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PubMed2003

Use of critical pathways to improve efficiency: a cautionary tale.

BACKGROUND: Critical pathways are healthcare management plans that specify patient goals and the sequence and timing of actions necessary to achieve these goals with optimal efficiency. More than 80% of hospitals in the United States use critical pathways for at least some of their patients. Unfortunately, critical pathway effectiveness in improving clinical efficiency is unclear. OBJECTIVES: To assess whether critical pathways have been successful in reducing patient length of stay (LOS) and resource utilization in our tertiary-care academic medical center. STUDY DESIGN: A before-and-after observational study using multivariate linear regression analyses. METHODS: We identified all critical pathways initiated in our medical center between 1993 and 1996 in which at least 50 adult patients would be evaluated in the year preceding and succeeding pathway implementation; 13 pathways satisfied these inclusion criteria. Using a before-and-after design, multivariate linear regression was used to evaluate each pathway's effect on average monthly LOS and resource utilization after adjusting for case mix and secular trends. RESULTS: Three of the 13 pathways were associated with a statistically significant immediate decrease in inpatient LOS: acute myocardial infarction (20.7% decrease; P = .001), cesarean section (14.6% decrease; P = .03), and kidney transplantation (24.5% decrease; P = .003). Only 1 pathway, percutaneous transluminal coronary angioplasty (PTCA), produced a statistically significant decrease in LOS slope (a decrease of 5.2% per month; P = .001). Two pathways were accompanied by a statistically significant immediate reduction in ancillary resource utilization: kidney transplantation (26.4% decrease; P = .001) and community-acquired pneumonia (21.8% decrease; P = .002). Only the PTCA pathway produced a statistically significant decrease in resource utilization slope during the 12-month follow-up period (a decrease of 8.4% per month; P < .001). CONCLUSIONS: Although some pathways did reduce LOS or resource utilization or both, most pathways reduced neither. Because substantial resources must be expended on pathway development, implementation, and maintenance, future efforts should be placed on further evaluating the effectiveness of critical pathways and understanding the reasons behind their success or failure before additional resources are consumed for this management strategy.

Critical Pathways↗

PubMed2001

Predictors for development of hyperuricemia: an 8-year longitudinal study in middle-aged Japanese men.

To identify the factors responsible for increases in serum uric acid (SUA), a cohort of 1,312 hyperuricemia-free (SUA < 7.5 mg/dL and no medication for hyperuricemia or hypertension) male office workers aged 30 to 52 years were examined annually for 8 successive years. Subjects who were found to have become hyperuricemic (SUA > or = 7.5 mg/dL) or who started medication for hyperuricemia during repeat surveys were defined as incidence cases. The SUA trend was also examined in 1,062 subjects for whom 9 consecutive SUA values were available and who did not start medication for hyperuricemia or hypertension during the observation period. Multivariate analyses, excluding the baseline SUA level as a factor in the Cox proportional-hazards model, indicated that age (negative), body mass index (BMI), log triglyceride level, hemoglobin A(1c) (HbA(1c)) level (negative), white blood cell count, and alcohol intake at study entry were significantly associated with the incidence of hyperuricemia. In the model including the baseline SUA level, baseline SUA level was the strongest factor for the incidence of hyperuricemia, and BMI, white blood cell count, and alcohol intake at study entry remained as independent factors. From stepwise linear regression analyses for SUA slope, excluding the baseline SUA level as a factor, significant correlates with SUA slope were, in order of their relative importance, slopes of BMI, HbA(1c) (negative), blood urea nitrogen, log triglyceride level, total protein, and baseline levels of hematocrit (negative), white blood cells, and HbA(1c) (negative). In stepwise linear regression analyses, including the baseline SUA level as a factor, SUA level (negative) and alcohol intake at study entry emerged as significant factors for SUA slope. The cumulative percentage of variation for SUA slope was 25.6%. In conclusion, obesity, alcohol intake, and multimetabolic disorders were determined to be independent predictors for the development of hyperuricemia. In addition, the white blood cell level may be a contributory factor.

Adult↗

PubMed2001

Impact of clinical volume on scholarly activity in an academic children's hospital: trends, implications, and possible solutions.

PURPOSE: To evaluate the effect of changes in clinical volume on scholarly activities in an academic pediatric radiology department. METHODS: For each academic year from 1995 to 2000 we queried the departmental radiology information system for clinical examination volume and work complexity expressed in work relative value units (RVU) per full-time equivalent (FTE) radiologist. Publication activity by faculty and fellows was assessed by an electronic (Medline) search for all peer-reviewed articles. Departmental presentations at annual meetings of four major radiological societies were determined from published proceedings. The relationship between scholarly activity and clinical volumes was assessed by linear regression. RESULTS: Over the 6-year study period, the number of clinical exams per FTE radiologist increased by 17 % (P < 0.05) and the number of RVUs per FTE radiologist increased by 46 % (P < 0.02). During the same period, the number of peer-reviewed publications per FTE radiologist decreased by 69 % (P < 0.01 by linear regression), while number of presentations at national meetings dropped by 16 % (P = NS). Number of clinical examinations and RVU per FTE were both strong predictors of decreasing publication rate (r = -1, P < 0.04), but not of academic presentations at national meetings. There was no correlation between clinical and academic productivity for individual faculty in the final year of the study (r < 0.01, P = NS). CONCLUSIONS: Increases in clinical workload have negatively affected the academic productivity of pediatric radiologists at a large children's hospital.

Academic Medical Centers↗

PubMed1999

A combined method for estimating ventilatory threshold.

BACKGROUND: The aims of this study were to compare two new methods (Dmax and CUSUM) for determination of the ventilatory threshold and to examine the consequences of estimation by application of these methods in combination. METHODS EXPERIMENTAL DESIGN: a comparative design was used. SETTING: the study was performed in the Exercise Physiology Laboratory in the Faculty of Medicine, Selçuk University. PARTICIPANTS: thirty-two untrained males (20.6 +/- 1.2 yrs) performed an incremental exercise test on a cycle ergometer. INTERVENTIONS: there is no intervention. MEASURES: ventilatory and gas exchange variables were measured breath-by-breath. The ventilatory thresholds were detected by conventional linear regression, CUSUM, Dmax and combined CUSUM-Dmax methods. RESULTS: The ventilatory thresholds determined by Dmax method gave the highest r-values compared to the criterion method. There was no statistical difference between thresholds determined by all methods or by the same method using different variables. Ventilatory thresholds could not be determined by the conventional linear regression method in three subjects but were determined in all subjects by the other three methods. CONCLUSIONS: Although all methods presented in this study can be used in the determination of ventilatory threshold, the Dmax method was found to be the most valid one. When using the CUSUM method, combining it with the Dmax method increases the validity of the measurement.

Adult↗

PubMedDate not supplied

Evaluation of the financial impact of ketorolac tromethamine therapy in hospitalized patients.

This retrospective cohort study aimed to determine the resource utilization and cost consequences of ketorolac tromethamine in postoperative pain management in a variety of clinical circumstances. All patients were treated at LDS Hospital, Salt Lake City, Utah, a 520-bed teaching hospital. A long-term archive of clinical and financial data from a computerized hospital information system was searched for patients with specified primary International Classification of Diseases, 9th Revision, Clinical Modification discharge diagnoses treated from June 1, 1990, to July 1, 1992, who received ketorolac (n = 229). These patients were matched with cohort patients (n = 821) treated from July 1, 1989, to May 31, 1990, who did not receive ketorolac. The archive contained information on ketorolac exposure as well as concurrent drug therapy and adverse drug events that had been prospectively evaluated during hospitalization throughout the study and cohort periods. Detailed costs were available for each patient. The study examined attributable differences in lengths of stay and total costs using linear regression modeling. We found a statistically significant attributable decreased length of stay for ketorolac patients of 1.15 days. Case patients also had reduced usage of narcotic drugs (4.39 fewer doses than cohorts and 15.6 hours shorter duration of narcotics than cohorts), reduced use of antiemetic and antipruritic medications, and reduced numbers of adverse events. Linear regression modeling showed that ketorolac use was significantly related to reduced cost using inflation-adjusted dollars. We believe that ketorolac has significant cost advantages over opiate analgesics because of its narcotic-sparing effects. Advantages of ketorolac use include reduced rates of adverse drug events, reduced lengths of stay, especially for orthopedic surgery, and reduced overall hospital costs for diagnosis-related groups associated with cholecystectomy.

Adult↗

PubMed1991

Influence of method of model fitting and gender on estimated parameters for the relationship between starvation heat production and body size in the domestic fowl.

The relationship between starvation heat production (SHP) in kJ/d and body weight (W) in kg for domestic fowl was examined with compiled calorimetric data for 294 fowls (Johnson and Farrell, 1985). Linear regression analyses using ordinary least squares methods were performed before and after transformation of the data to a logarithmic scale (base = 10). Coefficients of determination (R2) were similar for untransformed and log-transformed data (R2's = .56 and .53, respectively). The slopes for untransformed data of males and females were different (P less than 0.033). When the model parameters for: SHP = b0 Wb1 were derived from log-transformed data, there were no significant differences in exponents for males vs. females (P greater than .95). However, when the coefficients were estimated using non-linear regression techniques, a difference was detected at the level of P = 0.072. It was determined that there is no advantage in describing the relationship of SHP as a non-linear function of W, nor is it appropriate to express physiological variables as a ratio of weight raised to some mass exponent without statistical justification. Using W or W2 as a covariable for the statistical analysis of physiological data would produce equally acceptable determinations of significance.

Animals↗

PubMed1996

Phase I pharmacokinetics and limited sampling strategies for the bioreductive alkylating drug EO9. EORTC Early Clinical Trials Group.

EO9 is a synthetic indoloquinone which was designed to undergo redox cycling and formation of alkylating intermediates under bioreductive conditions. As part of a phase I clinical trial, EO9 plasma disposition was evaluated in 20 patients receiving 2.7-15 mg/m2i.v. weekly for 3 weeks. Pharmacokinetic studies were performed with the first and third dose of therapy and nine blood samples were obtained over 30 min postinfusion. Plasma EO9 was detected using HPLC UV and the disposition described by a two-compartment model. Wide variability in EO9 pharmacokinetics was observed. EO9 was rapidly eliminated from plasma with a median systemic clearance of 3.5 l/min/m2 (range 1.2-9.8), apparent volume of distribution of 6.2 l/m2 (1.0-34.9) and t 1/2 beta of 10.1 min (2.2-63.0). Substantial intrapatient variability was observed for all pharmacokinetic parameters. Linear regression and Bayesian methods were developed and validated for estimation of EO9 plasma AUC using up to three samples postinfusion. The use of two or three plasma samples provided precise estimation with acceptable prediction bias. In addition, a Bayesian algorithm offered more robust estimation of AUC and is preferable to linear regression models for future EO9 population pharmacokinetic analysis.

Adult↗

PubMed1998

Wear in retrieved acetabular components: effect of femoral head radius and patient parameters.

Forty-seven explanted Porous Coated Anatomic (PCA, Howmedica, Rutherford, NJ) cementless acetabular components were acquired at revision surgery. All the components articulated against CoCrMo femoral heads of 32-mm diameter. The penetration depth and angle were measured using the shadowgraph technique. The wear volume was then calculated using Kabo's formula. Using weighted linear regression analysis, the mean penetration rate and mean volumetric wear rate were calculated to be 0.23 (SE, 0.03) mm3/y and 96 (SE, 13) mm3/y, respectively. The creep component was not found to be significantly different from zero. The clinical wear factor, k(clinical), for this cohort was also calculated using linear regression analysis but with the assumption that creep was zero. The value found, k(clinical) = 1.93 (SE, 0.29) x 10(-6) mm3/N-m, was similar to those in previous studies involving cemented joints with a 22-mm femoral head diameter. The similar k(clinical) values of these substantially different joint types suggest that the high volumetric wear rate for the PCA joint can be attributed entirely to its larger head size and the younger, more active, patient profile. Fixation technique and metal backing seem not to influence the rate of wear.

Acetabulum↗

PubMedDate not supplied

[Comparison of high-resolution liquid chromatography versus microparticle enzyme immunoassay for the measurement of sirolimus levels in renal transplantation].

OBJECTIVE: To compare sirolimus levels measured in whole blood using two analytical techniques: high-resolution liquid chromatography and microparticle enzyme immunoassay, and to evaluate whether hemoglobin, hematocrit, and time from kidney transplantation influence results obtained using the immune-enzymatic technique. METHOD: A retrospective, observational study in which all transplanted patients with at least one measurement of sirolimus levels using high-resolution liquid chromatography or microparticle enzyme immunoassay from October 2004 to May 2005 were consecutively included. For statistical comparisons simple linear regression, ANCOVA, intra-class correlation coefficient, and the method of agreement limits were all used. RESULTS: Ninety-one patients were assessed for a total of 307 measurements (median: 2, inter-quartile range: 1-4, range: 1-15) of sirolimus levels. The straight-line equation using the linear regression analysis was as follows: MEIA = 0.70 (95% CI: 0.39-1.01) + 1.14 (95% CI: 1.10-1.17) x HPLC/UV. The intra-class correlation coefficient between both measurements was 0.955 (95% CI 0.944-0.964). Mean overestimation using enzyme immunoassay was 24.8% +/- 19.4%. Difference in means between both measurements was 1.9 +/- 1.3 ng/mL. Agreement limits were established between -0.8 ng/mL (95% CI: -1.05; -0.55) and +4.6 ng/mL (95% CI: 4.35; 4.85). Factors such as post-transplant time, hemoglobin, and hematocrit did not influence overestimates obtained using enzyme immunoassays. These results were not influenced by non-independence in measurements. CONCLUSIONS: Despite enzyme immunoassay overestimates in establishing sirolimus levels in whole blood, its correlation with chromatography is acceptable. Added to its benefits versus chromatographic techniques, this renders enzyme immunoassay a good alternative for the measurement of sirolimus levels in whole blood.

Chromatography, High Pressure Liquid↗

PubMed2000

Risk factors for community-acquired pneumonia diagnosed upon hospital admission. British Thoracic Society Pneumonia Study Group.

A case-control study of risk factors for community-acquired pneumonia in adults admitted to hospital is reported. Cases were surviving patients (n = 178) admitted to 14 hospitals in England. Controls were individuals (n = 385) randomly selected from the electoral registers of the areas served by the hospitals. The two groups were compared with regard to risk factors for pneumonia using a standardized postal questionnaire. Independent risk factors associated with cases in log-linear regression analysis were age, heart disease (as indicated by congestive heart failure and/or digitalis treatment), lifetime smoking history, chronic airway disease (chronic bronchitis and/or asthma), occupational dust exposure, pneumonia as a child, single marital status and unemployment. Corticosteroid and bronchodilator therapy were also independent risk factors in the log-linear regression analysis, but may reflect the severity of underlying lung disease for which these drugs were prescribed. These data suggest that cigarette smoking is the major avoidable risk factor for acute pneumonia in adults.

Adolescent↗

PubMed1996

Studies on acid oils and fatty acids for chickens III. Effect of chemical composition on metabolisable energy of by-products of vegetable oil refining.

1. Fourteen by-products of oil refining, selected for their variability in free fatty acid and unsaponifiable contents, were analysed chemically with the objective of relating the determined ME values of the products to chemical composition by means of multiple linear regression analysis. Refined sunflower oil was included as a reference fat. 2. Twenty-one 2-week-old chicks were used to determine fat digestibilities and AMEn values of diets, using the total collection method. Fats were included in a wheat-soyabean meal diet at 100 g/kg. Multiple linear regression analysis was used to express the ME values of fats as functions of the parameters measured (moisture, gross energy, impurities, unsaponifiables, non eluted material, free fatty acid content, unsaturated: saturated ratio, peroxide value, TBA test). 3. The ME of the fat products lay in the range l2.62 to 24.35 MJ/kg, and 29.26 MJ/kg for refined sunflower oil. Free fatty acid content of the fats was shown to be a poor predictor of their ME values, whereas non eluted material (NEM) of the fat products showed a good correlation with their ME. A regression equation could be derived (R2 0.6548; SEE 2.0064) with the unsaturated: saturated ratio (U:S) and NEM. An ME prediction equation based on the U:S, NEM and unsaponifiable content is also proposed (R2= 0.7l68; SEE= 1.9058).

Animal Feed↗

PubMed2000

Measurement of odor intensity by an electronic nose.

The possibility of using electronic noses (ENs) to measure odor intensity was investigated in this study. Two commercially available ENs, an Aromascan A32S with conducting polymer sensors and an Alpha M.O.S. Fox 3000 with metal oxide sensors, as well as an experimental EN made of Taguchi-type tin oxide sensors, were used in the experiments. Odor intensity measurement by sensory analysis and EN sensor response were obtained for samples of odorous compounds (n-butanol, CH3COCH3, and C2H5SH) and for binary mixtures of odorous compounds (n-butanol and CH3COCH3). Linear regression analysis and artificial neural networks (ANN) were used to establish a relationship between odor intensity and EN sensor responses. The results, suggest that large differences in sensor response to samples of equivalent odor intensity exist and that sensitivity to odorous compounds varies according to the type of sensors. A linear relationship between odor intensity and averaged sensor response was found to be appropriate for the EN based on conducting polymer sensors with a correlation coefficient (r) of 0.94 between calculated and measured odor intensity. However, the linear regression approach was shown to be inadequate for both ENs, which included metal oxide-type sensors. Very strong correlation (r = 0.99) between measured odor intensity and calculated odor intensity using the ANN developed were obtained for both commercial ENs. A weaker correlation (r = 0.84) was found for the experimental instrument, suggesting an insufficient number of sensors and/or not enough diversity in sensor responses. The results demonstrated the ability of ENs to measure odor intensity associated with simple mixtures of odorous compounds and suggest that ANN are appropriate to model the relationship between odor intensity measurement and EN sensor response.

Air Pollution↗

PubMed1993

A microcomputer program to determine the precision of elimination rate constant and half-life estimates when sampling time is short.

First-order elimination of drugs is often assumed in pharmacokinetics and elimination rate constant is then frequently determined by log-linear regression analysis from plasma concentration measurements. When the time which elapses between the first and the last plasma sample is short compared to the decay half-life, the elimination rate constant may not be determined with satisfactory precision, in particular because of analytical error. Application of basic principles of linear regression analysis allowed us to quantify the theoretical effect of analytical error on the determination of the drug elimination rate constant in that situation. It was highlighted that the precision of that determination could be efficiently improved by measuring samples in replicate, which should be recommended in practice. A user-friendly program was developed which can be used prospectively to optimize sampling strategy, and retrospectively to estimate the precision of parameter estimates. The program works on IBM PC and compatible microcomputers and is available on request.

Drug Monitoring↗

PubMed2006

Automatic estimation of detector radial position for contoured SPECT acquisition using CT images on a SPECT/CT system.

An algorithm was developed to estimate noncircular orbit (NCO) single-photon emission computed tomography (SPECT) detector radius on a SPECT/CT imaging system using the CT images, for incorporation into collimator resolution modeling for iterative SPECT reconstruction. Simulated male abdominal (arms up), male head and neck (arms down) and female chest (arms down) anthropomorphic phantom, and ten patient, medium-energy SPECT/CT scans were acquired on a hybrid imaging system. The algorithm simulated inward SPECT detector radial motion and object contour detection at each projection angle, employing the calculated average CT image and a fixed Hounsfield unit (HU) threshold. Calculated radii were compared to the observed true radii, and optimal CT threshold values, corresponding to patient bed and clothing surfaces, were found to be between -970 and -950 HU. The algorithm was constrained by the 45 cm CT field-of-view (FOV), which limited the detected radii to < or = 22.5 cm and led to occasional radius underestimation in the case of object truncation by CT. Two methods incorporating the algorithm were implemented: physical model (PM) and best fit (BF). The PM method computed an offset that produced maximum overlap of calculated and true radii for the phantom scans, and applied that offset as a calculated-to-true radius transformation. For the BF method, the calculated-to-true radius transformation was based upon a linear regression between calculated and true radii. For the PM method, a fixed offset of +2.75 cm provided maximum calculated-to-true radius overlap for the phantom study, which accounted for the camera system's object contour detect sensor surface-to-detector face distance. For the BF method, a linear regression of true versus calculated radius from a reference patient scan was used as a calculated-to-true radius transform. Both methods were applied to ten patient scans. For -970 and -950 HU thresholds, the combined overall average root-mean-square (rms) error in radial position for eight patient scans without truncation were 3.37 cm (12.9%) for PM and 1.99 cm (8.6%) for BF, indicating BF is superior to PM in the absence of truncation. For two patient scans with truncation, the rms error was 3.24 cm (12.2%) for PM and 4.10 cm (18.2%) for BF. The slightly better performance of PM in the case of truncation is anomalous, due to FOV edge truncation artifacts in the CT reconstruction, and thus is suspect. The calculated NCO contour for a patient SPECT/CT scan was used with an iterative reconstruction algorithm that incorporated compensation for system resolution. The resulting image was qualitatively superior to the image obtained by reconstructing the data using the fixed radius stored by the scanner. The result was also superior to the image reconstructed using the iterative algorithm provided with the system, which does not incorporate resolution modeling. These results suggest that, under conditions of no or only mild lateral truncation of the CT scan, the algorithm is capable of providing radius estimates suitable for iterative SPECT reconstruction collimator geometric resolution modeling.

Algorithms↗

PubMed1999

Altered central nervous system processing of baroreceptor input following hindlimb unloading in rats.

The effect of cardiovascular deconditioning on central nervous system processing of baroreceptor afferent activity was evaluated following 14 days of hindlimb unloading (HU). Inactin-anesthetized rats were instrumented with catheters, renal sympathetic nerve electrodes, and aortic depressor nerve electrodes for measurement of mean arterial pressure, heart rate, renal sympathetic nerve activity (RSNA), and aortic depressor nerve activity (ADNA). Baroreceptor and baroreflex functions were assessed during infusion of phenylephrine and sodium nitroprusside. Central processing of baroreceptor afferent input was evaluated by linear regression relating RSNA to ADNA. The maximum baroreflex-elicited increase in RSNA was significantly reduced in HU rats (122 +/- 3.8 vs. 144 +/- 4.9% of baseline RSNA), whereas ADNA was not altered. The slope (-0.18 +/- 0.04 vs. -0.40 +/- 0.04) and y-intercept (121 +/- 3.2 vs. 146 +/- 4.3) of the linear regression relating increases in efferent RSNA to decreases in afferent ADNA during hypotension were significantly reduced in HU rats. There were no differences during increases in arterial pressure. Results demonstrate that the attenuation in baroreflex-mediated increases in RSNA following HU is due to changes in central processing of baroreceptor afferent information rather than aortic baroreceptor function.

Animals↗

PubMed2005

Prostate cancer volume -- can it be predicted preoperatively?

INTRODUCTION: The prostate cancer volume (PCvol) is described as a significant predictor for tumor progression after radical prostatectomy, but its determination has not become a routine procedure yet due to high demands on technical standards, labor intensity, and costs. The objective of this study is to predict the PCvol by using common preoperative variables. MATERIAL AND METHODS: Between 1996 and 2001, 365 whole-mounted prostatectomy specimens, processed according to the Stanford protocol, were used for computerized reconstruction of the total PCvol. Widely accepted preoperative variables such as prostate-specific antigen (PSA), digital rectal examination findings, and Gleason score and grading (WHO) of the biopsy cores were correlated and analyzed for a relation to the PCvol by Spearman rho method and Mann-Whitney U test. Integrating these parameters in a multiple linear regression model, independent variables predicting the PCvol were determined, multiplied by their risk factors, and used for calculation of the estimated PCvol. In order to evaluate the precision of our results, we correlated measured and estimated tumor volumes. A nomogram was constructed, in order to visualize our results. RESULTS: Multiple linear regression analysis revealed categorized PSA, grading (WHO), and Gleason score to be independent predictors for the PCvol. The estimated PCvol ranged from 0.5 to 9.8 cm(3) and the measured PCvol from 0.02 to 53 cm(3). An identical mean value of 4.1 cm(3) was observed. The Spearman rho method showed a highly significant correlation (coefficient = 0.5) between estimated and measured PCvol (p < 0.001). CONCLUSIONS: The PCvol is regarded as a significant predictive parameter of tumor progression after radical prostatectomy, but due to its time-consuming determination, it has not become a routine procedure yet. Currently used preoperative parameters such as PSA and grading (WHO) and Gleason score of the biopsy cores do predict the total tumor volume. These results were reconfirmed by correlation analysis. Consequently, by use of our nomogram, the labor-intensive measurement of the PCvol becomes unnecessary.

Adult↗

PubMed2006

Higher urine 1-hydroxy pyrene glucuronide (1-OHPG) is associated with tobacco smoke exposure and drinking maté in healthy subjects from Rio Grande do Sul, Brazil.

BACKGROUND: The highest rates of esophageal squamous cell carcinoma (ESCC) in Brazil occur in Rio Grande do Sul, the most southern state, which has incidence rates of 20.4/100,000/year for men and 6.5/100,000/year for women. Exposure to carcinogenic polycyclic aromatic hydrocarbons (PAHs) through tobacco smoke and other sources may increase the risk of ESCC. The aims of the current study were to investigate the degree and sources of PAH exposure of the inhabitants of this region of southern Brazil. METHODS: Two hundred healthy adults (half smokers, half non smokers, half male and half female) were recruited, given a standardized questionnaire, and asked to provide a urine sample for measurement of 1-hydroxypyrene glucuronide (1-OHPG), a PAH metabolite). Urine 1-OHPG concentrations were measured using immunoaffinity chromatography and synchronous fluorescence spectroscopy and urine cotinine was measured using a dipstick test. We examined factors associated with 1-OHPG concentration using Wilcoxon tests and multiple linear regression. RESULTS: Urine 1-hydroxypyrene glucuronide (1-OHPG) was successfully measured on 199 subjects. The median (interquartile range) of urine 1-OHPG in the 199 participants was 2.09 pmol/mL (0.51, 5.84). Tobacco smoke exposure and maté drinking were statistically significantly associated with higher urine 1-OHPG concentrations in the multivariate linear regression model. CONCLUSION: Tobacco smoke and maté both contribute to high levels of benzo[a]pyrene exposure in the people of southern Brazil. This high PAH exposure may contribute to the high rates of ESCC observed in this population. The increased urine 1-OHPG concentrations associated with maté suggest that contaminants, not just thermal injury, may help explain the increased risk of ESCC previously reported for maté consumption.

Alcohol Drinking↗

PubMed2006

Theory of mind and executive function: working-memory capacity and inhibitory control as predictors of false-belief task performance.

This study of the relationship between theory of mind and executive function examined whether on the false-belief task age differences between 3 and 5 ears of age are related to development of working-memory capacity and inhibitory processes. 72 children completed tasks measuring false belief, working memory, and inhibition. Significant age effects were observed for false-belief and working-memory performance, as well as for the false-alarm and perseveration measures of inhibition. A simultaneous multiple linear regression specified the contribution of age, inhibition, and working memory to the prediction of false-belief performance. This model was significant, explaining a total of 36% of the variance. To examine the independent contributions of the working-memory and inhibition variables, after controlling for age, two hierarchical multiple linear regressions were conducted. These multiple regression analyses indicate that working memory and inhibition make small, overlapping contributions to false-belief performance after accounting for age, but that working memory, as measured in this study, is a somewhat better predictor of false-belief understanding than is inhibition.

Adult↗