Los Angeles County Department of Health Services

Despite the many accomplishments of public health, a greater attention to evidence-based approaches is warranted. This article reviews the concepts of evidence-based public health (EBPH), on which formal discourse originated about a decade ago. Key components of EBPH include making decisions on the basis of the best available scientific evidence, using data and information systems systematically, applying program-planning frameworks, engaging the community in decision making, conducting sound evaluation, and disseminating what is learned. Three types of evidence have been presented on the causes of diseases and the magnitude of risk factors, the relative impact of specific interventions, and how and under which contextual conditions interventions were implemented. Analytic tools (e.g., systematic reviews, economic evaluation) can be useful in accelerating the uptake of EBPH. Challenges and opportunities (e.g., political issues, training needs) for disseminating EBPH are reviewed. The concepts of EBPH outlined in this article hold promise to better bridge evidence and practice.

In Los Angeles County, California, 142 cases of human listeriosis were reported from January 1 through August 15, 1985. Ninety-three cases (65.5 percent) occurred in pregnant women or their offspring, and 49 (34.5 percent) in nonpregnant adults. There were 48 deaths: 20 fetuses, 10 neonates, and 18 nonpregnant adults. Of the nonpregnant adults, 98 percent (48 of 49) had a known predisposing condition. Eighty-seven percent (81 of 93) of the maternal/neonatal cases were Hispanic. Of the Listeria monocytogenes isolates available for study, 82 percent (86 of 105) were serotype 4b, of which 63 of 86 (73 percent) were the same phage type. A case-control study implicated Mexican-style soft cheese (odds ratio, 5.5; 95 percent confidence interval, 1.2 to 24.8) as the vehicle of infection; a second case-control study showed an association with one brand (Brand A) of Mexican-style soft cheese (odds ratio, 8.5; 95 percent confidence interval, 2.4 to 26.2). Laboratory study confirmed the presence of L. monocytogenes serogroup 4b of the epidemic phage type in Brand A Mexican-style cheese. In mid-June, all Brand A cheese was recalled and the factory was closed. An investigation of the cheese plant suggested that the cheese was commonly contaminated with unpasteurized milk. We conclude that the epidemic of listeriosis was caused by ingestion of Brand A cheese contaminated by one phage type of L. monocytogenes serotype 4b.

Abstract This article reviews the emissions, environmental fate and transport, analytical chemistry, uptake and metabolism, toxicology, and human epidemiology of chromium. Chromium is unique among regulated toxic elements in the environment in that different species of chromium, specifically chromium (III) and chromium (VI), are regulated in different ways, in contrast to other toxic elements where the oxidation state is not distinguished. In both industrial and environmental situations chromium (III) and chromium (VI) can inter-convert, with reduction of chromium (VI) to chromium (III) generally being favored in most environmental situations. Chromium released into the air, water, and soil can be transported among the various environmental media through various intermedia transport processes. Once in the environment, chromium can be taken up by human and other ecological receptors. Chromium (III) is generally absorbed through cell membranes albeit to a significantly lesser degree than chromium (VI). Because most of the biosphere is reducing for chromium (VI) and chromium (III) is relatively immobile, there is little bioconcentration or biomagnification of chromium (VI). Chromium appears to be a nutrient for at least some plants and animals, including humans, although chromium (VI) species have been reported to be toxic to bacteria, plants, and animals. Human toxicity includes lung cancer, liver, kidney and gastric damage, and epidermal irritation and sensiti-zation. However, it is noted that medical, toxicological, and epidemiological evidence suggests that not all compounds containing chromium (VI) species (e.g., chromate salts) are carcinogenic. Keywords: chromium (III)chromium (VI)intermedia transport and transformationsexposuretoxicology.

THE number of cases of tuberculosis reported annually in the United States declined steadily from 84,304 in 1953 to 22,255 in 1984.1,2 In a dramatic reversal of this trend, the number rose by 3 percent in 1986, by 5 percent to 23,495 in 1989, and by a provisional 6 percent in 1990.1 2 3 4 This unprecedented resurgence of tuberculosis is largely related to the human immunodeficiency virus (HIV) epidemic.1 2 3 Among the diseases associated with HIV infection, tuberculosis is of particular importance because it is contagious by the respiratory route, readily treatable, and potentially preventable with chemoprophylaxis. Physicians must be familiar with the . . .

BACKGROUND: Mortality from all causes is higher for persons with fewer years of education and for blacks, but it is unknown which diseases contribute most to these disparities. METHODS: We estimated cause-specific risks of death from data from the National Health Interview Survey conducted from 1986 through 1994 and from linked vital statistics. Using these risk estimates, we calculated potential years of life lost and potential gains in life expectancy related to specific causes, with stratification according to education level and race. RESULTS: Persons without a high-school education lost 12.8 potential life-years per person in the population, as compared with 3.6 for persons who graduated from high school (ratio, 3.5; P<0.001). Ischemic heart disease contributed most (11.7 percent) to the difference according to education in potential life-years lost (with all cardiovascular diseases accounting for 35.3 percent). All cancers accounted for 26.5 percent, including 7.7 percent due to lung cancer; other lung diseases and pneumonia contributed 10.1 percent of the total, whereas human immunodeficiency virus (HIV) disease accounted for none of the difference according to education. The pattern of disparities according to level of income was similar to that according to level of education. Blacks and whites lost 7.0 and 5.2 potential life-years per person, respectively, as a result of deaths from any cause (ratio, 1.35; P<0.001). Cardiovascular diseases accounted for one third of this disparity, in large part because of hypertension (15.0 percent); HIV disease (11.2 percent) contributed almost as much as ischemic heart disease (5.5 percent), stroke (2.8 percent), and cancer (3.4 percent) combined; trauma and diabetes mellitus accounted for 10.7 percent and 8.5 percent, respectively. CONCLUSIONS: Although many conditions contribute to socioeconomic and racial disparities in potential life-years lost, a few conditions account for most of these disparities - smoking-related diseases in the case of mortality among persons with fewer years of education, and hypertension, HIV, diabetes mellitus, and trauma in the case of mortality among black persons. These findings have important implications for targeting efforts to reduce existing disparities in mortality rates.

Abstract To evaluate the relationship between the clinical presentation of tuberculosis and the CD4 cell count in patients with human immunodeficiency virus (HIV) infection, we evaluated clinical and laboratory features of 97 HIV-infected patients with tuberculosis in whom CD4 cell counts were available. Extrapulmonary tuberculosis was found in 30 (70%) of 43 patients with ⩽ 100 CD4 cells/µL, 10 (50%) of 20 patients with 101 to 200 CD4 cells/µL, seven (44%) of 16 patients with 201 to 300 CD4 cells/µL, and five (28%) of 18 patients with &amp;gt; 300 CD4 cells/µL (p = 0.02). Mycobacteremia was found in 18 (49%) of 37 patients with ⩽ 100 CD4 cells/ µL, three (20%) of 15 patients with 101 to 200 CD4 cells/µL, one (7%) of 15 patients with 201 to 300 CD4 cells/µL, and none of eight patients with &amp;gt; 300 CD4 cells/µL (p = 0.002). Acid-fast smears were more often positive in patients with low CD4 cell counts. Positive tuberculin skin tests were more common in patients with high CD4 counts. On chest roentgenograms, mediastinal adenopathy was noted in 20 (34%) of 58 patients with ⩽ 200 CD4 cells/µL and four (14%) of 29 patients with &amp;gt; 200 CD4 cells/µL (p = 0.04). Pleural effusions were noted in six (10%) of 58 patients with ⩽ 200 CD4 cells/µL and eight (28%) of 29 patients with &amp;gt; 200 CD4 cells/µL (p = 0.04). The CD8 cell counts did not correlate with the manifestations of tuberculosis. We conclude that, in HIV-infected patients, markers of severe tuberculosis, such as mycobacteremia and positive acid-fast smears, are more common in those with low CD4 cell counts. Features dependent on delayed-type hypersensitivity responses, such as positive tuberculin skin tests and tuberculous pleuritis, are more common in patients with higher CD4 cell counts. These findings suggest that CD4 cells play a central role in limiting the severity of tuberculosis.

The incidence and long-term effects of childhood sexual abuse were studied in a clinical sample of 152 adult women. Approximately 44% of female clients presenting to a health center crisis service reported a childhood history of sexual victimization. Prior victimization was associated with increased dissociation, sleep disturbance, tension, sexual problems, and anger on a Crisis Symptom Checklist, as well as greater current use of psychoactive medications, and more frequent histories of suicide attempts, substance addiction, and revictimization. Long-term psychological effects of sexual abuse are interpreted within both a developmental context and in terms of Post Traumatic Stress Disorder. Implications of the current data and related literature for mental health workers are briefly discussed.

We made longitudinal measurements of bone mineral density (BMD) in 139 normal women (ages 20-88 yr) at midradius (99% cortical bone) and lumbar spine (approximately 70% trabecular bone) by single- and dual-photon absorptiometry. BMD was measured 2-6 (median, 3) times over an interval of 0.8-3.4 yr (median, 2.1 yr). For midradius, BMD did not change (+0.48%/yr, NS) before menopause but decreased (-1.01%/yr, P less than 0.001) after menopause. For lumbar spine, there was significant bone loss both before (-1.32%/yr, P less than 0.001) and after (-0.97%/yr, P = 0.006) menopause; these rates did not differ significantly from each other. Our data show that before menopause little, if any, bone is lost from the appendicular skeleton but substantial amounts are lost from the axial skeleton. Thus, factors in addition to estrogen deficiency must contribute to pathogenesis of involutional osteoporosis in women because about half of overall vertebral bone loss occurs premenopausally.

BACKGROUND: Syphilitic ulcers are known to facilitate the transmission of HIV infection, but the effect of syphilis infection on HIV viral loads and CD4 cell counts is poorly understood. METHODS: We abstracted medical records for HIV-infected male syphilis patients seen at three clinics in San Francisco and Los Angeles from January 2001 to April 2003. We compared plasma HIV-RNA levels and CD4 cell counts during syphilis infection with those before syphilis infection and after syphilis treatment, using the Wilcoxon signed rank test. RESULTS: Fifty-two HIV-infected men with primary or secondary syphilis had HIV viral load and CD4 cell count data available for analysis; 30 (58%) were receiving antiretroviral therapy. Viral loads were higher during syphilis compared with pre-syphilis levels by a mean of 0.22 RNA log10 copies/ml (P = 0.02) and were lower by a mean of -0.10 RNA log10 copies/ml (P = 0.52) after syphilis treatment. CD4 cell counts were lower during syphilis infection than before by a mean of -62 cells/mm3 (P = 0.04), and were higher by a mean of 33 cells/mm3 (P = 0.23) after syphilis treatment. Increases in the HIV viral load and reductions in the CD4 cell count were most substantial in men with secondary syphilis and those not receiving antiretroviral therapy. CONCLUSION: Syphilis infection was associated with significant increases in the HIV viral load and significant decreases in the CD4 cell count. The findings underscore the importance of preventing and promptly treating syphilis in HIV-infected individuals.

Tumor responses to programmed cell death protein 1 (PD-1) blockade therapy are mediated by T cells, which we characterized in 102 tumor biopsies obtained from 53 patients treated with pembrolizumab, an antibody to PD-1. Biopsies were dissociated, and single-cell infiltrates were analyzed by multicolor flow cytometry using two computational approaches to resolve the leukocyte phenotypes at the single-cell level. There was a statistically significant increase in the frequency of T cells in patients who responded to therapy. The frequency of intratumoral B cells and monocytic myeloid-derived suppressor cells significantly increased in patients' biopsies taken on treatment. The percentage of cells with a regulatory T-cell phenotype, monocytes, and natural killer cells did not change while on PD-1 blockade therapy. CD8(+) memory T cells were the most prominent phenotype that expanded intratumorally on therapy. However, the frequency of CD4(+) effector memory T cells significantly decreased on treatment, whereas CD4(+) effector T cells significantly increased in nonresponding tumors on therapy. In peripheral blood, an unusual population of blood cells expressing CD56 was detected in two patients with regressing melanoma. In conclusion, PD-1 blockade increases the frequency of T cells, B cells, and myeloid-derived suppressor cells in tumors, with the CD8(+) effector memory T-cell subset being the major T-cell phenotype expanded in patients with a response to therapy.

BACKGROUND: Many smartphone applications (apps) for weight loss are available, but little is known about their effectiveness. OBJECTIVE: To evaluate the effect of introducing primary care patients to a free smartphone app for weight loss. DESIGN: Randomized, controlled trial. (ClinicalTrials.gov: NCT01650337). SETTING: 2 academic primary care clinics. PATIENTS: 212 primary care patients with body mass index of 25 kg/m2 or greater. INTERVENTION: 6 months of usual care without (n = 107) or with (n = 105) assistance in downloading the MyFitnessPal app (MyFitnessPal). MEASUREMENTS: Weight loss at 6 months (primary outcome) and changes in systolic blood pressure and behaviors, frequency of app use, and satisfaction (secondary outcomes). RESULTS: After 6 months, weight change was minimal, with no difference between groups (mean between-group difference, -0.30 kg [95% CI, -1.50 to 0.95 kg]; P = 0.63). Change in systolic blood pressure also did not differ between groups (mean between-group difference, -1.7 mm Hg [CI, -7.1 to 3.8 mm Hg]; P = 0.55). Compared with patients in the control group, those in the intervention group increased use of a personal calorie goal (mean between-group difference, 2.0 d/wk [CI, 1.1 to 2.9 d/wk]; P < 0.001), although other self-reported behaviors did not differ between groups. Most users reported high satisfaction with MyFitnessPal, but logins decreased sharply after the first month. LIMITATIONS: Despite being blinded to the name of the app, 14 control group participants (13%) used MyFitnessPal. In addition, 32% of intervention group participants and 19% of control group participants were lost to follow-up at 6 months. The app was given to patients by research assistants, not by physicians. CONCLUSION: Smartphone apps for weight loss may be useful for persons who are ready to self-monitor calories, but introducing a smartphone app is unlikely to produce substantial weight change for most patients. PRIMARY FUNDING SOURCE: Robert Wood Johnson Foundation Clinical Scholars Program, National Institutes of Health/National Center for Advancing Translational Sciences for the UCLA Clinical and Translational Science Institute, and the Resource Centers for Minority Aging Research Center for Health Improvement of Minority Elderly under the National Institutes of Health/National Institute on Aging.

BACKGROUND: Athletics-associated methicillin-resistant Staphylococcus aureus (MRSA) infections have become a high-profile national problem with substantial morbidity. METHODS: To investigate an MRSA outbreak involving a college football team, we conducted a retrospective cohort study of all 100 players. A case was defined as MRSA cellulitis or skin abscess diagnosed during the period of 6 August (the start of football camp) through 1 October 2003. RESULTS: We identified 10 case patients (2 of whom were hospitalized). The 6 available wound isolates had indistinguishable pulsed-field gel electrophoresis patterns (MRSA strain USA300) and carried the Panton-Valentine leukocidin toxin gene, as determined by polymerase chain reaction. On univariate analysis, infection was associated (P<.05) with player position (relative risk [RR], 17.5 and 11.7 for cornerbacks and wide receivers, respectively), abrasions from artificial grass (i.e., "turf burns"; RR, 7.2), and body shaving (RR, 6.1). Cornerbacks and wide receivers were a subpopulation with frequent direct person-to-person contact with each other during scrimmage play and drills. Three of 4 players with infection at a covered site (hip or thigh) had shaved the affected area, and these infections were also associated with sharing the whirlpool > or =2 times per week (RR, 12.2; 95% confidence interval, 1.4-109.2). Whirlpool water was disinfected with dilute povidone-iodine only and remained unchanged between uses. CONCLUSIONS: MRSA was likely spread predominantly during practice play, with skin breaks facilitating infection. Measures to minimize skin breaks among athletes should be considered, including prevention of turf burns and education regarding the risks of cosmetic body shaving. MRSA-contaminated pool water may have contributed to infections at covered sites, but small numbers limit the strength of this conclusion. Nevertheless, appropriate whirlpool disinfection methods should be promoted among athletic trainers.

PURPOSE: To examine the effect of hospital and surgeon volume on postoperative outcomes and to determine whether hospital or surgeon volume is the stronger predictor. PATIENTS AND METHODS: Using 1997 to 1998 claims data from a national 5% random sample of Medicare beneficiaries, we identified 2,292 men who underwent radical prostatectomy at 1,210 hospitals by 1,788 surgeons. Hospitals were classified as high (> or = 60 per year) or low (< 60 per year) volume according to radical prostatectomy experience over the 2-year period. Surgeons were classified as high (> or = 40 per year) or low (< 40 per year) volume. Multivariate logistic regression was performed to control for patient demographics and comorbidities when assessing the association of hospital and surgeon volume with in-hospital complications, length of stay, and anastomotic stricture rates. In-hospital complications included cardiac, respiratory, vascular, wound, genitourinary, and miscellaneous surgical and medical conditions. RESULTS: High-volume surgeons had half the complication risk (odds ratio [OR] = 0.53; 95% confidence interval [CI], 0.32 to 0.89) and shorter lengths of stay (4.1 v 5.2 days, P =.03) compared with low-volume surgeons. High-volume hospital patients tended to have fewer anastomotic strictures (OR = 0.72; 95% CI, 0.49 to 1.04). Patient age (> or = 75 years) was associated with more complications (OR = 1.9; 95% CI, 1.39 to 2.70), more anastomotic strictures (OR = 2.2; 95% CI, 1.54 to 3.15), and longer hospital stays (parameter estimate = 2.26; 95% CI, 1.75 to 2.77). CONCLUSION: Surgeon volume is inversely related to in-hospital complications and length of stay in men undergoing radical prostatectomy. Hospital volume is not significantly associated with outcomes after adjusting for physician volume. Further study is necessary to elucidate the mechanism of the volume-outcome effect.

OBJECTIVE: To determine the long term effectiveness of collaborative care management for depression in late life. DESIGN: Two arm, randomised, clinical trial; intervention one year and follow-up two years. SETTING: 18 primary care clinics in eight US healthcare organisations. Patients 1801 primary care patients aged 60 and older with major depression, dysthymia, or both. INTERVENTION: Patients were randomly assigned to a 12 month collaborative care intervention (IMPACT) or usual care for depression. Teams including a depression care manager, primary care doctor, and psychiatrist offered education, behavioural activation, antidepressants, a brief, behaviour based psychotherapy (problem solving treatment), and relapse prevention geared to each patient's needs and preferences. MAIN OUTCOME MEASURES: Interviewers, blinded to treatment assignment, conducted interviews in person at baseline and by telephone at each subsequent follow up. They measured depression (SCL-20), overall functional impairment and quality of life (SF-12), physical functioning (PCS-12), depression treatment, and satisfaction with care. RESULTS: IMPACT patients fared significantly (P < 0.05) better than controls regarding continuation of antidepressant treatment, depressive symptoms, remission of depression, physical functioning, quality of life, self efficacy, and satisfaction with care at 18 and 24 months. One year after IMPACT resources were withdrawn, a significant difference in SCL-20 scores (0.23, P < 0.0001) favouring IMPACT patients remained. CONCLUSIONS: Tailored collaborative care actively engages older adults in treatment for depression and delivers substantial and persistent long term benefits. Benefits include less depression, better physical functioning, and an enhanced quality of life. The IMPACT model may show the way to less depression and healthier lives for older adults.

CONTEXT: HIV-positive men and women may have fertility desires and may intend to have children. The extent of these desires and intentions and how they may vary by individuals' social and demographic characteristics and health factors is not well understood. METHODS: Interviews were conducted from September through December 1998 with 1,421 HIV-infected adults who were part of the HIV Cost and Services Utilization Study, a nationally representative probability sample of 2,864 HIV-infected adults who were receiving medical care within the contiguous United States in early 1996. RESULTS: Overall, 28-29% of HIV-infected men and women receiving medical care in the United States desire children in the future. Among those desiring children, 69% of women and 59% of men actually expect to have one or more children in the future. The proportion of HIV-infected women desiring a child in the future is somewhat lower than the overall proportion of U.S. women who desire a child. The fertility desires of HIV-infected individuals do not always agree with those of their partners: As many as 20% of HIV-positive men who desire children have a partner who does not Generally, HIV-positive individuals who desire children are younger, have fewer children and report higher ratings of their physical functioning or overall health than their counterparts who do not desire children, yet desire for future childbearing is not related to measures of HIV progression. HIV-positive individuals who expect children are generally younger and less likely to be married than those who do not. Multivariate analyses indicate that black HIlV-positive individuals are more likely to expect children in the future than are others. While HIV-positive women who already have children are significantly less likely than others both to desire and to expect more births, partner's HIV status has mixed effects: Women whose partner's HIVstatus is known are significantly less likely to desire children but are significantly more likely to expect children in the future than are women whose partner's HIV status is unknown. Moreover, personal health status significantly affects women's desire for children in the future but not men's, while health status more strongly influences men's expectations to have children. CONCLUSIONS: The fact that many HIV-infected adults desire and expect to have children has important implications for the prevention of vertical and heterosexual transmission of HIV, the need for counseling to facilitate informed decision-making about childbearing and childrearing, and the future demand for social services for children born to infected parents.

BACKGROUND: The introduction of universal varicella vaccination in 1995 has substantially reduced varicella-related morbidity and mortality in the United States. However, it remains unclear whether vaccine-induced immunity wanes over time, a condition that may result in increased susceptibility later in life, when the risk of serious complications may be greater than in childhood. METHODS: We examined 10 years (1995 to 2004) of active surveillance data from a sentinel population of 350,000 subjects to determine whether the severity and incidence of breakthrough varicella (with an onset of rash >42 days after vaccination) increased with the time since vaccination. We used multivariate logistic regression to adjust for the year of disease onset (calendar year) and the subject's age at both disease onset and vaccination. RESULTS: A total of 11,356 subjects were reported to have varicella during the surveillance period, of whom 1080 (9.5%) had breakthrough disease. Children between the ages of 8 and 12 years who had been vaccinated at least 5 years previously were significantly more likely to have moderate or severe disease than were those who had been vaccinated less than 5 years previously (risk ratio, 2.6; 95% confidence interval [CI], 1.2 to 5.8). The annual rate of breakthrough varicella significantly increased with the time since vaccination, from 1.6 cases per 1000 person-years (95% CI, 1.2 to 2.0) within 1 year after vaccination to 9.0 per 1000 person-years (95% CI, 6.9 to 11.7) at 5 years and 58.2 per 1000 person-years (95% CI, 36.0 to 94.0) at 9 years. CONCLUSIONS: A second dose of varicella vaccine, now recommended for all children, could improve protection from both primary vaccine failure and waning vaccine-induced immunity.

OBJECTIVES: To examine whether competing subsistence needs and other barriers are associated with poorer access to medical care among persons infected with human immunodeficiency virus (HIV), using self-reported data. DESIGN: Survey of a nationally representative sample of 2,864 adults receiving HIV care. MAIN INDEPENDENT VARIABLES: Going without care because of needing the money for food, clothing, or housing; postponing care because of not having transportation; not being able to get out of work; and being too sick. MAIN OUTCOME MEASURES: Having fewer than three physician visits in the previous 6 months, visiting an emergency room without being hospitalized; never receiving antiretroviral agents, no prophylaxis for Pneumocystis carinii pneumonia in the previous 6 months for persons at risk, and low overall reported access on a six-item scale. RESULTS: More than one third of persons (representing >83,000 persons nationally) went without or postponed care for one of the four reasons we studied. In multiple logistic regression analysis, having any one or more of the four competing needs independent variables was associated with significantly greater odds of visiting an emergency room without hospitalization, never receiving antiretroviral agents, and having low overall reported access. CONCLUSIONS: Competing subsistence needs and other barriers are prevalent among persons receiving care for HIV in the United States, and they act as potent constraints to the receipt of needed medical care. For persons infected with HIV to benefit more fully from recent advances in medical therapy, policy makers may need to address nonmedical needs such as food, clothing, and housing as well as transportation, home care, and employment support.

Adventure travel is becoming more popular, increasing the likelihood of contact with unusual pathogens. We investigated an outbreak of leptospirosis in "Eco-Challenge" multisport race athletes to determine illness etiology and implement public health measures. Of 304 athletes, we contacted 189 (62%) from the United States and 26 other countries. Eighty (42%) athletes met our case definition. Twenty-nine (36%) case-patients were hospitalized; none died. Logistic regression showed swimming in the Segama River (relative risk [RR]=2.0; 95% confidence interval [CI]=1.3 to 3.1) to be an independent risk factor. Twenty-six (68%) of 38 case-patients tested positive for leptospiral antibodies. Taking doxycycline before or during the race was protective (RR=0.4, 95% CI=0.2 to 1.2) for the 20 athletes who reported using it. Increased adventure travel may lead to more frequent exposure to leptospires, and preexposure chemoprophylaxis for leptospirosis (200 mg oral doxycycline/week) may decrease illness risk. Efforts are needed to inform adventure travel participants of unique infections such as leptospirosis.

Objective. In a recent report, the Institute of Medicine (IOM) defines a health service disparity between population groups to be the difference in treatment or access not justified by the differences in health status or preferences of the groups. This paper proposes an implementation of this definition, and applies it to disparities in outpatient mental health care. Data Sources. Health Care for Communities (HCC) reinterviewed 9,585 respondents from the Community Tracking Study in 1997–1998, oversampling individuals with psychological distress, alcohol abuse, drug abuse, or mental health treatment. The HCC is designed to make national estimates of service use. Study Design. Expenditures are modeled using generalized linear models with a log link for quantity and a probit model for any utilization. We adjust for group differences in health status by transforming the entire distribution of health status for minority populations to approximate the white distribution. We compare disparities according to the IOM definition to other methods commonly used to assess health services disparities. Principal Findings. Our method finds significant service disparities between whites and both blacks and Latinos. Estimated disparities from this method exceed those for competing approaches, because of the inclusion of effects of mediating factors (such as income) in the IOM approach. Conclusions. A rigorous definition of disparities is needed to monitor progress against disparities and to compare their magnitude across studies. With such a definition, disparities can be estimated by adjusting for group differences in models for expenditures and access to mental health services.

Trichomonas vaginalis may be emerging as one of the most important cofactors in amplifying HIV transmission, particularly in African-American communities of the United States. In a person co-infected with HIV, the pathology induced by T. vaginalis infection can increase HIV shedding. Trichomonas infection may also act to expand the portal of entry for HIV in an HIV-negative person. Studies from Africa have suggested that T. vaginalis infection may increase the rate of HIV transmission by approximately twofold. Available data indicate that T. vaginalis is highly prevalent among African-Americans in major urban centers of the United States and is often the most common sexually transmitted infection in black women. Even if T. vaginalis increases the risk of HIV transmission by a small amount, this could translate into an important amplifying effect since Trichomonas is so common. Substantial HIV transmission may be attributable to T. vaginalis in African-American communities of the United States.