publically-available, neighborhood environment data. An index measuring ‘spatial isolation’ was developed from seven indicators measuring features of the built environment within 50 m buffers (e.g. industrial or commercial zoning, lighting) surrounding sex work environments. Bivariate and multivariable logistic regression was used to examine associations between the two outcomes (exchanged sex for drugs; exchanged sex while high) and the index, as well as each individual indicator.
Of 510 SWs, 328 worked in street-based/outdoor environments (e.g. streets, parks, alleys) and were included in the analyses. In multivariable analysis, increased spatial isolation surrounding street-based/outdoor SWs’ main places of servicing clients as measured with the index was significantly associated with exchanging sex for drugs. Exchanging sex for drugs was also significantly positively associated with an indicator of the built environment suggesting greater spatial isolation (increased percent of parks) and negatively associated with those suggesting decreased spatial isolation (increased percent commercial areas, increased count of lighting, increased building footprint). Exchanging sex while high was negatively associated with increased percent of commercial zones but this association was removed when adjusting for police harassment.
The results from our exploratory study highlight how built environment shapes risks within overlapping street-based sex work and drug scenes through the development of a novel index comprised of multiple indicators of the built environment available through publicly available data, This study informs the important role that spatially-oriented responses, such as safer-environment interventions, and structural responses, such as decriminalization of sex work can play in improving the health, safety and well-being of SWs.
The International journal on drug policy 01/2013; · 2.54 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The northwest border city of Tijuana is Mexico's fifth largest and is experiencing burgeoning drug use and human immunodeficiency virus (HIV) epidemics. Because local geography influences disease risk, we explored the spatial distribution of HIV among injection drug users (IDUs). From 2006–2007, 1,056 IDUs were recruited using respondent-driven sampling and then followed for eighteen months. Participants underwent semiannual surveys, mapping, and testing for HIV, tuberculosis, and syphilis. Using average nearest neighbor and Getis-Ord Gi* statistics, locations where participants lived, worked, bought drugs, and injected drugs were compared with HIV status and environmental and behavioral factors. Median age was thirty-seven years; 85 percent were male. Females had higher HIV prevalence than males (10.2 percent vs. 3.4 percent; p = 0.001). HIV cases at baseline (n = 47) most strongly clustered by drug injection sites (Z score = –6.173, p < 0.001), with a 16-km2 hotspot near the Mexico–U.S. border, encompassing the red-light district. Spatial correlates of HIV included syphilis infection, female gender, younger age, increased hours on the street per day, and higher number of injection partners. Almost all HIV seroconverters injected within a 2.5-block radius of each other immediately prior to seroconversion. Only history of syphilis infection and female gender were strongly associated with HIV in the area where incident cases injected. Directional trends suggested a largely static epidemic until July through December 2008, when HIV spread to the southeast, possibly related to intensified violence and policing that spiked in the latter half of 2008. Although clustering allows for targeting interventions, the dynamic nature of epidemics suggests the importance of mobile treatment and harm reduction programs. La ciudad fronteriza de Tijuana, en la frontera noroeste de México, la quinta más grande del país, está padeciendo una tremenda epidemia de uso de drogas y de contagio con el virus de inmunodeficiencia humana (VIH). Debido a que la geografía local influye sobre el riesgo de contraer la enfermedad, exploramos la distribución espacial del VIH entre los usuarios de drogas inyectables (IDU, acrónimo inglés). Desde 2006-2007 se reclutaron para el estudio 1.056 IDUs utilizando un muestreo de base entre quienes respondieron, para ser seguidos luego durante dieciocho meses. Los participantes fueron sometidos a estudios de duración semestral, ubicación cartográfica y exámenes de laboratorio para VIH, tuberculosis y sífilis. Utilizando estadísticas del promedio de vecino más cercano y Geits-Ord GI*, las localizaciones donde los participantes vivían, trabajaban, compraban drogas y se las inyectaban, se compararon con el estatus del VIH y con factores ambientales y de comportamiento. La edad promedio fue de treinta y siete años; el 85 por ciento de los participantes fueron masculinos. Las mujeres registraron una más alta prevalencia del VIH que los varones (10.2 por ciento vs. 3.4 por ciento; p = 0.001). Los casos de VIH en el nivel base (n = 47) se agrupaban fuertemente alrededor de los sitios donde se producía la inyección de drogas (el puntaje de Z = 6.173, p < 0.001), con un punto crítico de 16-km2 cerca de la frontera México-EE.UU., el cual abarcaba todo el distrito de farol-rojo. Los correlatos espaciales del VIH incluyeron infección sifilítica, género femenino, edad más joven, mayor número de horas por día en la calle y un mayor número de compañeros de inyección. Casi todos los seropositivos con VIH se habían inyectado dentro de un radio de 2.5 manzanas de cada uno de ellos inmediatamente antes de la seroconversión. Solamente la historia de infección sifilítica y género femenino estuvieron fuertemente asociados con el VIH en el área donde ocurrieron casos incidentales de inyección. Las tendencias direccionales sugirieron una epidemia en gran medida estática hasta el tiempo transcurrido de julio a diciembre de 2008, cuando el VIH se difundió hacia el sudeste, algo posiblemente relacionado con la intensificación de la violencia y el incremento de la acción policial, que alcanzaron su pico en la segunda mitad del 2008. Aunque la aglomeración facilita la intervención claramente enfocada, la naturaleza dinámica de la epidemia sugiere la importancia de los tratamientos móviles y los programas de reducción del daño social.
Annals of the Association of American Geographers 09/2012; 102(5):1190-1199. · 2.17 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: FSWs who inject drugs (FSW-IDUs) can acquire HIV through high risk sexual and injection behaviors. We studied correlates of HIV infection among FSW-IDUs in northern Mexico, where sex work is quasi-legal and syringes can be legally obtained without a prescription.
FSW-IDUs>18 years old who reported injecting drugs and recent unprotected sex with clients in Tijuana and Ciudad Juarez underwent surveys and HIV/STI testing. Logistic regression identified correlates of HIV infection.
Of 620 FSW-IDUs, prevalence of HIV, gonorrhea, Chlamydia, trichomonas, syphilis titers ≥1:8, or any of these infections was 5.3%, 4%, 13%, 35%, 10% and 72%, respectively. Compared to other FSW-IDUs, HIV-positive women were more likely to: have syphilis titers ≥1:8 (36% vs. 9%, p<0.001), often/always inject drugs with clients (55% vs. 32%, p = 0.01), and experience confiscation of syringes by police (49% vs. 28%, p = 0.02). Factors independently associated with HIV infection were syphilis titers ≥1:8, often/always injecting with clients and police confiscation of syringes. Women who obtained syringes from NEPs (needle exchange programs) within the last month had lower odds of HIV infection associated with active syphilis, but among non-NEP attenders, the odds of HIV infection associated with active syphilis was significantly elevated.
Factors operating in both the micro-social environment (i.e., injecting drugs with clients) and policy environment (i.e., having syringes confiscated by police, attending NEPs) predominated as factors associated with risk of HIV infection, rather than individual-level risk behaviors. Interventions should target unjustified policing practices, clients' risk behaviors and HIV/STI prevention through NEPs.
PLoS ONE 01/2011; 6(4):e19048. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sex work is regulated in the Zona Roja (red light district) in Tijuana, Mexico, where HIV and sexually transmitted disease (STD) prevalence is high among female sex workers (FSWs). We examined the spatial distribution of STDs by work venue among FSWs in Tijuana.
FSWs aged 18 years and older who reported unprotected sex with ≥ 1 client in the past 2 months underwent testing for HIV, syphilis, gonorrhea, and Chlamydia. HIV/STDs were mapped by venue (i.e., bar, hotel) and Getis-Ord Gi statistics were used to identify geographic hotspots. High-risk venues were then identified using a standardized STD ratio (high risk defined as a ratio ≥ 1.25). Logistic regression was used to assess correlates of working at a high risk venue.
Of 474 FSWs, 176 (36.4%) had at least 1 bacterial sexually transmitted infection (STI); 36 (7.6%) were HIV-positive. Within the Zona Roja, 1 venue was identified as a geographic "hotspot," with a higher than expected number of HIV/STD-positive FSW (P < 0.05) as compared to neighboring venues. Using the STD ratio definition, 11 venues were identified as high-risk; FSWs working in these locations had higher education, were more likely to report always using drugs with sex, and having mostly US clients. They were less likely to be registered FSWs or to live at their work venue.
A relatively few number of sex work venues accounted for a large proportion of the HIV/STI burden among FSWs in Tijuana. Structural interventions that focus on sex work venues could help increase STI diagnosis, prevention, and treatment among FSWs in Tijuana.
[Show abstract][Hide abstract] ABSTRACT: To identify correlates of active syphilis infection among female sex workers (FSWs) in Tijuana and Ciudad Juarez.
Cross-sectional analyses of baseline interview data. Correlates of active syphilis (antibody titers >1 : 8) were identified by logistic regression. Setting Tijuana and Ciudad Juarez, two Mexican cities on the US border that are situated on major drug trafficking routes and where prostitution is quasi-legal.
A total of 914 FSWs aged > or =18 years without known human immunodeficiency virus (HIV) infection who had had recent unprotected sex with clients.
Baseline interviews and testing for syphilis antibody using Treponema pallidum particle agglutination (TPPA) and rapid plasma reagin (RPR) tests.
Median age and duration in sex work were 32 and 4 years, respectively. Overall, 18.0% had ever injected drugs, 14.2% often or always used illegal drugs before or during sex in the past month, 31.4% had clients in the last 6 months who injected drugs, and 68.6% reported having clients from the United States. Prevalence of HIV and active syphilis were 5.9% and 10.3%, respectively. Factors independently associated with active syphilis included injecting drugs (AOR: 2.39; 95% CI: 1.40, 4.08), using illegal drugs before or during sex (AOR: 2.06; 95% CI: 1.16, 3.65) and having any US clients (AOR: 2.85; 95% CI: 1.43, 5.70).
Among female sex workers in Tijuana and Ciudad Juarez, drug-using behaviors were associated more closely with active syphilis than were sexual behaviors, suggesting the possibility of parenteral transmission of T. pallidum. Syphilis eradication programs should consider distributing sterile syringes to drug injectors and assisting FSWs with safer-sex negotiation in the context of drug use.
[Show abstract][Hide abstract] ABSTRACT: Pasa la Voz (spread the word) is a human immunodeficiency virus (HIV) prevention methodology inspired by respondent-driven sampling (RDS) that uses social networks to access hard-to-reach populations. As field testing showed the approach to be efficacious among at-risk women in West Texas and Southern New Mexico, we set out to evaluate the methodology in a Mexican context. A local community organization, Programa Compañeros, first implemented a traditional one-on-one outreach strategy using promotoras (outreach workers) in Ciudad Juarez, Mexico, from September 2005 to January 2006. This was followed by implementation of Pasa la Voz from February 2006 to January 2007. The percentage of women agreeing to be tested increased from 11.9% to 49.9%, and staff time declined from 22.70 hours to 3.68 hours per HIV test, comparing the one-on-one with the Pasa la Voz methodology, respectively. Pasa la Voz was successful at imparting a cost-savings prevention education program with significant increases in the number of at-risk women being tested for HIV.
Public Health Reports 01/2010; 125(4):528-33. · 1.42 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Tijuana is situated on the Mexico-USA border adjacent to San Diego, CA, on a major drug trafficking route. Increased methamphetamine trafficking in recent years has created a local consumption market. We examined factors associated with methamphetamine use and routes of administration by gender among injection drug users (IDUs). From 2006-2007, IDUs > or =18 years old in Tijuana were recruited using respondent-driven sampling, interviewed, and tested for HIV, syphilis, and TB. Logistic regression was used to assess associations with methamphetamine use (past 6 months), stratified by gender. Among 1,056 participants, methamphetamine use was more commonly reported among females compared to males (80% vs. 68%, p < 0.01), particularly, methamphetamine smoking (57% vs. 34%; p < 0.01). Among females (N = 158), being aged >35 years (AOR, 0.2; 95% CI, 0.1-0.6) was associated with methamphetamine use. Among males (N = 898), being aged >35 years (AOR, 0.5; 95% CI, 0.3-0.6), homeless (AOR, 1.4 (0.9-2.2)), and ever reporting sex with another male (MSM; AOR, 1.9; 95% CI, 1.4-2.7) were associated with methamphetamine use. Among males, a history of MSM was associated with injection, while sex trade and >2 casual sex partners were associated with multiple routes of administration. HIV was higher among both males and females reporting injection as the only route of methamphetamine administration. Methamphetamine use is highly prevalent among IDUs in Tijuana, especially among females. Routes of administration differed by gender and subgroup which has important implications for tailoring harm reduction interventions and drug abuse treatment.
Journal of Urban Health 07/2009; 86(5):760-75. · 1.89 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated the relationship between environmental-structural factors and condom-use negotiation with clients among female sex workers.
We used baseline data from a 2006 Vancouver, British Columbia, community-based cohort of female sex workers, to map the clustering of "hot spots" for being pressured into unprotected sexual intercourse by a client and assess sexual HIV risk. We used multivariate logistic modeling to estimate the relationship between environmental-structural factors and being pressured by a client into unprotected sexual intercourse.
In multivariate analyses, being pressured into having unprotected sexual intercourse was independently associated with having an individual zoning restriction (odds ratio [OR] = 3.39; 95% confidence interval [CI] = 1.00, 9.36), working away from main streets because of policing (OR = 3.01; 95% CI = 1.39, 7.44), borrowing a used crack pipe (OR = 2.51; 95% CI = 1.06, 2.49), client-perpetrated violence (OR = 2.08; 95% CI = 1.06, 4.49), and servicing clients in cars or in public spaces (OR = 2.00; 95% CI = 1.65, 5.73).
Given growing global concern surrounding the failings of prohibitive sex-work legislation on sex workers' health and safety, there is urgent need for environmental-structural HIV-prevention efforts that facilitate sex workers' ability to negotiate condom use in safer sex-work environments and criminalize abuse by clients and third parties.
American Journal of Public Health 03/2009; 99(4):659-65. · 3.93 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To examine associations between migration and sexually transmitted infection (STI) prevalence among Mexican female sex workers (FSW).
FSW aged 18 years and older in Tijuana, Baja California (BC) underwent interviews and testing for HIV, syphilis, gonorrhoea and chlamydia. Multivariate logistic regressions identified correlates of STI.
Of 471 FSW, 79% were migrants to BC. Among migrant FSW, prevalence of HIV, syphilis, gonorrhoea, chlamydia and any STI was 6.6%, 13.2%, 7.8%, 16.3% and 31.1% compared with 10.9%, 18.2%, 13.0%, 19.0% and 42.4% among FSW born in BC. A greater proportion of migrant FSW were registered with local health services and were ever tested for HIV. Migrant status was protective for any STI in unadjusted models (unadjusted odds ratio 0.61, 95% CI 0.39 to 0.97). In multivariate models controlling for confounders, migrant status was not associated with an elevated odds of STI acquisition and trended towards a protective association.
Unexpectedly, migrant status (vs native-born status) appeared protective for any STI acquisition. It is unclear which social or economic conditions may protect against STI and whether these erode over time in migrants. Additional research is needed to inform our understanding of whether or how geography, variations in health capital, or social network composition and information-sharing attributes can contribute to health protective behaviours in migrant FSW. By capitalising on such mechanisms, efforts to preserve protective health behaviours in migrant FSW will help control STI in the population and may lead to the identification of strategies that are generalisable to other FSW.
[Show abstract][Hide abstract] ABSTRACT: As stigma is a socially constructed concept, it would follow that stigma related to sexual behaviours and sexually transmitted infections would carry with it many of the gender-based morals that are entrenched in social constructs of sexuality. In many societies, women tend to be judged more harshly with respect to sexual morals, and would therefore have a different experience of stigma related to sexual behaviours as compared to men. While a variety of stigma scales exist for sexually transmitted infections (STIs) in general; none incorporate these female-specific aspects. The objective of this study was to develop a scale to measure the unique experience of STI-related stigma among women.
A pool of items was identified from qualitative and quantitative literature on sexual behaviour and STIs among women. Women attending a social evening program at a local community health clinic in a low-income neighbourhood with high prevalence of substance use were passively recruited to take part in a cross-sectional structured interview, including questions on sexual behaviour, sexual health and STI-related stigma. Exploratory factor analysis was used to identify stigma scales, and descriptive statistics were used to assess the associations of demographics, sexual and drug-related risk behaviours with the emerging scales.
Three scales emerged from exploratory factor analysis--female-specific moral stigma, social stigma (judgement by others) and internal stigma (self-judgement)--with alpha co-efficients of 0.737, 0.705 and 0.729, respectively. In this population of women, internal stigma and social stigma carried higher scores than female-specific moral stigma. Aboriginal ethnicity was associated with higher internal and female-specific moral stigma scores, while older age (>30 years) was associated with higher female-specific moral stigma scores.
Descriptive statistics indicated an important influence of culture and age on specific types of stigma. Quantitative researchers examining STI-stigma should consider incorporating these female-specific factors in order to tailor scales for women.
BMC Women s Health 12/2008; 8:21. · 1.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Since the advent of highly active antiretroviral therapy (HAART), AIDS-related hospitalizations have decreased. The objective of this study was to assess the impact of adherence on hospitalization among antiretroviral-naïve HIV-infected persons initiating HAART. Methods: Analysis was based on a cohort of individuals initiating HAART between 1996 and 2001. The primary outcome was hospitalization for one or more days. Survival methods were used to assess the impact of adherence on hospitalization.
Of 1605 eligible participants, 672 (42%) were hospitalized for one or more days after initiating HAART. Median adherence levels were 92 (IQR: 58, 100) and 100 (IQR: 83, 100) among those ever and never hospitalized, respectively. After controlling for confounders, those with <95% adherence had 1.88 times (95% CI: 1.60, 2.21) higher risk for hospitalization.
Suboptimal adherence among HIV-infected patients taking HAART predicts hospitalization. Identifying and addressing factors contributing to poor adherence early in treatment could improve patient care and lower hospitalization costs.
Journal of the International Association of Physicians in AIDS Care (JIAPAC) 09/2008; 7(5):238-44.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to assess the association of sexually transmitted disease (STD)-related stigma on sexual health care behaviors, including Papanicolaou smears and STD testing/treatment, among women from a high-risk community.
Descriptive statistics were used to assess the association of demographics, sexual and drug-related risk behaviors, and 3 measures of STD-stigma (internal, social, and tribal stigma, the latter referring to "tribes" of womanhood) with sexual health care in the past year. Pearson's chi-square test and Mann-Whitney test were used to assess significance. Multivariate logistic models were used to determine the association of STD-stigma with sexual health care after controlling for other factors.
Lower internal stigma score was marginally associated with reporting an STD test in the past year [median score (interquartile range) for those reporting and not reporting an STD test were 0.79 (0.30-1.59) and 1.35 (0.67-1.93), respectively]. In an adjusted model, internal stigma retained a negative association with reporting of STD testing in the past year (adjusted odds ratio, 0.92; 95% confidence interval, 0.85-0.99).
Most women had received a Papanicolaou smear in the past year, and none of the STD-stigma scales were associated with reporting this behavior. Internal stigma retained an association with not having any STD test or treatment. Although sexual stigma is a deeply rooted social construct, paying attention to how prevention messages and STD information are delivered may help remove one barrier to sexual health care.
Sex Transm Dis 07/2008; 35(6):553-7. · 2.59 Impact Factor