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PubMedDate not supplied

Prediction of mandibular growth in Japanese children age 4 to 9 years.

PURPOSE: The purpose of this study was to propose mathematical models for predicting mandibular growth direction and amount in children with normal skeletal relationship from 4 to 9 years of age using the craniofacial characteristics found on the head films. METHODS: Lateral cephalograms of 27 Japanese children with normal occlusion at 4 (T1) and 9 (T2) years of age were traced and measured. Fifteen linear and angular measurements were performed. The angle NSGn and the distance S-Gn were used to represent the growth direction of the mandible and its growth amount, respectively. The data were analyzed by multiple linear regression analysis. RESULTS: The multiple regression analysis revealed 2 models for the mandibular growth prediction. The equation (model) for the mandibular growth direction is YD=-39.844+1.206 X1 +0.333 X2, where YD is the predicted value of the angle NSGn at T2. X1 is the value of the angle NSGn at T1 and X2 is the value of the angle SNB at T1 (R2=0.719, P<0.05). The equation for the mandibular growth amount is YA=99.052+0.782 X3-0.517 X4, where YA is the predicted value of the distance S-Gn at T2. X3 is the distance S-Gn at T1 andX4is the angle NSAr at T1 (R2=0.610, P< 0.05). CONCLUSIONS: The direction of the mandibular growth at 9 years of age can be predicted by 72% with the regression equation using the angles NSGn and SNB at 4 years of age. The amount of growth of the mandible can be predicted by 62% by using the distance S-Gn and the angle NSAr at 4 years old. The model for the growth amount provides a relatively lower predictive value than that of the growth direction.

Cephalometry↗

PubMed2007

Facets of acculturation and their diverse relations to body shape concern in Fiji.

OBJECTIVE: The present study examines the relation between acculturation and body shape concern in Fiji--a society undergoing rapid social change. METHOD: Data were from two cohorts of ethnic Fijian girls and women collected in 1998 (n = 115). A factor analysis was performed to identify dimensions of acculturation. The association of these with body shape concern was examined with linear regression. RESULTS: Three dimensions of acculturation were identified. Multiple linear regression models demonstrated that each of these dimensions of acculturation had a unique relation to body shape concern. The adjusted R(2) for the fully adjusted model relating acculturation to body concern was 0.63, indicating a substantial degree of shared variation between measures of body shape concern and measures of acculturation. CONCLUSION: Acculturation may have a strong impact on body shape concern in Fiji. However, acculturation is a multidimensional construct and does not likely have a monolithic relation to body shape concern.

Acculturation↗

PubMed1997

The internal dose of passive smoking at home depends on the size of the dwelling.

As part of a longitudinal study two urine samples (survey 1 in 1991 and survey 2 in 1992) were collected from 602 elementary school children to investigate the relationship between urinary cotinine excretion (UCE) and the daily consumption of cigarettes at home (exposure). Size of the dwelling, educational level, and maternal smoking were taken into consideration as additional predictors. The history regarding parental smoking habits and confounding variables was ascertained by standardized questionnaires completed by the parents. Cotinine was measured using gas chromatography selected ion monitoring. UCE was expressed as cotinine/creatinine (ng/mg). In children with detectable UCE in survey 1 (35%) and in survey 2 (44%) the excretion ranged between 1.5 and 24.7 ng/mg (5-95%) and between 1.2 and 25.2 ng/mg, respectively. UCE measurements in both surveys were highly correlated (r = 0.65, P = 0.0001), and 59.6% of the UCE in survey 2 can be explained in linear regression by the UCE in survey 1. Using multiple linear regression, the categorized number of cigarettes reported to be consumed at home (20 cigarettes and more: 1991, P = 0.0001; 1992, P = 0.0003) and low educational level of the parents (P = 0.011 in 1991, P = 0.04 in 1992) were positively associated with UCE, whereas the size of the dwelling turned out to be negatively associated with UCE (P = 0.12 in 1991, P = 0.001 in 1992). In small dwellings (< or = 80 m2) the effect of exposure on UCE was much more pronounced. In conclusion, a single UCE measurement provides information which is widely stable within a yearly interval and is related to passive smoke history as well as to socio-economic status and the size of the dwelling. The latter variable should be considered as an effect modifier of exposure on internal dose and should be taken into account in future studies on passive smoke exposure.

Analysis of Variance↗

PubMed2001

Attenuation of paraquat-induced dopaminergic toxicity on the substantia nigra by (-)-deprenyl in vivo.

(-)-Deprenyl (DEP) had been shown to slow of progression of Parkinson's disease (PD). The present study sought to determine whether DEP would attenuate the nigrostriatal system damage induced by intranigral administration of the herbicide paraquat (PQ) as a model of parkinsonism in vivo. Neurochemical and behavioral observations of Wistar rats were the focus of our study. In the neurochemical observation, the PQ injected in the rats caused dose-dependent depletion of dopamine (DA) in the ipsilateral striata. The coadministration of DEP with PQ partially increased the striatal DA level. The prediction of the striatal DA levels was calculated by regression coefficients obtained from multiple linear regression (r(2) = 0.82): DA level (% of control) = 103.34 - 9.58 PQ (nmol) + 0.79 DEP (nmol). It was demonstrated that the high dose of 20 nmol DEP could significant attenuate the PQ (5 nmol)-elicited dopaminergic toxicity (p < 0.05). In the behavioral observation, the intranigral injection of PQ into the rats caused a rotation behavior contralateral to the lesioned side in response to apomorphine administration (0.5 mg/kg, sc). This apomorphine-induced rotational behavior could also be attenuated significantly by coadministration of DEP (20 nmol) and PQ (5 nmol) compared with PQ-treated (5 nmol) animals (p < 0.05). The above observations indicate that DEP could provide a protective effect on the moderate injury elicited by PQ toxicity of the nigrostriatal dopaminergic system. DEP might be a useful therapeutic agent in treating patients with early-stage PD.

Animals↗

PubMed2006

Evaluation of regression models in metabolic physiology: predicting fluxes from isotopic data without knowledge of the pathway.

This study explores the ability of regression models, with no knowledge of the underlying physiology, to estimate physiological parameters relevant for metabolism and endocrinology. Four regression models were compared: multiple linear regression (MLR), principal component regression (PCR), partial least-squares regression (PLS) and regression using artificial neural networks (ANN). The pathway of mammalian gluconeogenesis was analyzed using [U-(13)C]glucose as tracer. A set of data was simulated by randomly selecting physiologically appropriate metabolic fluxes for the 9 steps of this pathway as independent variables. The isotope labeling patterns of key intermediates in the pathway were then calculated for each set of fluxes, yielding 29 dependent variables. Two thousand sets were created, allowing independent training and test data. Regression models were asked to predict the nine fluxes, given only the 29 isotopomers. For large training sets (>50) the artificial neural network model was superior, capturing 95% of the variability in the gluconeogenic flux, whereas the three linear models captured only 75%. This reflects the ability of neural networks to capture the inherent non-linearities of the metabolic system. The effect of error in the variables and the addition of random variables to the data set was considered. Model sensitivities were used to find the isotopomers that most influenced the predicted flux values. These studies provide the first test of multivariate regression models for the analysis of isotopomer flux data. They provide insight for metabolomics and the future of isotopic tracers in metabolic research where the underlying physiology is complex or unknown.

Journal Article↗

PubMed1990

A comparison of multivariable mathematical methods for predicting survival--III. Accuracy of predictions in generating and challenge sets.

This paper concludes a study of "performance variability" when four methods of multivariable analysis--multiple linear regression, discriminant function analysis, multiple logistic regression, and two arrangements of Cox's proportional hazards regression--were applied to the same stratified random samples of "generating sets" containing seven different statistical distributions of cogent biologic attributes in a composite staging system for a large cohort of patients with lung cancer. Each model developed from the generating sets was also applied for predictions in a previously sequestered "challenge set". Across the different generating sets, the multivariable methods showed good agreement with one another in the stepwise choice of first two powerful predictor variables, but not in the sequence of subsequent choices or in the standardized coefficients assigned to the same collection of "forced" variables. In concordance of predictions for individual patients in the generating sets, the overall proportions of disagreement for pairs of methods ranged from 0 to 28%, and kappa values ranged from 0.49 to 1.00. The accuracy of individual predictions showed relatively similar results when the different methods were applied to the same generating set. Across the generating sets, the different methods showed similar total results but substantial variations in predictions for alive and dead patients. When the models from the generating sets were applied for predictions in the challenge set, the results showed an analogous pattern: similar accuracy within models for overall and live/dead predictions, but substantial variations in live/dead predictions across models derived from different generating sources. The results showed that the multivariable methods often had good agreement with one another in predictions for groups but not for individual persons; and that no single method was superior to the others or to the composite staging system. We conclude that multivariable analytic methods may be most effective and consistent if used to find the few most powerful predictor variables, omitting the many other variables that may be "statistically significant" but less cogent. The powerful predictors may sometimes be best constructed, before the analysis begins, as composite variables containing appropriate unions or ordinal arrangements of elemental candidate variables.

Cohort Studies↗

PubMed2003

Influence of solvation interactions on the zeta potential of titania powders.

The influence of solvation interactions on the surface charge of titania powders was studied by means of linear solvation energy relationships (LSER). The zeta potential (ZP) of titania powders and the effect of water content were determined in a series of alcohols, including methanol, ethanol, 1-propanol, isopropanol, and 1-butanol. The ZPs against the solvents' 13 LSER descriptors were analyzed by principal component analysis (PCA), cluster analysis, multiple linear regression (MLR), and stepwise multiple regression (SMR). Very good correlation between ZP and LSER parameter was obtained. One LSER parameter, relative dielectric constant, epsilon, was used to establish the LSER equation. The ZP of titania powders in pure alcohols can be reasonably calculated by an empirical formula: ZP=13.43-213.63.1/epsilon. The results show that epsilon is the most important factor governing the ZP of titania powders. The results also suggest that the effect of solvation interactions on ZP is a result of the electrostatic interactions between powders and solvents.

Alcohols↗

PubMedDate not supplied

Field cost of activity in the kit fox, Vulpes macrotis.

Field metabolic rates and daily movement distances were measured in 26 individual kit foxes (Vulpes macrotis) over a 29-mo period in the southern Mojave Desert of California. Kit foxes traveled long distances (up to 32 km d(-1)), with males usually traveling farther than females. Daily movement distances were affected by season, since males traveled the greatest distances in spring and females traveled farthest in summer. Individual foxes tracked multiple times demonstrated repeatability of daily movement distance between nights, between summer and winter, and between consecutive winters. The field cost of activity per unit distance was estimated as 15.6 kJ km(-1) from the partial regression coefficient of a multiple linear regression model, a value not significantly different from the incremental cost of locomotion derived from laboratory measurements. The field cost of activity was not affected by season, despite the expectation of higher costs of activity in the winter with increased thermoregulatory expenditure. The large daily movement distances resulted in significant activity energy expenditure (11%-33% of field metabolic rate), with a mean of 21% of field metabolic rate expended in activity during nonreproductive seasons.

Adaptation, Physiological↗

PubMed2004

Fruit and vegetable consumption and bone mineral density: the Northern Ireland Young Hearts Project.

BACKGROUND: Studies examining the relation between bone mineral density (BMD) and fruit and vegetable consumption during adolescence are rare. OBJECTIVE: Our objective was to determine whether usual fruit and vegetable intakes reported by adolescents have any influence on BMD. DESIGN: BMD was measured by dual-energy X-ray absorptiometry at the nondominant forearm and dominant heel in a random sample of 12-y-old boys (n = 324), 12-y-old girls (n = 378), 15-y-old boys (n = 274), and 15-y-old girls (n = 369). Usual fruit and vegetable consumption was assessed by an interviewer-administered diet history method. Relations between BMD and fruit and vegetable intake were assessed by using regression modeling. RESULTS: Using multiple linear regression to adjust for the potential confounding influence of physical and lifestyle factors, we observed that 12-y-old girls consuming high amounts of fruit had significantly higher heel BMD (beta = 0.037; 95% CI: 0.017, 0.056) than did the moderate fruit consumers. No other associations were observed. CONCLUSION: High intakes of fruit may be important for bone health in girls. It is possible that fruit's alkaline-forming properties mediate the body's acid-base balance. However, intervention studies are required to confirm the findings of this observational study.

Absorptiometry, Photon↗

PubMedDate not supplied

[Secular trends in the stature of Brazilian Navy recruits born from 1940 and 1965].

The present paper reports data on secular trends in the stature of Brazilian Navy recruits born from 1940 to 1965. The final sample included 3269 individuals aged 18.00-18.99. Statistics performed were: ANOVA (one-way and two-way), Sheffe test, simple linear regression between stature and year of birth, and multiple linear regression adjusting for level of schooling (beta coefficient) and chi-square. Results indicated a progressive growth trend in stature of 0.1 cm/yr. for the country as a whole. The trend was also observed for nearly all regions and two out of three levels of schooling and can be explained by improvement in some of the country's health indicators. One important characteristic was a higher level of schooling observed among Navy recruits, suggesting that these individuals represent a highly select group, and that therefore data on the Navy cannot be applied directly to the Brazilian population as a whole.

Adolescent↗

PubMed1990

The relationship between neck circumference, radiographic pharyngeal anatomy, and the obstructive sleep apnoea syndrome.

We have studied the predictive importance of neck circumference, obesity, and several radiographic pharyngeal dimensions for obstructive sleep apnoea (OSA), in 66 patients. OSA was quantified as the mean hourly number of greater than 4% dips in arterial oxygen saturation during sleep. Neck circumference (correlation coefficient (r) = 0.63, 95% confidence interval (C.I.) 0.46-0.76), obesity index (r = 0.54, 95% C.I. 0.39-0.69), hyoid position (r = 0.40, 95% C.I. 0.17-0.59), soft palate length (r = 0.31, 95% C.I. 0.08-0.51), and hard palate-to-spine angle (r = 0.29, 95% C.I. 0.04-0.49), correlated significantly with saturation dips in single regression analysis. In stepwise multiple linear regression analysis (saturation dip rate as the dependent variable), only neck size and retroglossal space were significant independent correlates (total r2 = 0.42, 95% C.I. 0.22-0.61, p less than 0.0001). We conclude that the relationships between general obesity, hyoid position, soft palate length, and OSA are probably secondary to variation in neck circumference.

Female↗

PubMedDate not supplied

Facial dimensions and predictors of fit for half-mask respirators in Koreans.

This study investigated the relationship between facial dimensions and the fit of half-mask respirators using fit factors and selected good facial dimension predictor(s) of fit for designing respirators for Korean workers. Three different brands of half-mask respirators-YS, SG, and 3M-were fit-tested on 112 men and 38 women using TSI Portacount 8020, and fit factors were determined. Before fit-testing, 10 facial dimensions were measured. Data were analyzed by descriptive statistics, Pearson's correlation analysis, and quadratic polynomial regression analysis with log-transformed fit factors (LNFF). However, some of the relationships between LNFF and facial dimensions in brand/gender subgroups were found to be curvilinear rather than linear. Because this result indicated that a multiple polynomial regression model including quadratic terms might be more appropriate than a multiple linear regression, data were also analyzed with a quadratic term by examination of the coefficient of partial correlation. No common facial dimension variables were found to be significant for all nine brand/gender subgroups, but the coefficient of regression for the linear term of the bitragion-menton arc was significant in five of nine brand/gender subgroups including male subjects of all three respirator brands. The 3M mask had the highest coefficient of determination values compared with other brands. Using the quadratic term for the 3M mask, face width (bizygomatic breadth) and nose protrusion were good predictors of half-mask fit. In four of nine brand/gender subgroups, nose protrusion was a good predictor of fit through analysis using a quadratic term. Results indicate that face width, bitragion-menton arc, and nose protrusion should be preferentially considered when designing a half-mask respirator for Korean workers.

Adult↗

PubMed2006

Association between intention to stay on the job and job satisfaction among Japanese nurses in small and medium-sized private hospitals.

In order to examine the relationship between the intention to stay on the job and job satisfaction among Japanese nurses, and to obtain clues for preventing turnover, we conducted a questionnaire survey. The subjects involved in the survey included 625 female nurses (registered nurses, licensed practical nurses and assistant nurses) working in 4 small and medium-sized private hospitals, excluding directors of nursing. Of the 625 questionnaires distributed, 556 (89.0%) were returned. After excluding the questionnaires with missing values, 480 questionnaires were analyzed (effective response rate, 76.8%). The average age of the respondents was 32.8 yr (range: 20-65). The content of the questionnaire was nurse attributes, job satisfaction (30 items) and intention to stay on the job. For job satisfaction, factor analysis (principal factor method and promax rotation) was performed, and factors with an eigenvalue of > or =1 were extracted. Six factors were extracted by factor analysis. These factors were interpreted as "Work as specialists" (1st factor), "Relationship with superiors" (2nd factor), "Comfortable life" (3rd factor), "Relationship among nurses" (4th factor), "Communication with physicians" (5th factor) and "Working conditions" (6th factor). The factor scores were calculated and used as a scale for the evaluation of job satisfaction. To investigate the factors associated with intention to stay on the job among nurses, the standard partial regression coefficient was computed by multiple linear regression analysis, with intention to stay on the job as the dependent variable, and nurse attributes and job satisfaction (factor scores) as independent variables. Various factors including the organizational culture of each hospital may affect the relationship between job satisfaction and the intention to stay on the job. In order to adjust for these factors, differences among hospitals were included in the statistical model as independent variables. The result of the multiple regression analysis suggests that the intention to stay on the job was higher among nurses who were older and more satisfied with work as specialists (1st factor) and working conditions (6th factor).

Adult↗

PubMed1997

Predictive value of Doppler umbilical artery velocimetry in a low risk population with normal fetal biometry. A prospective study of 2016 women.

OBJECTIVE: To assess the predictive value of Doppler umbilical artery velocimetry in a low-risk population with normal fetal biometry. STUDY DESIGN: Multicenter prospective study in 17 hospitals with prenatal clinics in France. Two thousand sixteen women who, before 28 weeks gestation were defined as at low risk after routine consultation and after ultrasound. Doppler umbilical artery velocimetry was performed between 28 and 34 weeks gestation. Confounding factors were used to perform multivariate regression. RESULTS: 1903 cases were analysed and 192 (10.1%) had an abnormal Doppler Resistance Index (RI). The abnormal Doppler group contained a significantly higher frequency of severe and moderate small for gestational age infants (SGA), both severe and moderate with a sensitivity of 25.5 and 18.8% respectively. There was no difference in hypertensive disorders or criteria of fetal distress. Mean birth weight was very significantly lower in the abnormal group (162 g). Birth weight was very significantly linked to RI after taking into account confounding variables in the multiple linear regression model (continuous relationship). After multiple logistic regression, the odds ratio associated with an abnormal Doppler result, adjusted for all the confounding factors, was 2.3 (95% CI 1.5-3.7) for moderate SGA and 3.5 (95% CI of 1.8-7.1) for severe SGA. CONCLUSION: Low umbilical Doppler RI is predictive with moderate or severe SGA in a low-risk population with normal fetal biometry, even when the information generally available in clinical practice and ultrasound parameters are taken into account. There is a continuous relationship between RI and birthweight. This predictive value cannot, however, lead to an improvement in neonatal health unless effective measures to prevent SGA exist and umbilical Doppler should not be used in low-risk population on a routine basis.

Birth Weight↗

PubMed1997

Influence of regional cardiovascular mortality on the use of angiography after acute myocardial infarction.

Utilization of angiography after acute myocardial infarction (AMI) treated with thrombolytics has been shown in large clinical trials to be related primarily to the availability of the procedure and not individual clinical circumstances. This study evaluated the regional influence of overall population cardiovascular mortality on utilization of angiography in the United States participants of the Global Utilization of Streptokinase and t-PA for Occluded Arteries (GUSTO-1) trial. Published summary statistics from GUSTO-1 and U.S. Census Bureau 1991 data were evaluated using simple and multiple linear regression with analysis for outliers. Region predictor variables (age adjusted) included mean total cardiovascular deaths/100,000/year (ICD/9 codes 390 to 459), mean coronary artery disease deaths/ 100,000/year (ICD/9 codes 410 to 414), and mean stroke deaths/100,000/year (ICD/9 codes 430 to 438), with the major outcome being regional proportion of GUSTO-1 patients undergoing angiography during the hospital stay after treatment with thrombolysis. All 3 cardiovascular death rates varied significantly by region (p < 0.00002) with no significant difference in GUSTO-1 mortality by region (p = 0.25). Simple linear regression analysis revealed associations between regional death rates and angiography use (r = 0.60, p = 0.12; r = 0.39, p = 0.33; r = 0.81, and p = 0.015). Multiple stepwise linear regression analysis found regional death rate due to stroke as the strongest predictor of angiography use with 65.86% of the variation explained by the model. New England was found to be a consistent outlier with reduced angiography use because of its background regional disease burden. This study confirms regional bias in the use of angiography in GUSTO-1. This form of operator bias appears to be due to more aggressive practice patterns in regions, except New England, where the overall cardiovascular disease burden is greater in terms of lives lost per 100,000 per year.

Age Factors↗

PubMed2006

Cognitive performance of patients with mesial temporal lobe epilepsy is not associated with human prion protein gene variant allele at codons 129 and 171.

Cognitive impairment has long been recognized in people with medically refractory epilepsies. Mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS), the most common surgically remediable epileptic syndrome, has been associated with a cellular prion protein (PrPc) gene (Prnp) variant allele at codon 171. The polymorphism consisting of a methionine-for-valine substitution at codon 129 has been associated with early cognitive deterioration in elderly people and patients with Down syndrome. The same variant allele in homozygosis (V129V) has been associated to a lower long-term memory in healthy humans. PrPc mediates several processes related to neuroplasticity, and its role in cognitive processes remains unknown. In this study, we evaluated the genetic contribution of Prnp alleles to cognitive performance in patients with MTLE-HS. Cognitive performance, measured with 19 neuropsychological tests, of patients with refractory MTLE-HS with the normal Prnp genotypes was compared with that of patients with the variant alleles at codons 129 and 171. With the effects of clinical, demographic, electrophysiological, and neuroimaging variable interactions controlled by multiple linear regression analysis and adjustment for multiple test comparisons, the presence of Prnp variant alleles was found not to be significantly associated to cognitive performance of patients with MTLE-HS. The presence of variant alleles at codons 129 and 171 is not associated to cognitive performance of patients with refractory MTLE-HS.

Adult↗

PubMed2000

TNF-alpha, leptin, and lymphocyte function in human aging.

Aging is associated with increased inflammatory activity and concomitant decreased T cell mediated immune responses. Leptin may provide a link between inflammation and T cell function in aging. The aim of the study was to investigate if plasma levels of tumor necrosis factor (TNF)-alpha were associated with leptin, circulating interleukin-2 receptors (sIL-2R), and phytohaemagglutinin (PHA) induced IL-2 production in whole blood in elderly humans. Circulating levels of TNF-alpha and sIL-2R were higher in elderly humans (N=42) compared to a young control group (N=37) whereas there was no difference with regard to IL-2 production. Furthermore, there were no age-related differences in serum levels of leptin. However, women had higher levels than men. In the elderly people, serum levels of leptin were correlated with TNF-alpha in univariate regression analysis and in a multiple linear regression analysis adjusting for the effect of gender and body mass index. Furthermore, TNF-alpha, but not leptin, was positively correlated to sIL-2R and negatively correlated to IL-2 production. In conclusion, increased plasma levels of TNF-alpha in aging is associated with poor IL-2 production ex vivo and lymphocyte activation in vivo. These associations do not seem to involve leptin.

Adolescent↗

PubMed1998

Histological and clinical findings in 896 consecutive prostates treated only with radical retropubic prostatectomy: epidemiologic significance of annual changes.

PURPOSE: Recognizing that the unprecedented increase in new cases of prostate cancer between 1988 and 1996 actually peaked in 1992 and has now returned to baseline, we examined our clinical and histological database for annual trends in 896 consecutive men treated only with radical prostatectomy for clinical stages T1c to T2c from 1988 to 1996. MATERIALS AND METHODS: All radical prostatectomy specimens were examined prospectively in 3 mm. step sections by 1 pathologist. Using multiple logistic regression for dichotomous variables and multiple linear regression for continuous variables, both corrected for age, we assessed the annual trends for significant changes in T1c versus T2 clinical stages, preoperative serum prostate specific antigen (PSA), cancer volume, percent Gleason grade 4/5 in the cancer, location of the cancer in the transition or peripheral zone, organ confined status, seminal vesicle invasion, positive surgical margins, prostate weight and presence of clinically insignificant cancers (less than 0.5 cc in volume). RESULTS: There were no significant annual changes in the proportion of percent Gleason grade 4/5 cancer, serum PSA, prostate weight or clinically insignificant cancers less than 0.5 cc, and the annual changes for cancer volume were only of moderate significance. T1c cancers increased from 10% in 1988 to 73% in 1996 (p=0.0001), organ confined cancers from 40 to 75% (p=0.0001) and transition zone cancers from 10 to 21% (p=0.003). Seminal vesicle invasion decreased from 18 to 5% (p=0.001) and positive surgical margins from 30 to 14 (p=0.006). Mean patient age changed from 65 to 62 years (p=0.0001). CONCLUSIONS: We believe that the extraordinary rise and fall in prostate cancer detection rates from 1990 to 1994 primarily removed previously undetected T2 cancers from the pool at large, leaving impalpable T1c cancers as the primary reservoir of prostate cancers in the United States. Importantly, cancer volume, percent Gleason grade 4/5 cancer, serum PSA and cancers less than 0.5 cc have not had a highly significant change during these critical 9 years. These data argue strongly that current PSA testing has not resulted in the detection of clinically insignificant cancers, and that PSA screening should be expanded and not restricted.

Age Distribution↗