Yijian Huang

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OBJECTIVES Risk factors for HIV acquisition were examined in a recent cohort of men who have sex with men (MSM). DESIGN A longitudinal analysis of 4295 HIV-negative MSM enrolled in a randomized behavioral intervention trial conducted in six US cities. METHODS MSM were enrolled and assessed for HIV infection and risk behaviors semi-annually, up to 48(More)
Prior reports associating substance use with sexual risk behavior have generally used summary measures and have not adjusted for participants' background levels of substance use. In this 1999-2001 US study (the EXPLORE study), the authors determined whether substance use during sex was independently associated with sexual risk during recent sexual episodes,(More)
OBJECTIVES We describe the prevalence of risk behaviors at baseline among men who have sex with men (MSM) who were enrolled in a randomized behavioral intervention trial conducted in 6 US cities. METHODS Data analyses involved MSM who were negative for HIV antibodies and who reported having engaged in anal sex with 1 or more partners in the previous year.(More)
OBJECTIVE Antiretroviral drug treatment may be complicated in individuals infected with antiretroviral drug-resistant or non-subtype B HIV-1 strains. HIV-1 tropism may also affect disease progression. We analyzed antiretroviral drug resistance, HIV-1 subtype, and HIV-1 tropism among 195 men who have sex with men from six major cities in the United States,(More)
Commercial breeding programs seek to maximise the rate of genetic gain while minimizing the costs of attaining that gain. Genomic information offers great potential to increase rates of genetic gain but it is expensive to generate. Low-cost genotyping strategies combined with genotype imputation offer dramatically reduced costs. However, both the costs and(More)
Missing data, measurement error, and misclassification are three important problems in many research fields, such as epidemiological studies. It is well known that missing data and measurement error in covariates may lead to biased estimation. Misclassification may be considered as a special type of measurement error, for categorical data. Nevertheless, we(More)
Quantile regression has been advocated in survival analysis to assess evolving covariate effects. However, challenges arise when the censoring time is not always observed and may be covariate-dependent, particularly in the presence of continuously-distributed covariates. In spite of several recent advances, existing methods either involve algorithmic(More)
We estimated the survival and hospitalization among frequent hemodialysis users in comparison to those patients undergoing thrice-weekly conventional hemodialysis. All patients had similar characteristics and medical histories. In this cohort study of frequent hemodialysis users and propensity score-matched controls, the collaborating clinicians identified(More)
OBJECTIVES We describe the intervention tested in EXPLORE, an HIV prevention trial aimed at men who have sex with men (MSM), and test the empirical basis of the individually tailored intervention. METHODS Data on participants' self-efficacy, communication skills, social norms, and enjoyment of unprotected anal intercourse were examined in relation to(More)
BACKGROUND Investigation of factors associated with variation in dialysis patient employment has focused primarily on patient-level factors. Little is known about facility-level factors that may be associated with patient employment. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS The ESRD Facility Survey (CMS-2744A) began in 2004 to collect counts of(More)