Sex-specific Prediction Equations Research Articles

Oscillometry Reference Values for Children and Adolescents

BackgroundOscillometry devices allow quantification of respiratory function at tidal breathing but device-specific reference equations are scarce: the present study aims to create sex-specific oscillometric reference values for children and adolescents using the Resmon PRO FULL device.MethodsHealthy participants (N=981) aged 6 to 17 years of the Austrian LEAD general population cohort were included. Subjects had normal weight (BMI≤99th percentile) and normal lung volumes (total lung capacity (TLC)≥lower limit of normal). Oscillometry data were collected using a single frequency mode of 8 Hz. Sex-specific prediction equations were developed for total (tot), inspiratory (insp) and expiratory (exp) resistance (R) and reactance (X) as well as for the modulus of impedance (Z) value using the LMS (lambda, mu, sigma) method. Height was used as a single covariate.ResultsReference equations for all oscillometry parameters were created for Caucasian children aged 6 to 17 years with a height span from 101 to 183 cm and a lung volume span from 1.7 L to 8.8 L TLC. R and Z values progressively decrease and X values increase with increasing height. Oscillometry parametersversuslung volume curves differ from thoseversusheight curves. Stratified for lung size, no sex differences are found for oscillometry parameters.ConclusionOur study provides reference values for oscillometry parameters in children and adolescents using strictly defined criteria for weight and lung volumes. No sex related differences in oscillometry parameters corrected for height or lung size are found.

Cardiorespiratory Fitness in Children with Obesity and Respiratory Symptoms

Study Objective: Physical fitness (i.e., VȮ2max in ml/min/kg) is decreased in children with obesity. However, cardiorespiratory fitness (i.e., VȮ2max as a percent of predicted based on ideal body mass) is preserved in children with obesity. Unfortunately, many children with obesity suffer from obesity-related respiratory symptoms such as exertional dyspnea, which could make them reluctant to exercise and thus decrease both their physical fitness and cardiorespiratory fitness. Thus, we hypothesized that both physical fitness and cardiorespiratory fitness will be decreased in children with obesity and respiratory symptoms. Methods: Body composition (DXA) was measured on children aged 8-12yrs without obesity (‘CWOO’; n=25; 15th≤BMI≤85th percentile), with obesity (‘CWO’; n=49; BMI≥95th percentile), and with obesity and respiratory symptoms (‘CWORS’; n=14; BMI≥95th percentile). On a separate day, participants completed an incremental exercise test to volitional exhaustion. After 15min of seated rest, participants then performed a constant-load supramaximal verification test at 105% of the peak work rate. The highest VȮ2 from the incremental or verification test was recorded as VȮ2max. BMI-for-age data from the CDC were used to calculate ‘ideal’ body mass (BM) at the 50th percentile for CWO, CWORS, and CWOO who were above the 50th BMI percentile. Percent predicted VȮ2max was calculated using sex-specific prediction equations developed by Cooper et al. (2016). A one-way ANOVA with post hoc tests was used to determine differences among groups (i.e., CWOO, CWO, and CWORS). Significance was set at p < 0.05. Results: Age in years was slightly but significantly greater in CWOO (11.0±1.1) vs. CWORS (10.2±1.1), but similar between CWO (10.4±1.3) and the other two groups. Height was not significantly different between groups. BM in kg was similar between CWO (60.18±15.65) and CWORS (63.16±13.10), and significantly higher than CWOO (39.18±7.11). There were no significant differences in BMI (% of the 95th percentile), fat mass, % fat, or circumference measures between CWO and CWORS. VȮ2max in L/min was not different between groups (CWOO, 1.48±0.35; CWO, 1.59±0.32; CWORS, 1.57±0.30). VȮ2max in % predicted was not different between groups (CWOO, 97±12; CWO, 96±12; CWORS, 91±12). VȮ2max in ml/min/kg was similar between CWO (27.0±3.7) and CWORS (25.2±3.5), but significantly greater in CWOO (37.9±7.1) vs. the other two groups. Conclusion: Cardiorespiratory fitness is not affected in children with obesity and respiratory symptoms. Thus, the origin of symptoms in children with obesity and respiratory symptoms is probably not related to deconditioning. These findings are important to inform healthcare providers who examine fitness and associations with chronic disease in children with obesity. NIH R01 HL136643, King Charitable Foundation Trust, Cain Foundation, unrestricted gift from Dr. Pepper Snapple, and Texas Health Presbyterian Hospital Dallas. Dr. Daniel Wilhite was funded by an NIH Administrative Supplement to Promote Diversity in Health-Related Research (HL136643-01S1). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Prediction of incident chronic kidney disease in a population with normal renal function and normo-proteinuria.

Regarding the irreversible clinical course of chronic kidney disease, identifying high-risk subjects susceptible to Chronic Kidney Disease (CKD) has an important clinical implication. Previous studies have developed risk prediction models identifying high-risk individuals within a group, including those who may have experienced minor renal damage, to provide an opportunity for initiating therapies or interventions at earlier stages of CKD. To date, there were no other studies developed a prediction model with quantitative risk factors to detect the earliest stage of CKD that individuals with normal renal function in the general population may experience. We derived 11,495,668 individuals with an estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m2 and normo-proteinuria, who underwent health screening ≥2 times between 2009 and 2016 from the prospective nationwide registry cohort. The primary outcome was the incident CKD, defined by an eGFR <60 mL/min/1.73 m2. Sex-specific multivariate Cox regression models predicting the 8-year incident CKD risk were developed. The performance of developed models was assessed using Harrell's C and the area under the receiver operating characteristics curve (AUROC) with 10-fold cross-validation. Both men and women, who met the definition of incident CKD, were older and had more medical treatment history in hypertension and diabetes. Harrell's C and AUROC of the developed prediction models were 0.82 and 0.83 for men and 0.79 and 0.80 for women. This study developed sex-specific prediction equations with reasonable performance in a population with normal renal function.

How Does Lower-Body and Upper-Body Strength Relate to Maximum Split Jerk Performance?

Soriano, MA, Jiménez-Ormeño, E, Amaro-Gahete, FJ, Haff, GG, and Comfort, P. How does lower-body and upper-body strength relate to maximum split jerk performance? J Strength Cond Res 36(8): 2102-2107, 2022-The aims of this study were to (I) determine the relationships between the maximum dynamic strength of the upper and lower body, measured by overhead press and back squat 1 repetition maximum (1RM) performances, and the split jerk (SJ) performance in trained weightlifters and (II) explore the magnitude of these relationships for men and women to establish sex-specific prediction equations. Twenty men (age: 28.9 ± 6.6 years; height: 1.8 ± 0.1 m; body mass [BM]: 82.5 ± 10.2 kg; weightlifting training experience: 4.2 ± 2.4 years) and 13 women (age: 27.7 ± 4.4 years; height: 1.7 ± 0.1 m; BM: 61.8 ± 5.2 kg; weightlifting training experience: 2.7 ± 1.7 years) competitive weightlifters participated. The 1RM performances of the overhead press, back squat, and SJ were assessed for all subjects. A very strong correlation exists between the back squat and overhead press, with maximum SJ performance for all subjects (r = 0.97; p < 0.001). Similarly, very strong correlations were found for men (r = 0.90, p < 0.001) and women (r = 0.90, p = 0.0002), separately. The coefficient of determination indicates that the prediction equation for the maximum SJ performance is quite accurate (R2 = 0.94) for all subjects and men (R2 = 0.83) and women (R2 = 0.81), separately. These results provide evidence that the maximum strength of the upper and lower body are major contributors to SJ performance. In addition, SJ performance can accurately be predicted from the back squat and overhead press performances.

Maximal Static Respiratory and Sniff Pressures in Healthy Children. A Systematic Review and Meta-Analysis.

Respiratory muscle strength in children can be assessed by maximal inspiratory pressures (MIP), maximal expiratory pressures (MEP), and sniff nasal inspiratory pressures (SNIP). However, previous studies involved small cohorts of healthy children and reported wide reference ranges. To perform a systematic review to summarize existing reference ranges for MIP, MEP, and SNIP tests in healthy children and to conduct a meta-analysis to develop comprehensive prediction equations. Five databases were searched for relevant studies from database inception to May 29, 2017. Study inclusion was limited to publications that evaluated MIP, MEP, and SNIP values in healthy children aged 18 years or younger. Studies were also excluded if testing methodology differed greatly from the 2002 American Thoracic Society Statement on Respiratory Muscle Testing. Requests for raw data were made to authors via e-mail. A total of 18 studies including 3,509 children were systematically reviewed. Diagnostic accuracy of the included studies was assessed using the QUADAS-2 tool, which revealed a high risk of bias for flow and timing and for applicability that may influence the generalizability of our findings. All 18 studies evaluated respiratory pressures in children in seated position. MIP tests were conducted from residual volume, MEP tests from total lung capacity, and SNIP tests from functional residual capacity. The MIP and MEP values in three age groups for boys and girls were summarized using meta-analysis based on individual participant data from five studies containing 1,709 healthy children. Further analyses showed that MIP and MEP were significantly greater in boys than in girls (P < 0.0001). In both sexes, MEP values were always greater than MIP values (P < 0.05). Multivariable random effects models were then performed to establish sex-specific prediction equations. These equations found age, height, and weight to be significant predictor variables. Only two studies with SNIP values from healthy children were included in the review, but they were not part of the meta-analysis. We summarized the available reference ranges for MIP, MEP, and SNIP tests based on existing literature, especially for three age groups, and developed prediction equations that can be used in pulmonary function laboratories to aid clinicians. Existing literature on SNIP tests is limited, and future studies are encouraged to explore their use in children. Systematic review registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42017072004).

The Effect of New Formulas for Lean Body Mass on Lean-Body-Mass–Normalized SUV in Oncologic 18F-FDG PET/CT

Because of better precision and intercompatibility, the use of lean body mass (LBM) as a mass estimate in the calculation of SUV (SUL) has become more common in research and clinical studies today. Thus, the equations deciding this quantity must be those that best represent the actual body composition. Methods: LBM was calculated for 44 patients examined with 18F-FDG PET/CT scans by means of the sex-specific predictive equations of James and Janmahasatians, and the results were validated using a CT-based method that makes use of the eyes-to-thighs CT component of the PET/CT aquisition and segments the voxels according to Hounsfield units. Intraclass correlation coefficients and Bland-Altman plots were used to assess agreement between the various methods. Results: A mean difference of 6.3 kg (limits of agreement, -15.1 to 2.5 kg) between [Formula: see text] and [Formula: see text] was found. This difference was higher than the 3.8-kg difference observed between [Formula: see text] and [Formula: see text] (limits of agreement, -12.5 to 4.9 kg). In addition, [Formula: see text] had a higher intraclass correlation coefficient with [Formula: see text] (0.87; 95% confidence interval, 0.60-0.94) than with [Formula: see text] (0.77; 95% confidence interval, 0.11-0.91). Thus, we obtained better agreement between [Formula: see text] and [Formula: see text] Although there were exceptions, the overall effect on SUL was that [Formula: see text] was greater than [Formula: see text] Conclusion: We have verified the reliability of the suggested [Formula: see text] formulas with a CT-derived reference standard. Compared with the more traditional and available set of [Formula: see text] equations, the [Formula: see text] formulas tend to yield better agreement.

The Andersen aerobic fitness test: New peak oxygen consumption prediction equations in 10 and 16-year olds.

Measurement of aerobic fitness by determining peak oxygen consumption (VO2peak ) is often not feasible in children and adolescents, thus field tests such as the Andersen test are required in many settings, for example in most school-based studies. This study provides cross-validated prediction equations for VO2peak based on the Andersen test in 10 and 16-year-old children. We included 235 children (n=113 10-year olds and 122 16-year olds) who performed the Andersen test and a progressive treadmill test to exhaustion to determine VO2peak . Joint and sex-specific prediction equations were derived and tested in 20 random samples. Performance in terms of systematic (bias) and random error (limits of agreement) was evaluated by means of Bland-Altman plots. Bias varied from -4.28 to 5.25mL/kg/min across testing datasets, sex, and the 2 age groups. Sex-specific equations (mean bias -0.42 to 0.16mL/kg/min) performed somewhat better than joint equations (-1.07 to 0.84mL/kg/min). Limits of agreement were substantial across all datasets, sex, and both age groups, but were slightly lower in 16-year olds (5.84-13.29mL/kg/min) compared to 10-year olds (9.60-15.15mL/kg/min). We suggest the presented equations can be used to predict VO2peak from the Andersen test performance in children and adolescents on a group level. Although the Andersen test appears to be a good measure of aerobic fitness, researchers should interpret cross-sectional individual-level predictions of VO2peak with caution due to large random measurement errors.

Body composition by dual-energy X-ray spectrometry and bioelectrical impedance spectroscopy in a healthy population at age 75 and 80

Bioelectrical impedance spectroscopy (BIS) is a versatile field tool to obtain information about body composition (BC), if prediction equations are available that are valid for the group under consideration. We aimed to validate prediction equations for total body skeletal muscle mass (TBSMM) developed in healthy 75-year olds from the Gothenburg area (Sweden) in a similar sample examined at age 80. We give new prediction equations for fat mass (FM), fat-free mass (FFM), and TBSMM that are based on the entire group of elderly subjects, using values from Dual-energy X-ray spectrometry (DXA) as reference standard. Finally, we describe the longitudinal change in BC in the subset of subjects, who participated at both age 75 and 80. Body composition was measured by DXA and multiple-frequency BIS at age 75 (n=111) and 80 (n=91) years. Ordinary and mixed linear regression was used to examine previous and new prediction equations. Longitudinal change was assessed by paired sample t-test. The prediction equations for TBSMM developed in 75-year old subjects showed good validity when applied to the sample of 80 year olds. The results were independent of the presence of a metal prosthesis in hip or knee. New, sex-specific prediction equations for FM, FFM, and TBSMM were derived for 75 - 80 year-old subjects that further improved the accuracy of prediction. Using DXA-derived BC at ages 75 and 80, we observed a decline in TBSMM in both sexes, which was mainly due to muscle loss in the legs. In men, the decrease in trunk FFM was accompanied by an increase in FM, leaving no overall weight change in the trunk. When the 5-year change in TBSMM was based on longitudinal BIS measurements, the results from DXA were reproduced only when the prediction was based on BIS-values at 50kHz. Good cross-sectional validity of BIS equations for TBSMM was found in a population sample of 80-year olds. The presence of a metal prosthesis did not influence the quality of prediction. New prediction equations for FM, FFM, and TBSMM need to be evaluated in an independent sample.

The oxygen uptake efficiency slope in 1411 Caucasian healthy men and women aged 20-60 years: reference values.

The oxygen uptake efficiency slope (OUES) has been proposed as an independent, reproducible and objective measure of cardiorespiratory function that does not require maximal exercise testing. Existing reference values have been published for healthy paediatric populations and healthy elderly. However, reference ranges and equations for healthy adults of working age are insufficiently documented. The aim of the present study was to establish prediction equations and to describe reference values for healthy men and women aged 20-60 years. Cross-sectional study. One thousand four hundred and eleven (877 men) healthy individuals (mean age 38.6 years; range 20-60) completed a maximal graded cycle exercise test until volitional exhaustion. Subsequently, oxygen uptake was plotted against the logarithm of total ventilation and the OUES was calculated by means of linear regression analysis. Multivariate regression analyses revealed age, sex and body surface area as statistically significant determinants of the OUES. Following this, sex-specific prediction equations for the OUES were established and cross-validated. Finally, the distribution of the OUES with age was described and reference values were established for men and women separately. This study established a comprehensive set of reference values and reference equations for the OUES for a healthy population of men and women aged between 20 and 60 years.

Prediction of Thoracic Dimensions and Spine Length On the Basis of Individual Pelvic Dimensions

Retrospective review. To validate the pelvic inlet width (PIW) measurement obtained on radiograph as an independent standard used to correlate with thoracic dimensions (TDs) in treated and untreated patients with early-onset scoliosis. In children with early-onset scoliosis, the change in TD and spine length is a key treatment goal. Quantifying this change is confounded by varied growth rates and differing diagnoses. PIW measured on computed tomographic (CT) scan in patients without scoliosis has been shown to correlate with TD in an age-independent manner. The first arm included 49 patients with scoliosis who had both a CT scan and pelvic radiograph. Agreement between PIW measurements on CT scan and radiograph was analyzed. The second arm consisted of 163 patients (age, 0.2-18.7 yr), with minimal spinal deformity (mean Cobb, 9.0°) and radiographs in which PIW was measurable. PIW was compared with previously published CT-based TD measurements; maximal chest width, T1-T12 height, and T1-S1 height. Linear regression analysis was used to develop and validate sex-specific predictive equations for each TD measurement on the basis of PIW. Interobserver reliability was evaluated for all measurements. Bland-Altman analysis indicated agreement with no dependence on observed value, but a consistent 8.5 mm (95% CI: 7.2-9.9 mm) difference in CT scan measurement compared with radiographical PIW measurement. Sex and PIW were significantly correlated to each TD measurement (P < 0.01). Predictive models were validated and may be used to estimate TD measurements on the basis of sex and radiographical PIW. Intraclass correlation coefficients for all measurements were between 0.978 and 0.997. PIW on radiographs and CT scan correlate in patients with deformity and with spine and TD in patients with minimal deformity. It is a fast, reliable method of assessing growth while lowering patient's radiation exposure. It can be reliably used to assess patients with early-onset scoliosis and the impact surgical treatment has on chest and spinal growth. 3.

Anthropometric estimates of total and regional body fat in children aged 6–17 years

To develop prediction equations for total and regional (trunk, abdominal, arms and legs) body fat using surface anthropometric measures in children aged 6-17 years. This was a cross-sectional correlation study of 70 Caucasian children aged 6-17 years recruited from a larger randomly sampled population-based study. The independent variables included age, mass, height, body mass index, waist and hip girth, and skinfold thicknesses at eight sites. Subscapular/triceps skinfold ratio was also calculated and entered as an independent variable. The dependent variables were total body percentage fat, and fat mass for total body, trunk, abdominal region of interest, arms and legs measured using dual-energy X-ray absorptiometry (DXA). Partial least squares regression was used to determine the best predictive equation for fat percentage or fat mass in each body region in each sex. Sex-specific prediction equations were developed with high coefficients of determination (r(2)), ranging from 0.869 to 0.936 in boys and from 0.900 to 0.979 in girls, absolute bias was low, and limits of agreement were narrow. Equations were developed, which were able to predict total and regional body fat of Caucasian children aged 6-17 years using surface anthropometric measurements with high predictive accuracy.

Lung function reference values in different German populations

Spirometry is a frequently performed lung function test and an important tool in medical surveillance examinations of pulmonary diseases. The interpretation of lung function relies on the comparison to reference values derived from a healthy population. The study aim was to compare the lung function data of three representative population-based German studies (Study of Health in Pomerania [SHIP-1], Cooperative Health Research in the Region of Augsburg [KORA-S3] and European Community Respiratory Health Survey Erfurt [ECRHS-I Erfurt]) with existing European spirometry reference values and to establish a new set of comprehensive German prediction equations. Spirometry was performed in 4133 participants of three population-based surveys using almost identical standardised methods. Current and former smokers, subjects with cardiopulmonary disorders or on medication with potential influence on lung function were excluded. Sex specific prediction equations were established by quantile regression analyses. Comparison was performed to existing European reference values. The healthy reference sample consisted of 1302 (516 male) individuals, aged 20-80 years. Sex specific comprehensive prediction equations adjusted for age and height are provided. Significant differences were found in comparison to previous studies with pronounced lower values of the current population if applying historic prediction equations. The results contribute to the interpretation of lung function examination in providing a comprehensive set of spirometry reference values obtained in a large number of healthy volunteers. Whereas the differences in between the investigated studies are negligible, striking divergence was detected in comparison to historic and recent European spirometry prediction values.

Reference values for respiratory pressures in a general adult population – results of the Study of Health in Pomerania (SHIP)

Respiratory muscle pressures have been gaining increasing interest because of prognostic value. The study aim was to acquire reference values for respiratory pressures in a large-scale population-based survey--the Study of Health in Pomerania (SHIP). One thousand eight hundred and nine participants (885 men) of a cross-sectional epidemiologic survey, called 'Study of Health in Pomerania--SHIP', underwent lung function and respiratory muscle pressure measurements. After excluding individuals with cardiopulmonary disorders, prediction equations for men and women were established by quantile regression analysis. The final study population comprised 912 individuals (432 men), aged 25-80 years. The study provides a representative set of sex-specific prediction equations of respiratory muscle strength. Respiratory pressures are decreasing with age and are lower in women when compared to men. Prediction equations for relevant respiratory pressures are given. Based on this well-described population-based survey with extensive cardiopulmonary investigations to exclude relevant interfering disorders a sufficient comprehensive set of reference values was obtained.

Determination of height, weight, body mass index, and body surface area with a single abdominal CT image.

Techniques for estimation of an individual's height, weight, body mass index (BMI), and body surface area (BSA) with a single abdominal computed tomographic (CT) image were developed. Eighty-seven abdominal CT examinations performed in adult humans were analyzed. Anatomic structures were outlined on the CT section that included L1. Multiple linear regression analysis was used to derive sex-specific predictive equations. Correlation for height was good (r > 0.65). Relationship between predicted weight and actual weight was good (r > 0.93). For BMI and BSA, r was greater than 0.893 and greater than 0.895, respectively. In this study, predictive equations for height, weight, BMI, and BSA were generated.

Development of airway function in infancy after preterm delivery

Objective: To assess airway function at 1 year and compare this with similar measurements made shortly after birth in preterm infants without clinical neonatal respiratory disease. Study design: Infants born at ≤36 weeks' gestational age were eligible if they required no neonatal ventilatory support and were otherwise healthy. Paired measurements of maximal expiratory flow at functional residual capacity (V′maxFRC) were obtained ~3 weeks after birth in 24 preterm infants (gestational age [mean ± SD], 33.2 ± 2.2 weeks) and repeated at a corrected postnatal age (mean ± SD) of 57.0 ± 12.2 weeks. V′maxFRC values were expressed as Z scores by means of sex-specific prediction equations. Results: V′maxFRC was within normal range for all infants shortly after birth (mean ± SD Z score: −0.06 ± 0.92). By 1 year, Z scores had reduced significantly [mean (95% CI) 2nd-1st test: −1.94 (−2.27, −1.60)]. V′maxFRCZ scores at 3 weeks were highly correlated with those at 1 year of age (Spearman correlation coefficient 0.64). Conclusions: Airway function during the first year shows considerable tracking. Even in the absence of neonatal respiratory disease, preterm delivery is associated with altered airway development during early infancy. (J Pediatr 2002;141:652-8)

Sex-specific prediction equations for Vmax(FRC) in infancy: a multicenter collaborative study.

Measurements of maximal flow at functional residual capacity (Vmax(FRC)) from partial forced expiratory maneuvers remain the most popular method for assessing small airway function in infants and young children. However, the lack of appropriate reference data that are both applicable outside the centers that developed them and reflect the normal variability between healthy subjects has limited interpretation of Vmax(FRC) results in both clinical practice and research. To address this problem, we collated Vmax(FRC) data from 459 healthy infants (226 boys) tested on 654 occasions during the first 20 months of life from three collaborating centers. Multiple linear regression analysis indicated that sex, age, and length were important predictors of Vmax (FRC), which was, on average, 20% higher in girls than in boys during the first 9 months of life. (Vmax(FRC))0.5 (ml x second(-1)) = 4.22 + 0.00210 x length2 (cm) for boys (RSD = 3.01; R2 = 0.48), and -1.23 + 0.242 x length for girls (RSD = 2.72; R2 = 0.49). Alternative models incorporating both age and length z scores are also described. Failure to use sex-specific prediction equations for Vmax(FRC) may preclude detection of clinically significant changes in girls and lead to false reports of diminished airway function in boys. Appropriate use of z scores, which indicate a "normal" range (z scores of 0 +/- 2) for Vmax(FRC), during infancy should also improve interpretation of both clinical and research studies.

A stroke prediction score in the elderly: validation and Web-based application

The objective of this study was to construct a prediction model for predicting stroke in an elderly U.S. population, and to assess the accuracy in this population of other previously published prediction models. The subjects were participants in the Cardiovascular Health Study: 2,495 men and 3,393 women age 65 years and older at baseline, and followed for 6.3 years. Among 5,711 participants free of baseline stroke, 399 strokes occurred. Sex-specific prediction equations were constructed using study variables that were most importantly related to incident stroke: age, systolic blood pressure, diabetes, ECG diagnosis of atrial fibrillation or left ventricular hypertrophy, confirmed history of cardiovascular disease, diabetes, time to walk 15 ft, and serum creatinine. The prediction rule was implemented as a risk score and in a Web-based interactive Java applet. Overall, the model predicted 5-year stroke risks ranging from less than 1 to 59%. The 20% of subjects in the highest predicted risk group had a 5-year actual stroke incidence rate of 15%, while the 20% lowest risk group had a 1% incidence. Risk scores from two other studies performed well in these study participants. Effective discrimination between low and high stroke risk in the elderly was possible in this cohort with data that are easy to obtain. Evaluation of the generalizability and clinical usefulness of this prediction model requires further research.

The prediction of height by armspan in older Chinese people

Objective : To compare the accuracy of the predictive equations derived from older Chinese people without vertebral deformity with those derived from unselected older people, in estimating height from armspan. Methodology : Height and armspan were measured in 789 older Chinese and 885 young Chinese in Hong Kong. All the older subjects had spinal X-ray (T4 to L4). Vertebral deformity was determined by a trained technician using a translucent digital analyser. Definite deformity was defined by a greater than 3 standard deviation increase in one of the three vertebral height ratios (anterior/posterior, middle/posterior and posterior/posterior). Eighty of the older subjects without vertebral deformity were randomly selected from the studied population for internal validation of predictive equations. The remaining subjects were used to derive sex-specific predictive equations for height by linear regression against armspan. The accuracy of these equations was analysed by the Bland and Altman method. Results : Vertebral deformity was present in 30.7% and 15.6% of older female and male subjects, respectively. Older women without vertebral deformity had significantly greater armspan: height ratio when compared with the young (1.04 versus 1.02), but the corresponding ratios were the same in older and young men (both 1.04). The predictive equation derived from older females without vertebral deformity had lower standard error of estimation and gave estimates closer to measured height than those derived from unselected older women. But this was not the case in older men. Conclusion : In deriving predictive equation to estimate height by armspan in older Chinese women, selecting out older women without vertebral deformity increased accuracy of the equation. This was, however, not the case in older men.

Prediction of Coronary Heart Disease Using Risk Factor Categories

The objective of this study was to examine the association of Joint National Committee (JNC-V) blood pressure and National Cholesterol Education Program (NCEP) cholesterol categories with coronary heart disease (CHD) risk, to incorporate them into coronary prediction algorithms, and to compare the discrimination properties of this approach with other noncategorical prediction functions. This work was designed as a prospective, single-center study in the setting of a community-based cohort. The patients were 2489 men and 2856 women 30 to 74 years old at baseline with 12 years of follow-up. During the 12 years of follow-up, a total of 383 men and 227 women developed CHD, which was significantly associated with categories of blood pressure, total cholesterol, LDL cholesterol, and HDL cholesterol (all P<.001). Sex-specific prediction equations were formulated to predict CHD risk according to age, diabetes, smoking, JNC-V blood pressure categories, and NCEP total cholesterol and LDL cholesterol categories. The accuracy of this categorical approach was found to be comparable to CHD prediction when the continuous variables themselves were used. After adjustment for other factors, approximately 28% of CHD events in men and 29% in women were attributable to blood pressure levels that exceeded high normal (> or =130/85). The corresponding multivariable-adjusted attributable risk percent associated with elevated total cholesterol (> or =200 mg/dL) was 27% in men and 34% in women. Recommended guidelines of blood pressure, total cholesterol, and LDL cholesterol effectively predict CHD risk in a middle-aged white population sample. A simple coronary disease prediction algorithm was developed using categorical variables, which allows physicians to predict multivariate CHD risk in patients without overt CHD.

Body compartment and subcutaneous adipose tissue distribution--risk factor patterns in obese subjects.

The purpose of this study was to investigate whether upper body obesity and/or visceral obesity are related to cardiovascular risk factors among severely obese subjects, phenomena that have previously been reported in more heterogeneous body weight distributions. 2450 severely obese men and women aged 37 to 59 years, with a body mass index of 39 +/- 4.5 kg/m2 (mean +/- SD) were examined cross-sectionally. Eight cardiovascular risk factors were studied in relation to the following body composition indicators: four trunk and three limb circumferences, along with weight, height and sagittal trunk diameter. From the latter three measurements lean body mass (LBM, i.e., the non-adipose tissue mass) and the masses of subcutaneous and visceral adipose tissue were estimated by using sex-specific prediction equations previously calibrated by computed tomography. Two risk factor patterns could be distinguished: 1. One body compartment-risk factor pattern in which the subcutaneous adipose tissue (AT) mass and, in particular, the visceral AT mass were positively related to most risk factors while the lean body mass was negatively related to some risk factors. 2. One subcutaneous adipose tissue distribution- risk factor pattern in which the neck circumference was positively and the thigh circumference negatively related to several risk factors. It is concluded that lean body mass (LBM), visceral and subcutaneous adipose tissue masses as well as neck and thigh circumferences, used as indices of subcutaneous adipose tissue distribution, are independently related to cardiovascular risk factors in severely obese men and women.