Race/ethnicity and other risk of factors associated with cryptosporidiosis as an initial AIDS-defining condition in California, 1980-99.

To study whether African-Americans are less likely than whites to present with cryptosporidiosis as an AIDS-defining condition (ADC), a case-control study was conducted using a large, population-based surveillance registry of AIDS patients in California. Data from January 1980 through June 1999 were analysed using risk factor stratification and multivariate logistic regression to evaluate confounding by other risk factors such as gender, injection drug use (IDU), CD4 counts, age and sexual orientation. Cases included 1373 subjects with cryptosporidiosis as an ADC and controls included 97,419 subjects with other ADC. The results indicate a significantly lower risk for presentation with cryptosporidiosis as an ADC among African-Americans compared with whites (OR vs. whites = 0.5, 95% CI 0.4, 0.7). Additionally, there is evidence that heterosexuals are less likely than homosexual/bisexual males to present with cryptosporidiosis (OR = 0.5, 95% CI 0.4, 0.7). Our analyses also suggest a decreasing risk with increasing age. The possibility that there may be biologic factors or differential lifetime exposures that account for the difference between the racial/ethnic groups merits further investigation.

Prevalence of HIV infection, sexually transmitted diseases, and hepatitis and related risk behavior in young women living in low-income neighborhoods of northern California.

OBJECTIVE: To estimate the prevalence of human immunodeficiency virus (HIV) infection, sexually transmitted diseases, and hepatitis and the associated sexual and drug-using behavior among women residing in low-income neighborhoods in 5 northern California counties. METHODS: From April 4, 1996, to January 6, 1998, women aged 18 to 29 years were recruited door-to-door from randomly selected street blocks within 1990 census block groups below the 10th percentile for median household income for each county. RESULTS: Of 24,223 dwellings enumerated, contact was made with residents from 19,546 (80.7%). Within contacted dwellings, 3,560 eligible women were identified and 2,545 enrolled (71.5%). Weighted estimates for disease prevalence were HIV infection, 0.3% (95% confidence interval, 0.1%-0.4%); syphilis, 0.7% (0.3%-1.1%); gonorrhea, 0.8% (0.3%-1.3%); chlamydia, 3.3% (2.4%-4.8%); herpes simplex virus, type 1, 73.7% (71.6%-76.9%); herpes simplex virus, type 2, 34.4% (29.9%-39.0%); hepatitis A, 33.5% (28.3%-38.7%); chronic hepatitis B, 0.8% (0.3%-1.2%); and hepatitis C, 2.5% (1.4%-3. 6%). Condom use at last sexual intercourse with a new partner was reported by 44.0% (33.9%-54.1%). Injection drug use in the last 6 months was reported by 1.8% (1.0%-2.7%). CONCLUSIONS: The Young Women's Survey provided population-based estimates of the prevalence of 8 infectious diseases and related risk behavior within a population for whom data are often difficult to collect. Population-based data are needed for appropriate targeting and planning of primary and secondary disease prevention.

A change-point model for reporting delays under change of AIDS case definition.

Accurate monitoring of disease incidence is of major public health concern. The time delay between diagnosis and the date of reporting creates bias in estimating disease incidence. Changes in case definition are expected to have an impact on the time lag of case reporting. We propose a change-point model for reporting delays in AIDS that takes into account recent changes in the AIDS definition in US and European countries. The model was applied to California AIDS surveillance data and the distribution of reporting delays before and after the recent change of definition in 1993 were analyzed in terms of contributing factors. The overall significance of the model with change-point as compared to the model without change-point indicates that the effect of the 1993 change in definition on the distribution of reporting delays was highly significant (p < 0.0001). Overall, reporting delay of cases initially diagnosed with AIDS-defining diseases before 1993 was shorter compared to after 1993; reporting delay of cases initially diagnosed meeting the 1993 immunologic case definition was shorter than of those initially diagnosed with AIDS-defining diseases. Region of residence, mode of exposure, race/ethnicity and time of diagnosis emerged as the main covariates in the models. The method introduced here applies to current and possible future changes of the AIDS case definition as well as changes in diagnostic criteria or case definition in diseases other than AIDS. We demonstrate that such changes may be accompanied by sizeable changes in the distribution of reporting delays, and thus adjustment for reporting delays must be recalibrated after a change in definition.

Methamphetamine use and sexual and injection risk behaviors among out-of-treatment injection drug users.

Our primary objective was to examine the relationship between methamphetamine use and sexual risk-taking behaviors--number of sexual partners, frequency of sexual behaviors with regular and casual partners, trading money or drugs for sex, and condom use--among male and female out-of-treatment injection drug users (OTIDUs). As a risk group for human immunodeficiency virus (HIV) transmission, we also investigated injection behaviors by methamphetamine use. Data were collected from 1392 OTIDUs within the California counties of Fresno, Sacramento, and San Diego. Excluded from this cross-sectional survey were male OTIDUs engaging in sex with only or mostly men since 1978. In bivariate analyses, we found that male OTIDUs with a history of methamphetamine use had more sex partners and participated in more acts of anal insertive intercourse with casual partners and vaginal intercourse with regular and casual partners than male OTIDUs never using methamphetamines. In addition, a greater percentage of male OTIDUs using methamphetamines reported trading sex for money or drugs. Methamphetamine-using female OTIDUs participated in more acts of vaginal intercourse with regular male sex partners than female OTIDUs never using methamphetamines. By multivariate logistic regression, we found methamphetamine use related to consistent condom use among male OTIDUs and among male sex partners of female OTIDUs. Discriminant function analyses revealed that sexual risk taking could be differentiated by methamphetamine use among male OTIDUs. Methamphetamine use also correlated with using shared needles or syringes among male and female OTIDUs and was related to not always disinfecting used needles or syringes with bleach. Our findings suggest that methamphetamines may contribute to heterosexual HIV transmission.

Prevalence and correlates of hepatitis C virus infection among inmates entering the California correctional system.

To estimate the prevalence and predictors of hepatitis C virus (HCV) infection among inmates, a cross-sectional survey was conducted in 1994 among inmates entering six reception centers of the California Department of Corrections. Discarded serum samples were tested for antibodies to human immunodeficiency virus (HIV), HCV, hepatitis B core, and hepatitis B surface antigen (HBsAg). Of 4,513 inmates in this study, 87.0% were men and 13.0% were women. Among male inmates, 39.4% were anti-HCV-positive; by race/ethnicity, prevalences were highest among whites (49.1%). Among female inmates, 53.5% were anti-HCV-positive; the prevalence was highest among Latinas (69.7%). In addition, rates for HIV were 2.5% for men and 3.1% for women; and for HBsAg, 2.2% (men) and 1.2% (women). These data indicate that HCV infection is common among both men and women entering prison. The high seroprevalence of anti-HCV-positive inmates may reflect an increased prevalence of high-risk behaviors and should be of concern to the communities to which these inmates will be released.

Predictors of failure to return for HIV test result and counseling by test site type.

The objective of this study was to determine the primary predictors of failure to return (FTR) for HIV test results and counseling by test site type from among those variables collected during the pretest, risk assessment session. The study sample consisted of 366,280 clients tested for HIV antibodies over an 18-month period at publicly funded testing sites throughout California. The FTR rate for the entire sample was 16.4%. The most significant predictor of FTR was the site type at which resting took place, with those testing at sexually transmitted disease clinics four times, and mobile testing clients over three times, more likely to fail to return than alternative test site clients. Independent predictors of FTR differed dramatically across the types of testing sites examined. Implications of these results for devising site-specific counseling strategies to reduce FTR are examined and possible effects on FTR of more rapid testing procedures and home testing are considered. Suggestions for future research are outlined.

Association of methamphetamine use during sex with risky sexual behaviors and HIV infection among non-injection drug users.

Morbidity, mortality, and drug treatment data suggest that methamphetamine use is on the rise. Based on research findings of the sexual behaviors of methamphetamine-using injection drug users, we chose to examine the relationship between methamphetamine use during sex and risky sexual behaviors and human immunodeficiency virus (HIV) seropositivity among clients of publicly funded HIV testing sites in California who reported never injecting drugs. We found that among gay, bisexual, and heterosexual men and heterosexual women, users of methamphetamines reported more sexual partners than non-methamphetamine users. Among heterosexuals, a greater percentage of methamphetamine users than nonusers participated in anal intercourse. Methamphetamine use was independently related to decreased condom use during vaginal and anal intercourse, prostitution, and sex with known injection drug users. In addition, methamphetamine users were more likely to have had a sexually transmitted disease. When controlling for race or ethnicity; age; exposure to possibly infected blood or blood products; and the use of cocaine, alcohol, or marijuana during sex, methamphetamine-using bisexual men were more likely to test positive for HIV than those reporting no history of methamphetamine use. Our data suggest that noninjection methamphetamine use is related to increased, unprotected sexual activity and the risk of contracting sexually transmitted diseases, including HIV.

Risk factors for human immunodeficiency virus infection and unprotected anal intercourse among young men who have sex with men.

BACKGROUND AND OBJECTIVES: Few studies concerning human immunodeficiency virus (HIV) and its risk behaviors have been conducted among young men who have sex with men (YMSM). These are important because YMSM will have profound influence on the HIV/acquired immunodeficiency syndrome epidemic. GOALS: To estimate the prevalence of and risk factors associated with HIV infection and recent unprotected anal intercourse (UAI) among YMSM in California. METHODS: Between March and October, 1994, 836 men, 17 to 25 years of age, were surveyed at four California sites. The survey consisted of an interview from a standardized questionnaire and a blood draw for HIV antibody testing. RESULTS: Almost 9.0% tested positive for HIV antibodies, whereas about 36.0% reported recent UAI. Several factors were associated both univariately and multivariately with HIV infection, as well as for recent UAI. CONCLUSIONS: Young men who have sex with men in California continue to engage in behaviors risky for HIV infection. Efforts helping YMSM reduce them should target subgroups having a high HIV seroprevalence or recent UAI prevalence.

Coccidioidomycosis in Tulare County, California, 1991: reemergence of an endemic disease.

In 1991, 1208 cases of coccidioidomycosis were reported to the California Department of Health Services, compared with an annual average of 450 during 1986-90. We conducted a study in Tulare County to define the epidemiology of the disease and identify risk factors for severe disease, focusing on the epidemic period September 1991-December 1991. To identify cases, we used data from the Coccidioidomycosis Serology Laboratory at the University of California, Davis, other laboratories, and the Tulare County Health Department's coccidioidomycosis reporting system. We compared patients who were hospitalized with those who were not to determine risk factors for severe disease. We identified 128 cases of acute coccidioidomycosis diagnosed between 1 September and 31 December 1991 (attack rate 41/100,000); south central Tulare County had the highest attack rate. Thirty-five (27%) case-patients were hospitalized. Male sex (relative risk (RR) 2.5, 95% confidence interval (CI) 1.2-5.0), black people and Asian races (RR 4.8, 95% CI 2.4-9.6), and age > or = 20 years (RR 8.3, 95% CI 1.2-57.4) were univariately significant and remained independently associated with hospitalization in multivariate analysis. The 1991 Tulare County outbreak of coccidioidomycosis was part of a much larger outbreak that began in California during 1991 and continued through 1993. The outbreak was preceded by an unusually rainy spring. Although dust reduction measures during times of increased coccidioidomycosis incidence can help reduce exposure, definitive control awaits the development of a safe, effective vaccine.

Changing trends in the epidemiology of human brucellosis in California from 1973 to 1992: a shift toward foodborne transmission.

From 1973 through 1992, 426 cases of human brucellosis were reported in California, of which 98% were laboratory confirmed. Brucella melitensis was identified in 185 cases (78.7% of the bacteriologically typed cases). Hispanics accounted for 81% of the cases from 1983 to 1992 compared with 65% during the previous decade (P < .01). The population-adjusted average annual incidence was higher in Hispanics, especially in children and teenagers, compared with non-Hispanic whites and African Americans. Slaughterhouse cases decreased from 25% during 1973-1982 to < 3% during the following decade. Changes in case distribution were characterized by a decreasing incidence in the Central Valley and an increasing incidence in the San Francisco Bay area and the southern Coast Range. Hispanics were more likely to report being infected by consumption of milk and cheese in Mexico during 1983-1992 than during the previous 10 years (relative risk, 1.45). Between 1973 and 1992, human brucellosis in California evolved from an occupational to a foodborne illness.

Psychological effects of low exposure to mercury vapor: application of a computer-administered neurobehavioral evaluation system.

A computer-administered neurobehavioral evaluation system in a Chinese language version (NES-C) and a mood inventory of the profile of mood states (POMS) were applied to assess the psychological effects of low-level exposure to mercury vapor in a group of 88 workers (19 males and 69 females, with mean age of 34.2 years) exposed to mercury vapor (average duration of exposure 10.4 years). The well-matched group of 97 nonexposed workers was treated as the control. The intensity of current mercury vapor was relatively mild as reflected by the average level of mercury in the air of the workplace (0.033 mg/m3) and in urine (0.025 mg/liter). The results indicated that the profile of mood states posed was moving to the negative side in Hg-exposed group and most of the NES-C performances, in particular, the mental arithmetic, two-digit search, switching attention, visual choice reaction time, and finger tapping, were also significantly affected compared with those obtained from controls (P < 0.05-0.01). The present study and the previous study on the validation of the system suggest that the NES-C we developed is valid for the neurotoxicity screening among the working population exposed to neurotoxic agents.

Sensitivity and specificity of death certificate diagnoses for dementing illnesses, 1988-1990.

OBJECTIVE: To evaluate the extent to which mortality data, which is often used to track secular trends for specific diseases, underestimates the prevalence of dementia. DESIGN: Retrospective analysis of existing data. SETTING: Department of Mental Health inpatient facilities in South Carolina. SUBJECTS: Inpatients at Department of Mental Health facilities who were listed in the South Carolina Statewide Alzheimer's Disease and Related Disorders Registry and who died between 1988 and 1990 (n = 450). MAIN OUTCOME MEASURES: Sensitivity and specificity of dementia diagnoses on death certificates compared to medical record diagnoses for inpatients with a pre-mortem dementia diagnosis. RESULTS: Twenty-three percent of death certificates contained any dementia diagnosis (104/450). The sensitivity of death certificates varied by type of dementia (28 percent for Alzheimer's disease; 8 percent for multi-infarct dementia) as well as by race, sex, and age. CONCLUSIONS: Mortality statistics substantially underestimate the prevalence of dementing illnesses and do not fully represent the public health burden of dementia.

Estimation of neutron dose equivalent at the mezzanine of the Advanced Light Source and the laboratory boundary using the ORNL program MORSE.

To investigate the radiation effect of neutrons near the Advanced Light Source (ALS) at Lawrence Berkeley Laboratory (LBL) with respect to the neutron dose equivalents in nearby occupied areas and at the site boundary, the neutron transport code MORSE, from Oak Ridge National Laboratory (ORNL), was used. These dose equivalents result from both skyshine neutrons transported by air scattering and direct neutrons penetrating the shielding. The ALS neutron sources are a 50-MeV linear accelerator and its transfer line, a 1.5-GeV booster, a beam extraction line, and a 1.9-GeV storage ring. The most conservative total occupational-dose-equivalent rate in the center of the ALS mezzanine, 39 m from the ALS center, was found to be 1.14 X 10(-3) Sv y-1 per 2000-h "occupational" year, and the total environmental-dose-equivalent rate at the ALS boundary, 125 m from the ALS center, was found to be 3.02 X 10(-4) Sv y-1 per 8760-h calendar year. More realistic dose-equivalent rates, using the nominal (expected) storage-ring current, were calculated to be 1.0 X 10(-4) Sv y-1 and 2.65 X 10(-5) Sv y-1 occupational year and calendar year, respectively, which are much lower than the DOE reporting levels.

Investigation of neutron scattering for a multisphere spectrometer.

Count rates were measured as a function of distance from a planar concrete reflector for a set of eight Bonner-sphere detectors and four isotopic neutron sources. These data can be used to determine the contributions of scattered neutrons to the response of moderated detectors used in environments bounded by concrete. A model based on "images" of the original source can be developed to produce an equation that describes the data well, if the strengths of the image sources can be treated as variable parameters. Values of the parameters appearing in the equations are given based on least-squares analysis of the experimental results.