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Biomedical subjects

D M Murray

Publications and source records attributed to D M Murray.

At least 37 records · Page 2Linked to original sources
PubMed2000

Socioeconomic status, ethnicity, and environmental tobacco exposure among non-smoking females.

This study examined the relationship between socioeconomic status (SES) and environmental tobacco smoke (ETS) exposure among non-smoking females, determined which SES variable(s) were most strongly associated with ETS exposure, and examined whether the relationship between SES and ETS exposure was the same for Blacks and Whites. Participants were 404 never-smoker females recruited in the community. Independent variables included income, education, occupation, median income within zip code of participants' residence, and ethnicity. Number of days per week exposed to ETS in the past year was the dependent variable. There was a significant correlation between CO levels (parts per million, ppm) and self-reported ETS exposure (r = 0.22, p < 0.001). The mean CO level exposure was 1.81 +/- 1.19 ppm, and the mean number of days per week of ETS exposure was 4.72 +/- 4.71. The most frequent source of ETS exposure was at public places (64.4%). Although Blacks tended to report higher ETS exposure than Whites (p = 0.08), this tendency disappeared when SES indicators were entered in the model. Correlations among SES indicators were either non-significant or very modest suggesting that different SES indicators may not measure the same construct. Education was the only SES variable that was significantly associated with ETS exposure in this population. The relationship between SES and ETS exposure was similar for both Blacks and Whites. These findings suggest that education may be the most important factor to be considered when designing interventions to decrease ETS exposure among young non-smoking females (e.g., public education of the hazards of ETS exposure and awareness of existing tobacco-control laws and regulations).

Adolescent↗
PubMed2000

Impact of community intervention to reduce patient delay time on use of reperfusion therapy for acute myocardial infarction: rapid early action for coronary treatment (REACT) trial. REACT Study Group.

BACKGROUND: Reperfusion therapy for acute myocardial infarction (AMI) is a time-dependent intervention that can reduce infarct-related morbidity and mortality. Out-of-hospital patient delay from symptom onset until emergency department (ED) presentation may reduce the expected benefit of reperfusion therapy. OBJECTIVE: To determine the impact of a community educational intervention to reduce patient delay time on the use of reperfusion therapy for AMI. METHODS: This was a randomized, controlled community-based trial to enhance patient recognition of AMI symptoms and encourage early ED presentation with resultant increased reperfusion therapy rates for AMI. The study took place in 44 hospitals in 20 pair-matched communities in five U.S. geographic regions. Eligible study subjects were non-institutionalized patients without chest injury (aged > or =30 years) who were admitted to participating hospitals and who received a hospital discharge diagnosis of AMI (ICD 410); n = 4,885. For outcome assessment, patients were excluded if they were without survival data (n = 402), enrolled in thrombolytic trials (n = 61), receiving reperfusion therapy >12 hours after ED arrival (n = 628), or missing symptom onset or reperfusion times (n = 781). The applied intervention was an educational program targeting community organizations and the general public, high-risk patients, and health professionals in target communities. The primary outcome was a change in the proportion of AMI patients receiving early reperfusion therapy (i.e., within one hour of ED arrival or within six hours of symptom onset). Trends in reperfusion therapy rates were determined after adjustment for patient demographics, presenting blood pressure, cardiac history, and insurance status. Four-month baseline was compared with the 18-month intervention period. RESULTS: Of 3,013 selected AMI patients, 40% received reperfusion therapy. Eighteen percent received therapy within one hour of ED arrival (46% of treated patients), and 32% within six hours of symptom onset (80% of treated patients). No significant difference in the trends in reperfusion therapy rates was attributable to the intervention, although increases in early reperfusion therapy rates were noted during the first six months of the intervention. A significant association of early reperfusion therapy use with ambulance use was identified. CONCLUSIONS: Community-wide educational efforts to enhance patient response to AMI symptoms may not translate into sustained changes in reperfusion practices. However, an increased odds for early reperfusion therapy use during the initiation of the intervention and the association of early therapy with ambulance use suggest that reperfusion therapy rates can be enhanced.

Adult↗
PubMed2000

Components of variance in a group-randomized trial analysed via a random-coefficients model: the Rapid Early Action for Coronary Treatment (REACT) trial.

Rapid Early Action for Coronary Treatment (REACT) was a multisite trial testing a community intervention to reduce the delay between onset of symptoms of acute myocardial infarction (MI) and patients' arrival at a hospital emergency department. The study employed a group-randomized trial design, with ten communities randomized from within matched pairs to each of two conditions. REACT also employed continuous data collection, based on surveillance of heart attack patients in community emergency departments. They analysed their data by comparing the mean slope for delay time in the ten intervention communities to the mean slope estimated in the ten control communities. Because no estimates of slope variation were available a priori, REACT was sized using approximations based on more traditional designs. In this paper, we present the slope and residual error variances as estimated from the REACT data and examine their influence on the power of the trial post hoc. We also examine the power of the trial as it would have been given a more traditional pretest-post-test design with analysis via a comparison of the net difference in condition means pretest vs post-test.

Ambulances↗
PubMed2000

Communities mobilizing for change on alcohol: outcomes from a randomized community trial.

OBJECTIVE: Communities Mobilizing for Change on Alcohol (CMCA) was a randomized 15-community trial of a community organizing intervention designed to reduce the accessibility of alcoholic beverages to youths under the legal drinking age. METHOD: Data were collected at baseline before random assignment of communities to intervention or control condition, and again at follow-up after a 2.5-year intervention. Data collection included in-school surveys of twelfth graders, telephone surveys of 18- to 20-year-olds and alcohol merchants, and direct testing of the propensity of alcohol outlets to sell to young buyers. Analyses were based on mixed-model regression, used the community as the unit of assignment, took into account the nesting of individual respondents or alcohol outlets within each community, and controlled for relevant covariates. RESULTS: Results show that the CMCA intervention significantly and favorably affected both the behavior of 18- to 20-year-olds (effect size = 0.76, p<.01) and the practices of on-sale alcohol establishments (effect size = 1.18, p<.05), may have favorably affected the practices of off-sale alcohol establishments (effect size = 0.32, p = .08), but had little effect on younger adolescents. Alcohol merchants appear to have increased age-identification checking and reduced propensity to sell to minors. Eighteen- to 20-year-olds reduced their propensity to provide alcohol to other teens and were less likely to try to buy alcohol, drink in a bar or consume alcohol. CONCLUSIONS: Community organizing is a useful intervention approach for mobilizing communities for institutional and policy change to improve the health of the population.

Adolescent↗
PubMed2000

Intraclass correlations from a community-based alcohol prevention study: the effect of repeat observations on the same communities.

OBJECTIVE: School- and community-based alcohol prevention programs are often evaluated using a group-randomized trial (GRT) design with a single pretest and a single posttest survey. To size such studies properly, investigators need accurate estimates of the variance and intraclass correlation that will be operative in their analyses. Until recently, the only available estimates were based on cross-sectional analyses. A recent report suggests that values from cross-sectional analyses may overestimate the intraclass correlation operative in pretest-posttest analyses. The purpose of this article is to review these issues, present estimates of intraclass correlation for a variety of alcohol-related endpoints based on cross-sectional analyses and to compare those estimates to estimates based on pretest-posttest analyses. We will also show how these estimates can be used to establish optimal sample sizes for GRTs to evaluate school- and community-based alcohol prevention programs. METHOD: Data were collected from 18 to 20 year olds and high-school seniors as part of an alcohol prevention effort employing a group-randomized trial design with a single pretest and a single posttest survey. Data were analyzed via mixed-model regression methods to estimate components of variance. Those components were then used to compute the intraclass correlations operative in both cross-sectional analyses and in pretest-posttest analyses. RESULTS: Results indicate that intraclass correlations operative in pretest-posttest analyses are much smaller than are those operative in cross-sectional analyses. CONCLUSIONS: Our findings indicate that future alcohol-prevention studies employing a group-randomized trial design with a single pretest and single posttest survey may not need to be as large as previously suggested by intraclass correlation estimates based on cross-sectional data. This holds true even if they are analyzed to reflect the extra variation typical of group-randomized trials.

Adolescent↗
PubMed2000

Understanding condom use among heroin addicts in methadone maintenance using the information-motivation-behavioral skills model.

The current study represents the application of a health behavior model to account for unsafe sexual behavior (as opposed to unsafe needle use) among heroin addicts in methadone treatment. The Information-Motivation-Behavioral Skills (IMB) model of HIV preventive behavior asserts that HIV prevention information, motivation, and behavioral skills are fundamental determinants of HIV preventive behavior. Participants (N = 156 heroin-addicted individuals in methadone treatment) completed assessments of their levels of HIV prevention information, motivation, behavioral skills, and safer sexual behavior. Overall measures of fit generated via structural equation modeling indicate that the IMB model adequately fits the data obtained. The constructs of the model accounted for a substantial proportion of the variance in safer sexual behavior, and tests of parameter estimates indicate that while information and motivation had direct and reliable associations with safer sexual behavior in this population, behavioral skills did not. Discussion focuses on the primary roles of HIV prevention information and motivation as determinants of safer sexual behavior in this population, on the lack of a significant contribution of HIV prevention behavioral skills, and on the implications for intervention of this pattern of findings.

Adult↗
PubMed1999

Weight-related attitudes and behaviors in fourth grade American Indian children.

OBJECTIVE: American Indian children have a high prevalence of obesity, yet little is known about weight-related attitudes and the prevalence of dieting in this population. This study assessed weight concerns, body size perceptions, weight reduction attempts, and weight loss methods in fourth grade American Indian children. RESEARCH METHODS AND PROCEDURES: Participants (n = 304) attended one of eight schools in the Pathways Feasibility Study. Question and answer choices were read to children by trained staff, and children marked their own answers. RESULTS: Thirty-eight percent of the children reported that they had tried to lose weight. The most common strategy for weight reduction was exercising more. Girls were more likely than boys to be dissatisfied with their body size (48% of girls vs. 34% of boys desired a slimmer body size; 22% of girls vs. 15% of boys desired a larger body size; p<0.001). Children who had tried to lose weight were more likely to indicate that the size they most desired and the most healthy size were smaller than their perceived size (p<0.001). Children who reported trying to lose weight were also more likely to want to be skinnier and to be unhappy about their weight than were children who did not report trying to lose weight (p<0.001 for both). DISCUSSION: We conclude that weight loss attempts and weight-related concerns are prevalent in American Indian children at a young age.

Arizona↗
PubMed1999

The paucity of effects in community trials: is secular trend the culprit?

BACKGROUND: The most recent major U.S. trials that evaluated community-level programs to influence risk factors and health behaviors identified secular trends in the risk factors and health behaviors among the factors that might have limited community-level effects. The research reported in this paper uses data from one of the trials to examine the secular trend explanation directly. METHODS: Data from the 22-community Community Intervention Trial for Smoking Cessation (COMMIT) were analyzed to test a hypothesis based on secular trend reasoning: program effects for smoking prevalence were larger for treatment communities matched to control communities with small declines in smoking than in treatment communities matched to control communities with larger declines in smoking. RESULTS: Consistent with the secular trend explanation, program effects were larger when control communities had relatively small declines in smoking prevalence. CONCLUSIONS: The findings suggest that secular trends masked community-level program effects in COMMIT.

Canada↗
PubMed1999

Age of initiation, smoking patterns, and risk in a population of working adults.

BACKGROUND: Early age of initiation is a significant risk factor for long-term dependent smoking and may also relate to other unhealthy behaviors and increased likelihood of illness, independent of duration of smoking. METHODS: The current study assessed age of initiation in relation to cigarette dependence, interest in quitting, social environment pertaining to smoking, behavioral risk factors, and current health problems. Subjects were 2120 current daily smokers in 24 worksites in the Minneapolis/St. Paul, Minnesota, metropolitan area. RESULTS: Findings were surprisingly consistent with early age of initiation predicting more dependent smoking, less interest and confidence in ability to quit, poorer diet, less use of seat belts, more illness and hospitalization, and greater likelihood of smoking among partner/spouse, friends, and co-workers. CONCLUSIONS: The overall strength of the findings was unexpected. Early initiation of regular smoking predicted a significant constellation of risk factors throughout adulthood. Interventions that significantly delay smoking onset, even in the absence of permanent prevention, could have important public health implications.

Adolescent↗
PubMed1999

Design and statistical analysis for the Pathways study.

We report the design, rationale, and statistical procedures used in Pathways, a randomized, school-based intervention for the primary prevention of obesity in American Indian children. The intervention, which is now being implemented in 7 American Indian communities around the country, includes a health-promotion curriculum, a physical education program, a school meal program, and a family involvement component. Forty-one schools serving American Indian children were randomly assigned to be either intervention or control groups. The intervention will begin in the third grade and continue through the end of the fifth grade. Efficacy of intervention will be assessed by differences in mean percentage body fat, calculated by a prediction equation, between intervention and control schools at the end of the fifth grade. Power computations indicate that the study has power to detect a mean difference of 2.8% in body fat. Data analysis will use intention-to-treat concepts and the mixed linear model. The study will be completed in 2000.

Analysis of Variance↗
PubMed1999

Process evaluation in a multisite, primary obesity-prevention trial in American Indian schoolchildren.

We describe the development, implementation, and use of the process evaluation component of a multisite, primary obesity prevention trial for American Indian schoolchildren. We describe the development and pilot testing of the instruments, provide some examples of the criteria for instrument selection, and provide examples of how process evaluation results were used to document and refine intervention components. The theoretical and applied framework of the process evaluation was based on diffusion theory, social learning theory, and the desire for triangulation of multiple modes of data collection. The primary objectives of the process evaluation were to systematically document the training process, content, and implementation of 4 components of the intervention. The process evaluation was developed and implemented collaboratively so that it met the needs of both the evaluators and those who would be implementing the intervention components. Process evaluation results revealed that observation and structured interviews provided the most informative data; however, these methods were the most expensive and time consuming and required the highest level of skill to undertake. Although the literature is full of idealism regarding the uses of process evaluation for formative and summative purposes, in reality, many persons are sensitive to having their work evaluated in such an in-depth, context-based manner as is described. For this reason, use of structured, quantitative, highly objective tools may be more effective than qualitative methods, which appear to be more dependent on the skills and biases of the researcher and the context in which they are used.

Asian People↗
PubMed1998

Analysis of data from group-randomized trials with repeat observations on the same groups.

This study used Monte Carlo simulations to evaluate the performance of alternative models for the analysis of group-randomized trials having more than two time intervals for data collection. The major distinction among the models tested was the sampling variance of the intervention effect. In the mixed-model ANOVA, the sampling variance of the intervention effect is based on the variance among group x time-interval means. In the random coefficients model, the sampling variance of the intervention effect is based on the variance among the group-specific slopes. These models are equivalent when the design includes only two time intervals, but not when there are more than two time intervals. The results indicate that the mixed-model ANOVA yields unbiased estimates of sampling variation and nominal type I error rates when the group-specific time trends are homogenous. However, when the group-specific time trends are heterogeneous, the mixed-model ANOVA yields downwardly biased estimates of sampling variance and inflated type I error rates. In contrast, the random coefficients model yields unbiased estimates of sampling variance and the nominal type I error rate regardless of the pattern among the groups. We discuss implications for the analysis of group-randomized trials with more than two time intervals.

Analysis of Variance↗
PubMed1998

Relations of cigarette smoking and dietary antioxidants with placental calcification.

Associations between maternal cigarette smoking and accelerated placental maturation measured as tissue calcification have been reported. The authors sought to address whether intakes of the dietary antioxidants, vitamin C, alpha-tocopherol, and beta-carotene, were related to placental calcification of the maternal surface and villi in a cohort of smokers and nonsmokers at risk for delivering small-for-gestational age infants. Gross and histologic examination of placentas were used to determine calcification at the surface (n = 1,213) and villus sites (n = 730), respectively, in a prospective study of black and white women who delivered singleton births between December 1985 and October 1988 at the University of Alabama at Birmingham Hospital in Birmingham, Alabama. Controlling for race and gestational age, likelihood of surface and villus calcification increased as smoking levels increased. Significant reductions in villus calcification were related to alpha-tocopherol intake after controlling for smoking and gestation while intakes of beta-carotene and vitamin C were related to significant reductions in calcification for black but not white women. Surface calcification was not found to be related to antioxidant intake. The authors' findings confirm a pathologic relation between smoking and placental calcification and suggest that dietary antioxidants may reduce villus calcification.

Antioxidants↗
PubMed1998

Comparison of 3 methods for counting fruits and vegetables for fourth-grade students in the Minnesota 5 A Day Power Plus Program.

OBJECTIVE: To compare fruit and vegetable servings calculated from 24-hour dietary recall data using 3 methods: a counting scheme developed for the 5 A Day for Better Health study, a method developed by the University of Minnesota Cancer Prevention Research Unit to quantify total consumption of fruits and vegetables, and a counting scheme based on the US Food and Drug Administration's Reference Amounts. The counting methods differ by food items counted and by serving sizes for those items. SUBJECTS/SETTING: Record-assisted 24-hour dietary recalls were collected from 617 randomly selected fourth-grade students (317 girls, 300 boys) from 23 schools in St Paul, Minn, participating in the Minnesota 5 A Day Power Plus Program. DESIGN: The dietary recalls were analyzed using the Minnesota Nutrition Data System (version 2.6/8a/23). Total servings of fruits and vegetables, servings of vegetables, servings of fruits plus juices, servings of fruit juice, and servings of fruit excluding juice were tallied using each counting method. STATISTICAL ANALYSES: A mixed-model Poisson regression analysis was conducted to compare numbers of servings calculated using the 3 methods. RESULTS: Counts of daily total fruits and vegetables averaged 3.9 servings with the 5 A Day method, 4.1 servings using US Food and Drug Administration Reference Amounts, and 5.1 servings with the Minnesota Cancer Prevention Research Unit method (P < .0001). APPLICATIONS: Because the different counting methods yield different tallies of fruit and vegetable intake, it is important for researchers and practitioners interested in fruit and vegetable consumption to be clear about their uses of the data before choosing a counting scheme.

Child↗
PubMed1998

Statistical design of REACT (Rapid Early Action for Coronary Treatment), a multisite community trial with continual data collection.

Unusual problems in statistical design were faced by Rapid Early Action for Coronary Treatment (REACT), a multisite trial testing a community intervention to reduce the delay between onset of symptoms of acute myocardial infarction (MI) and patients' arrival at a hospital emergency department. In 20 pair-matched U.S. communities, hospital staff members recorded delay time throughout a 4-month baseline period and the subsequent 18-month intervention period, during which one randomly selected community of each pair received a campaign of public and professional education. To exploit the continual nature of its data-collection protocol, REACT estimated the trend of delay time separately in each community by linear regression, adjusting for age, sex, and history of MI, and compared the ten adjusted slopes from intervention communities with those from control communities by a paired t-test. Power calculations based on the analytical model showed that with K=600-800 cases per community, REACT would have 80% power to demonstrate a differential reduction of 30 min in mean delay time between intervention and control communities, as well as effects on a variety of secondary outcomes. Sensitivity analysis confirmed that the number of communities was optimal within constraints of funding and that the detectable effect depended weakly on the effectiveness of matching but strongly on K, helping the investigators set operational priorities. The methodologic strategy developed for REACT should prove useful in the design of similar trials in the future.

Emergencies↗
PubMed1998

All that wheezes is not asthma. Paradoxical vocal cord movement presenting as severe acute asthma requiring ventilatory support.

A 23-year-old female presented with an acute exacerbation of her asthma, for which she required ventilatory support. Her wheeze disappeared immediately following tracheal intubation and ventilatory support was achieved with low airway pressures. We believe that the diagnosis of status asthmaticus was incorrect and that the patient was suffering from vocal cord dysfunction. We review reports of this condition and suggest that, in asthma, the expiratory flow limitation due to paradoxical vocal cord movement may be an appropriate physiological response to improve overall airflow. However, this glottic narrowing may cause respiratory distress of its own accord. Our observations suggest a simple approach to the diagnosis and management of patients whose respiratory distress may be caused by paradoxical vocal cord movement. Immediate relief of 'bronchospasm' in an asthmatic following tracheal intubation may establish the correct diagnosis. This has important implications for the management of these patients in the intensive care unit.

Adult↗