Particulate matter and manganese exposures in Indianapolis, Indiana.
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The distribution of PM(2.5) and manganese (Mn) personal exposures was determined over a 4-month period in Indianapolis, IN, at a time when the gasoline additive, methylcyclopentadienyl manganese tricarbonyl (MMT), was not being used. The data collection period coincided with the data collection period in the Toronto, ON, study, where MMT had been used as a gasoline additive for over 20 years. The inferential or target population consisted of noninstitutionalized residents of the Indianapolis area during the monitoring period (from May 1996 through August 1996) who were at least 16 years old. The survey instruments used in this study (and also in Toronto) included a household screener form (HSF), a study questionnaire (SQ), and a time and activity questionnaire (TAQ). The SQ was administered to elicit information about the participant and his/her activities, occupation, and surroundings that might be relevant to his/her exposure to particles and Mn. In addition to the personal particulate matter (PM) and elemental 3-day monitoring, 240 participants completed a TAQ on a daily basis during the actual monitoring period. Also, a subset of participants had 3-day outdoor and indoor stationary monitoring at their home (approximately 58 observations), and sampling was conducted at a fixed site (approximately thirty-three 3-day observations). The quality of data was assessed and compared to the Toronto study in terms of linearity of measurement, instrument and method sensitivity, measurement biases, and measurement reproducibility. Twenty-six of the sample filters were subjected to two analyses to characterize the within-laboratory component of precision in terms of relative standard deviations (RSDs). The median RSD for Mn was 8.7%, as compared to 2.2% for Toronto. The quality assurance (QA) laboratory exhibited a clear positive bias relative to the primary laboratory for Al and Ca, but no systematic difference was evident for Mn. A high interlaboratory correlation (>0.99) was also attained for Mn. Mean field blank results for PM and Mn were 0.87 microg/m(3) and 0.71 ng/m(3), respectively, which were comparable to the Toronto study. The median RSDs for colocated fixed site and residential samples ranged from 2.2% to 9.0% for PM and from 8.8% to 15.3% for Mn, which were close to those observed in Toronto. For the PM(10), the 90th percentile indoors was 124 microg/m(3) compared with 54 microg/m(3) outdoors. This pattern was even more pronounced for the PM(2.5) data (90th percentiles of 92 microg/m(3) indoors vs 30 microg/m(3) outdoors). Personal PM(2.5) was somewhat higher than the indoor levels, but the percentiles seemed to follow the more highly skewed pattern of the indoor distribution. This difference was largely due to the presence of some smokers in the sample; e.g., exclusion of smokers led to a personal exposure distribution that was more similar to the outdoor distribution. The estimated 90th percentile for the nonsmokers' personal exposures to PM was 43 microg/m(3) compared with 84 microg/m(3) for the overall population. In general, the Indianapolis PM levels of a given type and cut size were somewhat higher than the levels observed in Toronto, e.g., the median and 90th percentile for the personal PM(2.5) exposures were 23 and 85 microg/m(3), respectively, in Indianapolis, while in Toronto, the corresponding percentiles were 19 and 63 microg/m(3). The cities' distributions of the proportion of the PM(10) mass in the 2.5-microm fraction appeared similar for the residential outdoor data (medians of 0.67 and 0.65 for Indianapolis and Toronto, respectively, and 90th percentiles of 0.83 for both cities). For the indoor data, Indianapolis tended to have a larger portion of the mass in the fine fraction (median of 0.80 compared to 0.70 for Toronto). Unlike the PM, the Indianapolis indoor Mn concentration levels were substantially lower than the outdoor levels for both PM sizes, and the median personal levels for Mn in PM(2.5) appeared to fall between the median indoor and outdoor levels. The personal Mn exposure distributions exhibited more skewness than the indoor or outdoor distributions (e.g., the means for the personal, indoor, and outdoor distributions were 7.5, 2.6, and 3.5 ng/m(3), respectively, while the medians were 2.8, 2.2, and 3.2 ng/m(3), respectively). At least a substantial portion of the high end of the personal exposure distribution appeared to be associated with occupational exposures to Mn. In general, the Mn levels in both cut sizes in Indianapolis were approximately 5 ng/m(3) smaller than those in Toronto (e.g., the estimated median and mean levels for personal Mn exposures in PM(2.5) were 2.8 and 7.5 ng/m(3), respectively, in Indianapolis, but were 8.0 and 13.1 ng/m(3) in Toronto). For the nonoccupational subgroups with no exposure to smoking and no subway riders in the two cities, the medians (2.6 ng/m(3) in Indianapolis and 7.8 ng/m(3) in Toronto) were similar to those for the overall populations, but the means were substantially smaller (3.1 ng/m(3) in Indianapolis and 9.2 ng/m(3) in Toronto). The median proportion of Mn in the fine fraction (relative to the PM(10) Mn) for Indianapolis was 0.39 for outdoors and 0.55 for indoors; these ratios were somewhat smaller than the corresponding Toronto medians (0.52 and 0.73). The study found high correlations for particulates and Mn between personal exposures and indoor concentrations, and between outdoor and fixed site concentrations, and low correlations of personal and indoor levels with outdoor and fixed site levels. The pattern was similar to that observed for Toronto, but slightly more pronounced. The PM(10) Mn concentrations (log scale) generally exhibited stronger associations among these various measures than the PM(2.5) Mn concentrations. Comparisons of the particulate distributions between PTEAM (Riverside, CA) and the Indianapolis and Toronto studies were also made. (+info)
Can guidelines impact the ordering of magnetic resonance imaging studies by primary care providers for low back pain?
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OBJECTIVE: To compare primary care providers' (PCPs') use of lumbar spine magnetic resonance imaging (MRI) studies and surgical referrals for patients with low back pain (LBP) before and after dissemination of the 1994 Agency for Healthcare Policy and Research (AHCPR) LBP guidelines. DESIGN: Retrospective cohort study. PATIENTS AND METHODS: Computerized audits identified patients with LBP evaluated by PCPs in 1994 or 1996 at a university-affiliated Veterans Affairs medical center who had an MRI order and/or a surgical referral. Research assistants recorded patients' demographic characteristics, LBP-related symptoms, and whether the PCP ordered an MRI and/or a surgery consult. For patients referred to surgery without an MRI, subsequent MRI orders by surgeons were recorded. We compared patient characteristics and utilization patterns for 1994 and 1996 and identified independent predictors of MRI orders. RESULTS: PCPs saw 279 and 261 patients with LBP in 1994 and 1996, respectively. An almost identical number of MRIs were ordered in 1994 (99 by PCPs and 42 by surgeons) and 1996 (105 by PCPs and 32 by surgeons). Nearly 50% of patients meeting AHCPR guidelines underwent an MRI in 1994 or 1996. PCPs more frequently ordered a surgery consult in 1994 than in 1996. Providers were less likely to order an MRI for patients with a previous MRI and more likely to order an MRI for those seen in an urgent visit clinic. Neither year nor meeting AHCPR guidelines predicted MRI ordering. CONCLUSIONS: Orders for MRI did not decrease after education on the guidelines. Limiting MRI orders to only "appropriate" patients would not have changed the observed results. (+info)
Condom use as a function of time in new and established adolescent sexual relationships.
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OBJECTIVES: This study sought to describe condom use over time in new and established adolescent relationships. METHODS: The outcome variable was time (in days) until first unprotected coital event. Analyses involved comparisons of Kaplan-Meier survival curves and Cox proportional hazards models. RESULTS: Survival functions for the 2 relationship groups were significantly different. However, by 21 days the curves had converged: 43% of new and 41% of established relationships involved no unprotected coital events. Time to first unprotected coital event was significantly longer in new than in established relationships. CONCLUSIONS: Prolongation of condom use in ongoing relationships may be a useful intervention to prevent sexually transmitted diseases. (+info)
Making better babies: public health and race betterment in Indiana, 1920-1935.
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In 1920, Indiana's Division of Infant and Child Hygiene inaugurated its first Better Babies Contest at the state fair. For the next 12 years, these contests were the centerpiece of a dynamic infant and maternal welfare program that took shape in Indiana during the decade of the federal Sheppard-Towner act. More than just a lively spectacle for fairgoers, these contests brought public health, "race betterment," and animal breeding together in a unique manner. This article describes one of the most popular expressions of public health and race betterment in rural America. It also raises questions about the intersections between hereditarian and medical conceptions of human improvement during the early 20th century, especially with respect to child breeding and rearing. (+info)
Quality of life measurement after stroke: uses and abuses of the SF-36.
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BACKGROUND AND PURPOSE: The Medical Outcomes Study 36-item Short-Form Health Survey (SF-36) is widely used to measure health status after stroke. However, a fundamental assumption for its valid use after stroke has not been comprehensively tested: is it legitimate to generate scores for 8 scales and 2 summary measures using the standard algorithms? We tested this assumption. METHODS: SF-36 data from 177 people after stroke were examined (71% male; mean age, 62). We tested 6 scaling criteria to determine the legitimacy of generating the 8 SF-36 scale scores using Likert's method of summed ratings, and we tested 2 scaling criteria to determine the appropriateness of the standard SF-36 algorithms for weighting and combining scale scores to generate 2 summary measures (physical and mental). RESULTS: Scaling assumptions were fully satisfied for 6 of the 8 scales, but 3 of these 6 scales had notable floor and/or ceiling effects. Assumptions for generating 2 SF-36 summary measures were not satisfied. CONCLUSIONS: In this sample, 5 of the 8 SF-36 scales had limited validity as outcome measures after stroke, and the reporting of physical and mental summary scores was not supported. Results raise questions about the use of the SF-36 in stroke, and the SF-12 that is developed from it, and highlight the importance of testing scaling assumptions when applying existing scales to new populations. (+info)
Acute low back pain self-management intervention for urban primary care patients: rationale, design, and predictors of participation.
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OBJECTIVES: To describe the rationale and design of a self-management program for low-income, urban, primary care patients with acute low back pain. Issues related to recruitment and protocol delivery, and attendance patterns and predictors of program attendance are described. METHODS: Two hundred eleven adult patients (73% female; 60% African American) were recruited from primary care neighborhood health centers. Focus groups were conducted for program development, and participants then completed a baseline interview and were randomized into groups receiving either usual care or a self-management intervention. RESULTS: Twenty-nine percent of the intervention group attended the self-management class. Significant predictors of attendance included being older, reporting less income, and not working for pay. Attendees did not differ from nonattendees on back pain severity, symptoms, health-related quality of life, self-management processes, or satisfaction with care. CONCLUSION: Effective minimal-contact behavioral interventions are needed to reach larger portions of the patient population. (+info)
Prevalence of male and female patterns of early ventricular repolarization in the normal ECG of males and females from childhood to old age.
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OBJECTIVES: This study was designed to establish the cause of electrocardiographic (ECG) pattern differences between genders. BACKGROUND: The male and female patterns of early ventricular repolarization in normal ECGs differ from each other. The male pattern displays a higher J-point amplitude and increased ST angle. The distribution of these patterns between genders has not been studied. METHODS: Normal ECGs of 529 males and 544 females, age 5 to 96 years, were subdivided into nine age groups in each gender. We designated the pattern as female if the J point was <0.1 mV in each of the leads V(1) to V(4), and as male if the J point was > or =0.1 mV and the ST angle > or =20 degrees in at least one of the V(1) to V(4) leads; the pattern was indeterminate if the J point was > or =0.1 mV and the ST angle was <20 degrees. RESULTS: Distribution of patterns was significantly different between genders (p < 0.001). In females, the patterns were distributed similarly from puberty to advanced age with about 80% prevalence of the female pattern. In males, the male pattern prevalence increased at puberty, reached 91% in the age group of 17 to 24 years and declined gradually with advancing age to 14% in the oldest males. The prevalence of indeterminate pattern was about 10% in both genders. Patterns were unchanged in 95% of 493 subjects who had ECGs recorded at separate times or at different heart rates. CONCLUSIONS: Gender differences in early ventricular repolarization were caused by age-dependent changes in prevalence of the male pattern. (+info)
Differences in histoplasmosis in patients with acquired immunodeficiency syndrome in the United States and Brazil.
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Demographic and clinical parameters among patients with acquired immunodeficiency syndrome and histoplasmosis in Brazil and United States were compared. The Brazilian isolates were typed by restriction-fragment length polymorphism analysis and were DNA fingerprinted by random amplification of polymorphic DNA (RAPD)-polymerase chain reaction (PCR). Skin lesions occurred in 66% of Brazilian case patients, compared with 1%-7% of US case patients. Of 21 treated case patients, 4 (19%) died, a rate similar to that of the US case patients (5%-13%). By nuclear gene typing, the Brazilian isolates were equally divided between South American classes 5 and 6, and RAPD-PCR showed 18 distinct genetic fingerprints in 20 isolates. Skin lesions are more common in infection with class 5 or 6 organisms than with class 2 Histoplasma capsulatum. The role of genetic differences in the organism as a cause for the clinical differences requires investigation. (+info)