Faculty Bibliography

OBJECTIVES: We investigated risk factors for fatal motor vehicle crashes on slippery roads in the Northeastern United States, 1998-2002. METHODS: We analyzed data from the Fatality Analysis Reporting System of the National Highway Traffic Safety Administration. RESULTS: Rates of crashes on slippery roads, and ratios of crashes on slippery roads to crashes on dry roads, were greatest among the youngest drivers. Among those aged 16 to 19 years, logistic regression analysis showed significant, independent risks associated with excessive speed for conditions (odds ratio [OR]=1.38), time of day (OR=1.80 for 5:00 to 9:00 am vs 10:00 am to 2:00 pm), time of year (OR=6.17 for January vs July), type of road (OR=1.27 for rural vs urban roads ), and age (OR=1.19 for those aged 16 to 17 years vs those aged 18 to 19 years). Licensure from states with graduated licensing programs was protective against crashes attributed to swerving on slippery roads (adjusted OR = 0.63). Risk factors among drivers older than 19 years were similar but peaked at different times of day and included increased risks for women compared with men. CONCLUSIONS: Driver training programs need to better address hazards presented by slippery roads

The biological correlates of an effective immune response that could contain or prevent HIV infection remain elusive despite substantial scientific accomplishments in understanding the interactions among the virus, the individual and the community. The observation that some individuals appear to possess resistance to HIV infection or its consequences has generated a host of epidemiologic investigations to identify biological or behavioral characteristics of these individuals. These data might hold the keys to developing appropriate strategies for mimicking the effective responses of those who appear immune. In this paper we review genetic mechanisms including the role of chemokines and their receptors, cytokines, host genetic immune response to HIV infection, local immune response correlating with behavioral variables, co-infection and immune based mechanisms that have been elucidated so far. We offer suggestions for how to use these observations as platforms for future research to further understand natural resistance to HIV infection through cohort studies, population genotype sampling, mathematical modeling of virus-host interactions and behavioral analyses

Limited information is available on the prevalence among rural Africans of host genetic polymorphisms conferring resistance to HIV-1 infection or slowing HIV disease progression. We report the allelic frequencies of the AIDS-related polymorphisms CCR2-64I, SDF1-3'A, and CCR5-Delta32 in 321 volunteers from 7 ethnic groups in Cameroon. Allelic frequencies differed among the 7 ethnic groups, ranging from 10.8% to 31.3% for CCR2-64I and 0.0% to 7.1% for SDF1-3'A. No CCR5-Delta32 alleles were found. HIV seroprevalence was 6.9% in the total population and peaked at younger ages in girls and women than in boys and men. Among 15- to 54-year-olds, HIV seroprevalence varied from 2.0% to 11.1% among the village populations. Conditional logistic regression analysis using data from boys and men aged 15 to 54 years showed the number of CCR2-64I alleles to be a significant risk factor for HIV seropositivity (odds ratio per allele adjusted for age and matched on ethnic group = 6.3, 95% confidence interval: 1.3-30.3); this association was not found in women. The findings are consistent with the hypothesis that CCR2-64I alleles may delay HIV disease progression without affecting susceptibility to infection among men. We did not observe this relation among women, and other factors, such as multiple pregnancies or maternal stressors (eg, breastfeeding), may have masked any protective effect of CCR2-64I alleles. Further study of this issue among women is warranted. SDF1-3'A did not differ between HIV-seropositive and HIV-seronegative individuals but was associated with increasing age among HIV-seronegative women, suggesting a protective effect against HIV-1 infection

Helicobacter pylori prevalence is higher in developing countries than in industrialized countries, and within the latter, higher among immigrants than among nativeborn residents. Using a point-prevalence survey, we sought to identify risk factors for H. pylori seropositivity in US urban East Asian-born populations. At a clinic in New York City, we consecutively enrolled 194 East Asian-born adults, who then responded to a survey and provided a blood sample. Assays were performed to detect IgG antibodies against whole cell (WC) and cytotoxin associated gene A (CagA) antigens of H. pylori. For this group (mean age 50.2+/-14.7 years), the mean period of residence in the United States was 11.9+/-7.7 years. The total H. pylori seroprevalence was 70.1%, with highest (81.4%) in Fujianese immigrants. Multiple logistic regression analysis indicated an independent association of H. pylori seropositivity with Fujianese origin [odds ratios (OR) =2.3, 95% confidence interval (95% CI) =1.05-5.0] and inverse associations with period in the United States (OR per year of residency in the United States =0.95, 95% CI =0.91-0.99) and with a history of dyspepsia (OR for a history of stomach pain =0.52, 95% CI =0.3-1.0). We conclude that H. pylori is highly prevalent among recent East Asian immigrants, especially among Fujianese. The protective effects of history of dyspepsia and duration in the United States suggest that these may be markers for antibiotic therapies.

Increased risk behavior among participants in HIV vaccine efficacy trials has been a concern. This study evaluated HIV sexual risk behavior among 5095 HIV-negative men who have sex with men (MSM) and 308 women enrolled in a randomized, double-blind, placebo-controlled efficacy trial of a bivalent rgp120 vaccine at 61 sites, primarily in North America. Sexual risk behavior data were collected at baseline and semiannually for 36 months. Overall, sexual risk behavior did not exceed baseline levels during the trial. Among MSM, younger age (< or =30 years), perceived assignment to vaccine, and nonblack race were associated with an increased probability of unprotected anal sex. Among women, unprotected vaginal sex initially decreased but was statistically equivalent to baseline by 24 months, whereas unprotected vaginal sex with HIV-infected partners decreased from baseline, where it remained throughout the trial. HIV sexual risk behavior did not increase among trial participants; however, it was substantial throughout the trial. Consistently high levels of risk behavior and the association of these behaviors to perceived assignment and demographic variables underscore the need for vigilant HIV risk reduction counseling, informed consent, and educational processes in the context of HIV vaccine efficacy trials

OBJECTIVE:: To describe recruitment and baseline epidemiologic characteristics of volunteers in the first phase 3 placebo-controlled trial of a recombinant gp120 HIV vaccine (AIDSVAX B/B). METHODS:: Volunteers were gay/bisexual men or women at risk for sexually transmitted HIV infection. Recruitment strategies, demographics, and risk factors were assessed. HIV status was determined by standard HIV-1 antibody assays. Seronegative/viremic HIV infection at enrollment was determined using the HIV-1 nucleic acid test. RESULTS:: From June 1998 through October 1999, 5417 of 7185 volunteers screened were enrolled at 61 sites in the United States, Canada, and The Netherlands. Successful recruitment methods included distribution of study information at gay venues, advertising and media coverage, and referrals from volunteers. Most volunteers were altruistically motivated, men (98%), young (median, 36 years), white (83%), well educated (61% college education or more), and at high risk for HIV during the 6 months before enrollment. At baseline, 14 were HIV infected (12 were seronegative but viremic; 2 were seropositive and viremic). CONCLUSION:: Men and women at high risk for sexually transmitted HIV infection were successfully recruited for the first phase 3 HIV vaccine efficacy trial. Knowledge of recruitment and baseline epidemiologic characteristics of participants in this trial will provide valuable guidance for designing and conducting future trials

As part of a larger investigation examining genetic immunity to HIV, we undertook a cross-sectional investigation of 97 HIV-seronegative men who have sex with men (MSM). Our aim was to better understand the factors to which these men attributed their HIV serostatus and to relate these attributions to sexual risk taking. Three beliefs were related to sexual risk taking with HIV-negative/status unknown casual partners: (a) medication treatment advances, (b) the low probability related to HIV transmission, and (c) a healthy immune system, capable of resisting infection. A multivariate regression model suggested that use of recreational drugs, in combination with the belief that treatment advances reduce the risk of HIV seroconversion, in part, may explain the frequency with which individuals engage in unprotected anal receptive intercourse. Our findings suggest that MSM who intentionally engage in unprotected anal sex may be influenced by perceptions that medical advances have mitigated the threat of HIV and corroborate previous studies depicting an intimate relationship between illicit drug use and sexual risk taking

Over the past 20 years, we have observed a paucity of morbidity and mortality due to cardiovascular disease among drug users in a methadone maintenance clinic. The present study investigated whether long-term exposure to opiates or opioids is associated with decreased severity of coronary artery disease (CAD) by comparing 98 decedents with methadone or opiates (M/O) in their blood at autopsy with 97 frequency-matched decedents without M/O. Severe CAD was found significantly less often in M/O-positive decedents (5 of 98) than in M/O-negative decedents (16 of 97). Multiple logistic regression analysis contrasting those with moderate or severe CAD to those with no or mild CAD yielded an odds ratio of 0.43 (95% confidence interval 0.20 to 0.94) for M/O positivity after adjustment for potential confounding. Long-term opiate exposure thus may mitigate CAD severity and its often fatal consequences

OBJECTIVE: To evaluate HIV-1 antibody seroprevalence and risk factors for HIV seropositivity in rural areas of Cameroon. METHOD: The prevalences of HIV antibodies in 53 villages in rural Cameroon visited during May-October 2000 were determined with an HIV1/2 rapid assay, standard ELISA, and western blot. Demographic data and risk factors were elicited via face-to-face interviews with a structured questionnaire. RESULTS: HIV seroprevalence was 5.8% (243/4156, 95% confidence interval [CI] = 5.1-6.6) overall, 6.3% (151/2394, 95% CI = 5.4-7.4) among females and 5.2% (92/1762, 95% CI = 4.3-6.4) among males. HIV seroprevalence among persons aged 15 - 70 years did not differ significantly by province (5.6% in Center, 4.5% in East, 6.9% in South, and 5.8% in South-West) ( =.10). Analysis of age- and gender-standardized prevalence by village across provinces indicated a near-significant difference (nonparametric Wilcoxon signed rank test, =.06), with highest prevalence in South-West, followed by South, Center, and East. Multivariate analysis revealed that single women were significantly more likely to be HIV seropositive than were married or widowed women. Women with a history of sexual relations while traveling were at significantly increased risk of HIV seropositivity (OR adjusted for age and marital status = 2.4, 95% CI = 1.4-9.7). Among men, those who reported ever having a sexually transmitted disease were at significantly increased risk of HIV-seropositivity (OR adjusted for age = 1.8, 95% CI = 1.1-2.8). CONCLUSION: We have documented a wide range of HIV prevalences among rural villages of Cameroon. Age, marital status (in women) and sexual risk factors appear to be associated with HIV infection in this setting

OBJECTIVES: To identify situational and partner characteristics associated with unprotected sex among women at risk for HIV infection. METHODS: The most recent unprotected and protected sexual encounters were compared using a case-crossover design among 1,647 women enrolled in a prospective cohort study conducted in six U.S. cities. Information collected via audio computer-assisted self-interview included detailed situational and partner characteristics for participants' most recent sexual encounters, with and without condom use. Paired odds ratios (ORs) and 95% confidence intervals were calculated for situational or partner characteristics that may differ between unprotected and protected sexual encounters, using conditional logistic regression. RESULTS: In the adjusted analysis, partner age of older than 40 years (OR = 2.42), partner type (OR = 2.45 for a 'steady' partner), partner use of alcohol (OR = 1.67) and drugs within 2 hours (OR = 1.42) of the sexual encounter, time since the encounters (OR = 0.41, 0.33, and 0.19), and exchange of sex for money or drugs (OR = 0.68) remained significantly associated with women's most recent unprotected sexual encounter. CONCLUSIONS: Considerations related to partner and relationship characteristics should provide information for the development of interventions for women