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PubMed1991

Predictors and prevalence of obstructive sleep apnoea and snoring in 1001 middle aged men.

One thousand and one men, aged 35-65 years, were identified from the age-sex register of one group general practice. Over four years 900 men were visited at home and asked questions about symptoms potentially related to sleep apnoea and snoring. Height, weight, neck circumference, resting arterial oxygen saturation (SaO2), and spirometric values were also determined. All night oximetry was then performed at home and the tracing analysed for the number of dips in SaO2 of more than 4%. Subjects with more than five dips of 4% SaO2 or more per hour were invited for sleep laboratory polysomnography. Seventeen per cent of the men admitted to snoring "often." Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.2%), cigarette consumption (r2 = 3.4%), and nasal stuffiness (r2 = 2%) as the only significant independent predictors of snoring. Together these account for at least a sixfold variation in the likelihood of being an "often" snorer. Forty six subjects (5%) had greater than 4% SaO2 dip rates of over five an hour and 31 of these had full sleep studies. Three subjects had clinically obvious and severe symptomatic obstructive sleep apnoea, giving a prevalence of three per 1001 men (0.3%; 95% confidence interval 0.07-0.9%). Eighteen men had obstructive sleep apnoea only when supine and in 10 the cause of the SaO2 dipping on the original home tracing was not elucidated. The greater than 4% SaO2 dip rates correlated with the history of snoring. Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.9%), alcohol consumption (r2 = 3.7%), age (r2 = 1%) and obesity (r2 = 1%) as the only significant independent predictors of the rate of overnight hypoxic dipping. This study shows that snoring in this randomly selected population correlates best with neck size, smoking, and nasal stuffiness. Obstructive sleep apnoea, defined by nocturnal hypoxaemia, correlates best with neck size and alcohol, and less so with age and general obesity.

Adult↗

PubMed1996

Interleukin-2 receptor levels in sera of patients with rheumatoid arthritis treated with sulfasalazine, parenteral gold, or placebo.

OBJECTIVE: To evaluate the associations of soluble serum interleukin-2 receptor (sIL-2R) levels in patients with rheumatoid arthritis (RA) with clinical and laboratory measures of disease activity and the predicted response to therapy. METHODS: sIL-2R levels were determined by ELISA in 137 patients with RA, not previously treated with 2nd line therapy. Patients were enrolled in a prospective, randomized, placebo controlled trial of sulfasalazine (SSZ) versus gold sodium thiomalate (GSTM), sponsored by the Cooperative Systematic Studies of Rheumatic Diseases. Using correlation analysis and regression modeling, the clinical utility of sIL-2R as a measure of disease activity and predictor of outcome was assessed. RESULTS: 91 women and 46 men with a mean age of 51 +/- 13 years and mean duration of disease of 64 +/- 78 months participated in this study. The mean sIL-2R level in all patients with RA was markedly elevated (980 +/- 589 U/ml) compared with that in healthy control subjects (446 +/- 196 U/ml; p = < 0.0001). There was no correlation between the sIL-2R levels and the joint pain/tenderness count, either at study entry or completion. There were significant positive correlations between the baseline sIL-2R and baseline erythrocyte sedimentation rate (ESR) and between the change in sIL-2R and the change in ESR. Both a multiple linear regression model and a multiple logistic regression model showed that baseline sIL-2R levels were not predictive of clinical outcome. CONCLUSION: sIL-2R levels are significantly elevated in patients with active RA and correlate positively with ESR. However, these results indicate that in patients with early RA, sIL-2R levels are neither associated with standard disease activity criteria nor predictive of the response to therapy with SSZ or GSTM, even after controlling for the simultaneous effects of other important clinical variables.

Adult↗

PubMed1995

Use of anthropometric measurements in assessing risk for coronary heart disease: a useful tool in worksite health screening?

The study examined the association between the anthropometric measurements body mass index (BMI), waist/hip ratio (WHR), and waist/thigh ratio (WTR) and cardiovascular risk factors, and assessed whether a combination of BMI and WHR could be used in routine screening of risk for cardiovascular arteriosclerotic disease at worksites. The data were obtained from a cross-sectional survey designed to assess the nutritional situation, with special reference to cardiovascular risk factors. The study population comprised 372 healthy men working on platforms in the North Sea. Serum cholesterol, triglyceride, fibrinogen, and blood pressure were positively related to the anthropometric variables, while high-density lipoprotein (HDL) was inversely related with them. The relations remained after adjusting for possible confounders, such as age, smoking, physical activity, and an indicator of dietary fat intake. In stepwise multiple linear regression models, BMI, WHR, and WTR were positively related to serum cholesterol, triglycerides, fibrinogen, diastolic blood pressure, and systolic blood pressure, and inversely related to HDL. When controlling for the anthropometric variables WHR and WTR, BMI was not independently related to fibrinogen and risk score. WHR and WTR were not independently related to systolic and diastolic blood pressure, and WTR was in addition not related to triglycerides when controlling for BMI. Overall, the anthropometric variables BMI and WHR were considered the best predictors for CAD risk when taking several risk factors into consideration. A joint variable between BMI and WHR, called "body score", constituted the four categories lean, lean android, overweight gynoid, and overweight ovoid. This body score was positively associated with levels of serum lipids, fibrinogen, and blood pressure, and inversely associated with HDL. In stepwise multiple linear regression models, controlling for possible confounding variables, body score was positively related to CAD risk. Dividing the risk score into tertiles, about 51% of the lean were in the first, while 46% of the overweight ovoid were in the third tertile. Those classified as lean android or overweight gynoid had about the same distribution, namely between 31% and 39% in each tertile if the two categories were combined. These data support the hypothesis that BMI, WHR, and WTR are independent predictors for risk factors for CAD among oil workers, and that combinations of BMI and WHR are strong enough predictors to be useful in routine screening for CAD risk at worksites. Based on these findings, supported by data from the literature, a matrix aimed at screening for follow-up at worksites is proposed.

Adult↗

PubMed1997

Serum leptin is increased in growth hormone-deficient adults: relationship to body composition and effects of placebo-controlled growth hormone therapy for 1 year.

The gene product from the ob gene, leptin, has recently been characterized in humans. The circulating level of leptin is related to body mass index (BMI) and more closely to estimates of total body fat, whereas visceral fat has been reported to be of minor importance. However, it is unknown if leptin is directly regulated by hormones that influence substrate metabolism and body composition. We studied leptin in adult growth hormone (GH)-deficient (GHD) patients substituted with GH treatment for 12 months in a parallel double-blind, placebo-controlled study. Twenty-seven GHD adults aged 44.9 +/- 1.9 years underwent anthropometric measurements for determination of regional and total body fat (BMI, waist to hip ratio [WHR], computed tomographic [CT] scan, dual-energy x-ray absorptiometry [DEXA] scan, and bioimpedance analysis [BIA]) before and after 12 months of placebo-controlled GH substitution (2 IU/m2) in a parallel design. The same measurements were performed in 42 healthy adults aged 39.1 +/- 1.7 years. The logarithm of serum leptin levels correlated positively with abdominal subcutaneous fat and total body fat (BIA and DEXA) in untreated GHD patients and healthy subjects. Fasting insulin did not correlate with leptin levels in either of the groups. After 12 months of GH administration, the body composition of GHD patients was significantly changed with respect to a marked decrease in body fat. The relations of leptin to the estimates of body fat were maintained, and leptin was furthermore related to BMI and fasting insulin. In multiple linear regression analyses, additional estimates of visceral adiposity (intraabdominal fat and maximal anterior-posterior diameter determined by CT scan) were significant determinants of leptin in the healthy subjects. The increase in fasting insulin levels during GH substitution correlated negatively with the reduction in leptin levels (r = -.823, P = .003). At baseline, leptin levels were increased in the patients compared with controls in both sexes (women, 21.8 +/- 3.3 v 11.3 +/- 1.4 ng/mL, P = .002; men, 8.1 +/- 1.2 v 4.7 +/- 0.7 ng/mL, P = .008). Leptin levels were similar in GHD patients treated for 12 months compared with healthy controls for both women and men (women, 15.9 +/- 2.3 and 11.3 +/- 1.4 ng/mL, P = .163; men, 7.1 +/- 2.8 and 4.7 +/- 0.7 ng/mL, P = .759). In healthy adults and in GHD patients, leptin levels were significantly higher in women than in men (11.3 +/- 1.4 v 4.7 +/- 0.7 ng/mL, P < .001; 21.8 +/- 3.3 v 8.1 +/- 1.2 ng/mL, P < .001). Gender remained a significant determinant of leptin levels in several models of multiple linear regression analysis also including age, estradiol levels, insulin, and estimates of body fat. We conclude that leptin is increased but not differently regulated in GHD patients compared with normal subjects, and that leptin levels are closely related to estimates of body fat. This relationship is maintained during a decrease in body fat due to GH substitution.

Absorptiometry, Photon↗

PubMed1999

Bioavailability of lysine from a liquid lysine source in chicks.

Two experiments were conducted to assess the bioavailability of lysine from a liquid lysine product (LLP; 60% lysine) relative to crystalline L-lysine.HCl. In the first experiment, four groups of five chicks were fed a lysine-deficient basal diet containing corn, soybean meal, and feather meal or the basal diet supplemented with 0.1 or 0.2% lysine from L-lysine.HCl or LLP from Day 8 to 22 posthatching. Weight gain and feed efficiency responded linearly (P < 0.01) to increasing levels of lysine from either lysine source, and multiple linear regression analysis of weight gain regressed on supplemental lysine intake indicated no difference (P > 0.05) in the response to lysine from L-lysine.HCl or LLP. Experiment 2 was conducted using a lysine-deficient basal diet containing corn, peanut meal, and feather meal, and all diets were fed to five groups of five chicks from Day 8 to 21 posthatching. Treatment additions again consisted of 0.1 or 0.2% lysine from L-lysine.HCl or LLP. Weight gain and feed efficiency responded linearly (P < 0.01) to increasing levels of lysine from L-lysine-HCl and LLP, and multiple linear regression analysis of weight gain regressed on supplemental lysine intake indicated no difference (P > 0.05) in the response to lysine from L-lysine.HCl or LLP. These data indicate that lysine from LLP is fully bioavailable relative to lysine from crystalline L-lysine.HCl, and could therefore be used as a source of lysine in practical poultry diets.

Animal Feed↗

PubMed1991

When is a diagnosis worth making? A statistical comparison of two prediction strategies.

For a setting in which the sole goal is to predict a criterion accurately, two strategies are compared, (1) multiple linear regression directly from a set of predictors and (2) using predictors to diagnose individuals and then using only the diagnosis to predict the criterion. These are mathematical models of two common methods for making clinical predictions. This article derives equations for each statistical strategy's validity (and a formula comparing them, for a special case). Prediction accuracies are compared over a simplified but broad parameter space and four conclusions follow. Changing disorder prevalences (in the range 0.1 to 0.5) have small effect on the relative preferability of the two strategies; the effect of varying prevalence differs according to population separation on predictors and criterion. As within-population covariances of predictors with criterion decline below zero (assuming variables are scaled so that the less common population scores higher on predictors and criterion), diagnoses become increasingly preferable as a prediction strategy; as they rise above zero the opposite trend is observed. As populations become better separated on predictors or criterion, diagnoses compare more favorably. Most importantly, over almost all of the parameter space which one would expect to encounter in clinical psychology and psychiatry, multiple linear regression is much superior.

Diagnosis, Differential↗

PubMed1998

Longitudinal health endangering behavior risk among resilient and nonresilient early adolescents.

PURPOSE: To explore the relative likelihood of engaging in new health-endangering behaviors among a group of resilient early adolescents compared to a sample of nonresilient peers and a sample of normal, low-risk peers in a nonclinical, school-based setting. METHODS: Resilient adolescents and their peer groups were identified by way of a multiple linear regression equation in which age, family structure (single or step-parent family), gender, self-injurious behaviors, and emotional risk were used to predict propensity to initiate risky health behaviors. The resilient sample consisted of those adolescents who were predicted to be above the standardized mean, yet actually scored below it. The nonresilient population included those who were predicted to and actually scored above the standardized mean. The normal, low-risk population consists of adolescents who were predicted to and scored below the standardized mean. The mean age for all populations was 13.78 years. All students completed a Health Behavior Questionnaire and the Rosenberg Self-Esteem Inventory. RESULTS: Odds ratios with 95% confidence intervals revealed that in the year following identification as resilient, nonresilient, or normal, the resilient adolescents were less likely than the nonresilient adolescents to initiate a variety of risky behaviors. At the same time, the resilient adolescents were more likely than their normal, not at-risk peers to have initiated those same risky behaviors. The resilient adolescents have modestly higher mean self-esteem than the nonresilient peers (t = 2.47, p < 0.05) but lower self-esteem than their normal, not at-risk peers (t = 3.66, p < 0.01). CONCLUSIONS: Determination of resilience status by way of multiple linear regression yielded identifiable groups which conformed to expected elevated risk of initiating new risky behaviors relative to normal, not at-risk peers but lowered risk relative to nonresilient peers. Differences were most notable with reference to new reports of substance use. The lower rate of initiating new risky behaviors among resilient relative to nonresilient peers is seen as a reflection of behavioral competence in an adverse context. However, the elevated rate of initiating new risky behaviors among resilient relative to normal, not at-risk peers is seen as a reflection of the continuing, negative impact of that adverse context.

Adolescent↗

PubMed1990

Mechanical and metabolic determinants of myocardial stunning in extracorporeally perfused pig hearts.

The purpose of this study was to apply step-wise multiple linear regression analysis retrospectively to an array of mechanical and metabolic measurements chosen because they had the potential to predict the extent of contractile recovery from a prescribed duration of myocardial ischemia. Data were acquired from the extracorporeally perfused, intact, working pig heart which was rendered regionally ischemic (60% reduction in anterior descending coronary flow) for 45 minutes and reperfused to aerobic levels for a final 30-50 minutes. Mechanical recovery was defined by the percentage systolic shortening and the area circumscribed by left ventricular pressure-segment length loops. Data were taken from 39 control hearts and from 16 hearts treated with oxfenicine, an agent which we have previously used to alter mechanical function by its interference with fatty acid metabolism. Despite the fixed nature of the protocol in affecting ischemic hypoperfusion, a wide range of mechanical responses encompassing hypo- and dyskinesis was produced during ischemia, followed by mechanical stunning during reflow. Of the parameters surveyed, regional indices of mechanical performance, together with perfusate pH and PCO2, best predicted recovery. Along with the heart rate, these predictors gave correlations of 0.875 for percentage systolic shortening and 0.766 for the length-pressure loop in control hearts. The analyses were also sensitive to the influence of pharmacological intervention with oxfenicine in that several parameters lost statistical significance for percentage systolic shortening and two were added (heart rate and end-diastolic length) for the length-pressure loop. Separate statistical models for oxfenicine-treated hearts gave correlations of 0.905 for percentage systolic shortening and 0.915 for the length-pressure loop. The data suggest that step-wise multiple linear regression analysis provides new insights toward our understanding of the mechanisms of mechanical stunning in myocardial reperfusion.

Animals↗

PubMed1996

Development of an experimental diet for determining bioavailable choline concentration and its application in studies with soybean lecithin.

Attempts to determine choline bioavailability have encountered criticism of experimental diets and protocol. Our objectives were to develop a choline-deficient soy isolate diet to quantify bioavailable choline concentration of soybean lecithin and to compare results to those obtained with a purified diet. In Assay 1, weight gain of chicks fed a choline-free crystalline amino acid diet responded linearly (P < .01) to graded doses of choline chloride, fluid lecithin (FL), or deoiled lecithin (DL). Multiple linear regression analysis indicated a bioavailable choline content of 2.3 and 3.7% for FL and DL, respectively. In Assay 2, a choline-deficient soy isolate diet was supplemented with 2-amino-2-methyl-1-propanol (AMP) to inhibit choline biosynthesis. Weight gain, feed intake, and feed efficiency increased (P < .05) markedly with the addition of choline chloride, but supplemental methionine or betaine had no effect (P > .10). Addition of 10% soybean meal to the diet severely deficient in choline per se produced a growth response (P < .05), whereas the same addition to the diet made adequate in choline did not elicit a growth response. In Assay 3, addition of graded levels of choline chloride, FL, or DL to the choline-deficient soy isolate diet containing AMP resulted in a linear (P < .01) increase in weight gain and feed intake. Multiple linear regression analysis indicated a bioavailable choline content of 2.0 and 3.5% for FL and DL, respectively. The AMP-containing soy isolate diet seems well suited for determination of bioavailable choline content in products containing secondary nutrients. Bioavailable choline content of FL and DL was similar to estimates of total choline content, suggesting that the choline in these products was fully available.

Animals↗

PubMed1995

Factors associated with weight for height and skinfold thickness in British children.

STUDY OBJECTIVE: To examine the associations of social and biological factors with measures of obesity in children. DESIGN: The study had a cross sectional design. SETTING: The analyses were based on data from two national study of health and growth cross sectional surveys. The "representative sample" comprised 1990 data from 22 English areas and 1990-91 data from 14 Scottish areas; the "inner city sample" comprised 1991 data from 20 English areas. PARTICIPANTS: The subjects were primary school children aged mainly 5-11 years living in England and Scotland. The "representative" sample included 10,628 children--6463 living in England and 4165 living in Scotland. The "inner city" sample included 7049 children--2183 white, 1124 Afro-Caribbean, 2696 Indian subcontinent, and 1046 from other groups. Due to missing values on continuous variables, 8374 children were included in the analyses. MEASUREMENTS AND MAIN RESULTS: The relation between social environment and childhood overweight was studied using several indicators of obesity. Triceps, subscapular, the sum of triceps and subscapular skinfolds, and weight for height were used as dependent variables. The analyses were carried out in two stages. Firstly, multiple linear regression analyses were used to assess the factors associated with dependent variables treated as continuous. Secondly, multiple linear logistic regression analyses were used to examine the association between independent factors and overweight and fatness defined as binary variables. Birth weight, mother's body mass index (BMI), and father's BMI were consistently associated (p < 0.001) in all models and were the variables that contributed most to the explained variation in the dependent variables. In the multiple regression analyses there was a consistent interaction between the effects of ethnic origin and family size on each outcome variable. In the logistic regression analyses the interaction was not significant, and highly significant associations between both overweight and fatness with the number of children were shown. Ethnic group was not significantly associated with overweight but it was with fatness. The strengths of the remaining significant associations were slight and inconsistent in relation to the dependent variables or the type of analysis. CONCLUSION: Very few variables were associated with measures of overweight and fatness. The only useful factor that was highly associated with all measures of fatness was the parents' BMI. Strategies to prevent childhood obesity should be aimed at the total population and special emphasis should be placed on families in which one or both parents are overweight.

Birth Weight↗

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↗

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↗

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↗

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↗

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↗

PubMed1998

Bronchial responsiveness and five-year FEV1 decline: a study in miners and nonminers.

Increased nonspecific bronchial responsiveness (NSBR) may be a risk factor for the development of chronic airflow obstruction. We evaluated this hypothesis in a cohort of 378 underground coal miners and working nonminers. Methacholine testing was performed at the beginning and end of a 5-yr study period. Spirometry was repeated at 6-mo intervals and individual 5-yr FEV1 slopes were calculated by linear regression. Relationships between FEV1 slopes and NSBR were examined using multiple linear regression models, controlling for FEV1 level, smoking, and mining. Increasing NSBR at the initial survey was associated with a somewhat greater rate of subsequent FEV1 decline. Methacholine responders at the final survey had a considerably increased rate of decline during the previous years. Responsiveness status changed over the 5 yr in 22% of the subjects. Both the development and persistence of increased NSBR were strongly associated with higher rates of FEV1 decline. In contrast, FEV1 declines were not accelerated among workers with increased NSBR that reverted to normal. Smoking and mining were both independently associated with FEV1 declines, but did not substantially modify the effect of NSBR. Due to its variability over time, NSBR testing predicts lung function decline only in some individuals, and its value as a prognostic test for chronic airway disorders is limited. Because improvement in bronchial hyperresponsiveness was associated with a reduction in the rate of FEV1 loss, interventions directed at preventing or reducing nonspecific airway hyperresponsiveness should be investigated.

Adult↗