Fracture risk in children with a forearm injury is associated with volumetric bone density and cortical area (by peripheral QCT) and areal bone density (by DXA).

UNLABELLED: Children who sustain a forearm fracture when injured have lower bone density throughout their skeleton, and have a smaller cortical area and a lower strength index in their radius. Odds ratios per SD decrease in bone characteristics measured by peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) were similar (1.28 to 1.41). INTRODUCTION: Forearm fractures are common in children. Bone strength is affected by bone mineral density (BMD) and bone geometry, including cross-sectional dimensions and distribution of mineral. Our objective was to identify bone characteristics that differed between children who sustained a forearm fracture compared to those who did not fracture when injured. METHODS: Children (5-16 years) with a forearm fracture (cases, n = 224) and injured controls without fracture (n = 200) were enrolled 28 ± 8 days following injury. Peripheral QCT scans of the radius (4% and 20% sites) were obtained to measure volumetric BMD (vBMD) of total, trabecular and cortical bone compartments, and bone geometry (area, cortical thickness, and strength strain index [SSI]). DXA scans (forearm, spine, and hip) were obtained to measure areal BMD (aBMD) and bone area. Receiver operating characteristic (ROC) analyses were used to assess screening performance of bone measurements. RESULTS: At the 4% pQCT site, total vBMD, but not trabecular vBMD or bone area, was lower (-3.4%; p = 0.02) in cases than controls. At the 20% site, cases had lower cortical vBMD (-0.9%), cortical area (-2.8%), and SSI (-4.6%) (p < 0.05). aBMD, but not bone area, at the 1/3 radius, spine, and hip were 2.7-3.3% lower for cases (p < 0.01). Odds ratios per 1 SD decrease in bone measures (1.28-1.41) and areas under the ROC curves (0.56-0.59) were similar for all bone measures. CONCLUSIONS: Low vBMD, aBMD, cortical area, and SSI of the distal radius were associated with an increased fracture risk. Interventions to increase these characteristics are needed to help reduce forearm fracture occurrence.

Predictability of the clinical course of juvenile dermatomyositis based on initial muscle biopsy: a retrospective study of 72 patients.

OBJECTIVE: Except when the diagnosis of juvenile dermatomyositis (DM) is in doubt, a case has not been made for routine muscle biopsy (MB). We sought to determine whether MB findings prior to systemic therapy have prognostic value. METHODS: We reviewed the hospital records and slides prepared from the initial open MB of 72 patients treated at one center between 1977 and 2002 and followed for a minimum of 2 years. None of the patients had received a course of systemic corticosteroid therapy at the time of MB. Our approach to MB evaluation was based on recent discussions with muscle pathology experts to develop criteria for assessing inflammation, vasculopathy, myofiber atrophy, regeneration, acute and chronic myopathic change, and stromal changes. Using simple and multivariate logistic regression, we tested each MB parameter for ability to predict outcome using 2 published classification systems. RESULTS: Extensive active myopathic changes (excluding regeneration) and central nuclei without basophilia predicted chronic juvenile DM. Severe arteropathic change, positive arterial direct immunofluorescence, obvious foci of severe capillary loss/endomysial fibrosis, and muscle infarcts predicted chronic juvenile DM, particularly with ulceration. Other MB parameters, regardless of severity, were not significant predictors of chronic juvenile DM versus limited disease. CONCLUSION: A scoring system for evaluating pretreatment MB in juvenile DM that focuses on extent of necrotizing myopathy, severity of vasculopathy, and features of established chronicity such as central nucleation of nonbasophilic myofibers may provide a basis for stratification of therapeutic regimens according to risk for chronic disease. The validity of our findings should be prospectively tested.

Topical mitomycin application after laryngotracheal reconstruction: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To explore the effect of mitomycin treatment on the pediatric airway following laryngotracheal reconstruction. DESIGN: Randomized, double-blind, placebo-controlled trial. PATIENTS: Children aged 2 to 17 years with subglottic or upper tracheal stenosis undergoing laryngotracheal reconstruction at a single, tertiary care, children's hospital. INTERVENTION: At the time of extubation or stent removal, the children underwent bronchoscopy and 0.4 mg/mL (2 mL of a 0.2-mg/mL solution of either mitomycin or an equal volume of isotonic sodium chloride was directly applied to the subglottic region for a single application of 2 minutes. These children then underwent interval endoscopy at 2 weeks, 6 weeks, and 3 months postoperatively for assessment of their airways. RESULTS: Granulation tissue was graded on a scale of 0 (none) to 4 (near-total or total occlusion). Videotapes of endoscopies were independently observed and graded by 3 pediatric otolaryngology fellows with a subsequent interobserver agreement of 91.6%. The results were then dichotomized to represent a single cohort in which further surgical intervention would be required and another separate cohort in which further surgery would not be required. At the 1-year mark, interim analysis was performed by a Data Safety and Monitoring Committee. At this time, 13 children had been randomized to the mitomycin-treated arm of the study and 11 children to the placebo-treated arm. A 2-tailed Fisher exact test revealed a value of 1.00. The Data Monitoring and Safety Committee advised that the trial should be stopped because the distributions between the 2 populations were almost identical. CONCLUSION: We cannot reject the null hypothesis that a single topical dose of mitomycin exerts an equal benefit as does isotonic sodium chloride when applied to the pediatric airway after laryngotracheal reconstruction.

Relationship between EMG and muscle force after spinal cord injury.

OBJECTIVE: The purpose of this study was to compare the electromyography (EMG) score during contraction of a given muscle to the independently measured manual muscle test (MMT) score for that same muscle (or muscle group), to determine whether EMG measures could serve as a reasonable approximation of muscle contraction force in persons with acute spinal cord injury (SCI). METHODS: We examined the strength of relationship between surface-recorded EMG and estimated muscle strength using the MMT in a population of 45 subjects with acute (<1 week) traumatic SCI. Eight different muscle groups were compared in each individual; measures were repeated on these subjects approximately 2 months later. A 6-point numeric index was used for assignment of EMG scores, all of which were done in a blinded fashion by 1 investigator from tape-recorded evaluations. RESULTS: Nearly all of the individual muscle comparisons led to positive and significant (P < .01) correlations between EMG and MMT scores, at both the acute and subacute time points following injury. CONCLUSIONS: These findings support the use of EMG scoring as an indicator of recovery of volitional strength following SCI in a given subject. However, caution must be used when attempting to extrapolate EMG scores to absolute forces or when comparing EMG scores among different subjects.

Pilot detection study of alpha(1) antitrypsin deficiency in a targeted population.

Screenings for the genetic disorder alpha(1) antitrypsin deficiency (AAT Deficiency) have been one of two models: large screenings of general populations and small targeted detection programs in high-risk groups. The most appropriate screening and detection methodologies in terms of target populations, subject participation and yield of positive tests, however, have not been well defined. The major objective of this pilot study was to evaluate the effectiveness in terms of participation of two different AAT Deficiency detection programs using a self-administered fingerstick blood test. Individuals ages 30-60 under the care of a pulmonary physician and with a diagnosis of emphysema, COPD, chronic bronchitis, or bronchiectasis were the targeted population. Participants were offered AAT Deficiency testing in the pulmonary physician's office compared with testing offered through mail. Participation (i.e., frequency of subject participation in the detection program) of two different AAT Deficiency detection programs. Non-participation was due to fear of self-administered testing and research studies; women were more likely to participate than men. Eligible subjects were significantly more likely to participate when offered testing by their pulmonary physician in-office (83%) than mail-only (42%) (P < 0.02). Although self-administered genetic testing is available, highest participation in AAT Deficiency detection program was found when offered directly by the physician. This finding may have implications for screening and detection of other genetic diseases. Future studies need to evaluate the yield (i.e., frequency of positive tests) of these detection methodologies in highly targeted populations.

Pediatric peripherally inserted central catheters: complication rates related to catheter tip location.

OBJECTIVE: To compare complication rates between central venous catheter tip location and noncentral tip location after peripherally inserted central catheter (PICC) placement in children. METHODS: Between 1994 and 1998, data from all children who underwent PICC placement were analyzed. Patient demographics, catheter characteristics, catheter duration, infusate composition, and catheter complications were entered prospectively into a computerized database. Catheter tip locations were determined by fluoroscopy and were defined as central if they resided in the superior vena cava, right atrium, or high inferior vena cava at or above the level of the diaphragm, and as noncentral if located elsewhere. Differences in complication rates between the central and noncentral groups were analyzed. RESULTS: Data from a total of 1266 PICCs were analyzed from 1053 patients with a mean age of 6.49 +/-.2 years (range: 0-45.0 years). Of the 1266 PICCs, 1096 (87%) were central in tip location, and 170 (13%) were noncentral in tip location. The central group had 42 complications of 1096 catheters (3.8%), while the noncentral group had 49 complications of 170 catheters (28.8%). Controlling for patient age, catheter size, gender, and catheter duration with a logistic regression model, there remained a statistically significant increased likelihood of complication in the noncentral group versus the central group (adjusted odds ratio: 8.28; 95% confidence interval: 5.11-13.43). CONCLUSIONS: Centrally placed catheter tips are associated with fewer complications than are noncentrally placed catheter tips. Clinicians should ensure that catheter tips reside centrally after PICC placement in infants and children.

Formation and current results of a patient-organized registry for alpha(1)-antitrypsin deficiency.

BACKGROUND: Significant challenges exist to investigating uncommon illnesses because too few patients are seen at any single clinical center to permit appropriate research studies. Recognizing this impediment to clinical research in alpha(1)-antitrypsin deficiency, the Alpha One Foundation, a patient-organized research foundation, has collaborated with clinician-scientists to organize a voluntary registry of individuals with alpha(1)-antitrypsin deficiency. PURPOSE: To facilitate clinical research in alpha(1)-antitrypsin deficiency by organizing a registry of affected individuals willing to be approached to participate in clinical studies. METHODS: Elements of the Alpha One Foundation Research Network Registry include a Medical and Scientific Advisory Committee, composed of physician-investigators and patient advocates, designated clinical resource centers at medical institutions with expertise in the management of individuals with alpha(1)-antitrypsin deficiency, and a data coordinating center with responsibility for database management and analysis. Questionnaires requesting information about demographic features, alpha(1)-antitrypsin phenotype, smoking history, and health-care utilization were distributed to prospective registrants through the following channels: mailings from the Alpha One Foundation; mailings from the clinical resource centers; and distribution by home-care and pharmaceutical companies. Information from this questionnaire formed the basis of the initial registry database. RESULTS: Between May 1997 and June 1999, 7,789 forms were distributed, and forms were returned by 712 unique registrants. Registrants have the following characteristics: mean (+/- SD) age, 49.3+/-13.2 years; women, 47.7%; white, 96.2%; PI*ZZ phenotype, 70.7%; ex-smokers, 73.3%; COPD patients, 87.2% (emphysema patients, 54.2%; chronic bronchitis patients, 33%); and self-reported liver disease, 6.4%. The mean number of physician visits reported by registrants in the preceding 12 months was 7.8+/-9.4, 59% reported currently receiving IV augmentation therapy, and 35% reported using supplemental oxygen at home. Examples of ongoing research studies using this unique database include: (1) a case-control study to evaluate occupational risk factors for obstructive lung disease in individuals with alpha(1)-antitrypsin deficiency and (2) a study to evaluate the health-care costs for affected individuals. CONCLUSIONS: A registry currently including 712 individuals with alpha(1)-antitrypsin deficiency has been organized through a collaboration between physician-investigators and a patient-organized research foundation. Use of the registry has already facilitated studies that were previously difficult because of the paucity of identifiable study subjects. The registry cohort promises to provide an important resource for future clinical and epidemiologic studies.

Antibody-dependent and -independent protection following intranasal immunization of mice with rotavirus particles.

The ability to elicit protective immune responses after intranasal immunization with rotavirus particles, either with or without the attenuated Escherichia coli heat-labile enterotoxin LT(R192G) as an adjuvant, was examined in the adult mouse model. BALB/c mice were administered one or two inoculations of psoralen/UV-inactivated, triple-layered (tl) or double-layered (dl) purified rotavirus particles. Four weeks after immunization, mice were challenged with the murine rotavirus strain EDIM, and the shedding of rotavirus antigen was quantified. Rotaviruses used for immunization included EDIM and heterotypic simian (RRV), bovine (WC3), and human (89-12) strains. tl EDIM stimulated both systemic and intestinal rotavirus antibody responses and complete protection with as little as one 1-microgram dose. Inclusion of LT(R192G) (10 micrograms) significantly increased rotavirus antibody responses and reduced antigen concentrations needed for full protection. Both dl EDIM and heterotypic dl and tl particles stimulated protection, but they did so less than tl EDIM at comparable concentrations, either with or without LT(R192G). When B-cell-deficient microMt mice were immunized with tl EDIM particles, protection was reduced to levels similar to those induced with dl EDIM and heterotypic particles in BALB/c mice. However, dl EDIM particles induced similar levels of protection in both mouse strains. The protection stimulated by tl or dl EDIM particles was not diminished by CD8 cell depletion prior to immunization in either strain of mice. These results indicate that tl EDIM induced immunity at least partially through responses to its outer capsid proteins, presumably by stimulation of serotype-specific neutralizing antibody. In contrast, the other particles stimulated protection primarily by an antibody-independent mechanism. Finally, depletion of CD8 cells had no effect on protection by either mechanism.

Is fasting leptin associated with insulin resistance among nondiabetic individuals? The Miami Community Health Study.

OBJECTIVE: Whether serum leptin levels are associated with insulin resistance independent of the effects of hyperinsulinemia and adiposity is an important unanswered question. We examined the relationship between the rate of insulin-mediated glucose uptake and serum leptin concentrations among nondiabetic men and women. RESEARCH DESIGN AND METHODS: A cross-sectional analysis was performed among 49 young to middle-aged men and women who participated in the Miami Community Health Study. All participants had measures of insulin resistance (euglycemic-hyperinsulinemic clamp), postchallenge insulin levels, fasting serum leptin levels, and several measures of adiposity. RESULTS: The rate of insulin-mediated glucose uptake (M in milligrams per kilogram per minute) was significantly associated with leptin concentrations in both men (r = -0.83; P < 0.001) and women (r = -0.59; P < 0.001). M was also inversely related to percent body fat and to the 2-h insulin area under the curve (AUC). After covariate adjustment for sex, percent body fat, and AUC, leptin remained a significant correlate of M (P = 0.04). CONCLUSIONS: Cross-sectionally, leptin was significantly associated with insulin resistance in this nondiabetic sample of men and women. There may be a different physiological mechanism to explain the leptin/insulin resistance association apart from the insulin/adiposity link. Confirmatory evidence awaits the results of clinical trials.

Mortality in a cohort of licensed pesticide applicators in Florida.

OBJECTIVES: Although the primary hazard to humans associated with pesticide exposure is acute poisoning, there has been considerable concern surrounding the possibility of cancer and other chronic health effects in humans. Given the huge volume of pesticides now used throughout the world, as well as environmental and food residue contamination leading to chronic low level exposure, the study of possible chronic human health effects is important. METHODS: This was a retrospective cohort study, analysed by general standardised mortality ratio (SMR) of licensed pesticide applicators in Florida compared with the general population of Florida. A cohort of 33,658 (10% female) licensed pesticide applicators assembled through extensive data linkages yielded 1874 deaths with 320,250 person-years from 1 January 1975 to 31 December 1993. RESULTS: The pesticide applicators were consistently and significantly healthier than the general population of Florida. As with many occupational cohorts, the risks of cardiovascular disease and of diseases associated with alcohol and tobacco use were significantly lower, even in the subpopulations--for example, men, women, and licence subcategories. Among male applicators, prostate cancer mortality (SMR 2.38 (95% confidence interval (95% CI) 1.83 to 3.04) was significantly increased. No cases of soft tissue sarcoma were confirmed in this cohort, and non-Hodgkin's lymphoma was not increased. The number of female applicators was small, as were the numbers of deaths. Mortality from cervical cancer and breast cancer was not increased. Additional subcohort and exposure analyses were performed. CONCLUSIONS: Consistent with previous publications on farmers but at odds with current theories about the protective effects of vitamin D, prostate cancer was increased in these pesticide applicators. Female breast cancer was not increased despite theories linking risk of breast cancer with exposure to oestrogen disruptors--such as the organochlorines. The lack of cases of soft tissue sarcoma is at odds with previous publications associating the use of the phenoxy herbicides with an increased risk of these cancers.

Cancer incidence in a cohort of licensed pesticide applicators in Florida.

This study is a standardized incidence ratio (SIR) analysis of cancer incidence of licensed pesticide applicators in Florida, compared with that of Florida's general population. Through extensive data linkages, 33,658 applicators were assembled who had 1266 incident cancers and 279,397 person-years from January 1, 1975, to December 31, 1993. Disease risk from ethanol and tobacco use were significantly decreased. Among males, prostate cancer (SIR = 1.91; 95% confidence interval [CI], 1.72-2.13) and testicular cancer (SIR = 2.48; 95% CI, 1.57-3.72) were significantly elevated. No confirmed cases of soft tissue sarcoma (STS) were found, and the incidence of non-Hodgkin's lymphoma was not increased. There were few female applicators; nevertheless, cervical cancer incidence (SIR = 3.69; 95% CI, 1.84-6.61) was significantly increased, while the incidence of breast cancer was significantly decreased. Cancers that have been associated with estrogen disrupters were found in male, but not female, pesticide applicators. The lack of soft tissue sarcoma is at odds with prior literature associated with the use of phenoxy herbicides.

Cigarette smoking, alcohol use, and physical activity in relation to serum leptin levels in a multiethnic population: The Miami Community Health Study.

PURPOSE: To examine the correlates of plasma leptin, including fasting insulin, adiposity, and several health habits and behaviors among a nondiabetic multiethnic population. METHODS: A cross-sectional study was conducted among 25-44 year old African-Americans (n = 126), Cuban-Americans (n = 107), and non-Hispanic whites (n = 189) randomly selected from Dade County Florida. Fasting leptin levels were correlated with fasting insulin, percent body fat, smoking, alcohol use, and physical activity within each sex. Multiple linear regression and analysis of covariance were used to estimate the independent determinants of plasma leptin concentration separately among men and women. RESULTS: Stepwise linear regression analyses revealed statistically significant associations of leptin with percent body fat, fasting insulin, cigarette smoking, and physical activity (both inversely) among men (p < 0.05 for each). Among women, percent body fat, fasting insulin (both positively), cigarette smoking, and alcohol use (inversely) were independent predictors of leptin levels explaining over 70% of the variance. Analyses of covariance revealed that women had higher adjusted mean leptin levels than men (13.1 ng/ml vs. 5.9 ng/ml; p < 0.001), whereas no separate effect of ethnicity was noted. CONCLUSIONS: Although adiposity was the strongest correlate of leptin levels, fasting insulin and several health habits and behaviors were independently associated with leptin. After adjustment for these factors, women had significantly higher mean leptin levels than men. The independent association among leptin and insulin levels is intriguing and suggests additional avenues for epidemiologic research.

The relation of fasting insulin to blood pressure in a multiethnic population: the Miami Community Health Study.

PURPOSE: The aim of this study was to examine the associations among fasting insulin, adiposity, waist girth, and blood pressure among a nondiabetic multiethnic population. METHODS: A cross-sectional study was performed among 25-44-year-old African-Americans (n = 159), Cuban-Americans (n = 128), and non-Hispanic whites (n = 207) selected from Dade County, Florida. Fasting insulin levels were correlated with resting blood pressure level within each ethnic group. The separate effects of percentage body fat and waist girth on the association between blood pressure and insulin were analyzed in multiple linear regression and analysis of covariance. RESULTS: Fasting insulin was positively associated with systolic (r = 0.26-0.39; P < 0.01) and diastolic blood pressure (r = 0.19-0.30; P = 0.10 to P < 0.001) among women of all ethnic groups and among non-Hispanic white men (r = 0.27; P < 0.05). Stepwise linear regression analyses revealed statistically significant associations between systolic and diastolic blood pressure and fasting insulin level in non-Hispanic whites independent of other covariates, including sex and percentage body fat (P < 0.001). Fasting insulin was also independently and significantly related to systolic blood pressure among African-Americans (P = 0.02). Among Cuban-Americans, sex and percentage body fat were the main correlates of blood pressure level. Analysis of covariance revealed a relationship between insulin and blood pressure that was independent of waist girth among men and women. CONCLUSIONS: Fasting insulin level and blood pressure were positively associated among African-Americans and non-Hispanic whites. This association was not entirely due to the common association with percentage body fat or waist girth.

Does insulin resistance unite the separate components of the insulin resistance syndrome? Evidence from the Miami Community Health Study.

A number of coronary heart disease risk factors have been identified that often cluster together to increase the risk of macrovascular disease. This cluster is referred to as the insulin resistance syndrome, and the risk factors commonly include dyslipidemia, elevated blood pressure, an android pattern of body fat distribution, and glucose intolerance. Whether hyperinsulinemia or insulin resistance per se provides a common pathway for these metabolic abnormalities is unclear. The authors studied 50 nondiabetic persons who had completed a euglycemic hyperinsulinemic clamp protocol in addition to a 75-g oral glucose tolerance test and other measures of the coronary risk profile. Using principal-component analysis, we reduced nine coronary risk factors to two uncorrelated factors that explained 54.5% of the variance. Factor 1 consisted of positive loadings for uric acid, systolic and diastolic blood pressure, triglyceride concentration, and waist girth and negative loadings for HDL cholesterol and the rate of insulin-mediated glucose disposal (M, in milligrams per kilogram of body weight per minute). M also loaded on factor 2, along with fasting insulin and glucose concentrations, diastolic blood pressure, and waist girth. The observation that M loaded on both factors suggests that a resistance to insulin action may provide the mechanism uniting the features of the insulin resistance syndrome. Hyperinsulinemia with concomitant insulin resistance may be necessary to produce this metabolic derangement, as well as the increased risk of macrovascular complications.

Insulin response in a triethnic population: effects of sex, ethnic origin, and body fat. Miami Community Health Study.

OBJECTIVE: To assess sex and ethnic differences in hyperinsulinemia/insulin resistance and to examine the impact of percent body fat on such differences. RESEARCH DESIGN AND METHODS: A cross-sectional epidemiological study was performed in a normoglycemic population of African-Americans (n = 159), Cuban Americans (n = 128), and non-Hispanic whites (n = 207) who resided in Dade County, Florida, from 1990 to 1995. The insulin area under the curve (AUC) in response to a standard 75-g oral glucose tolerance test (OGTT) was used as an indicator of hyperinsulinemia/insulin resistance. Analysis of covariance was performed to compare sex and ethnic differences in the insulin AUC. Multiple linear regression was used to evaluate the independent correlates of the insulin AUC. RESULTS: After covariate adjustment for percent body fat, men displayed a significantly higher insulin AUC than did women (P < 0.001). African-Americans and Cuban-Americans each had a significantly higher insulin AUC than did non-Hispanic white participants (P = 0.01). Alcohol consumption was inversely related to AUC (P = 0.04). CONCLUSIONS: Despite the greater percentage of body fat in women, the insulin AUC was similar in women and men. After adjustment for the sex difference in percent body fat, women displayed a lower insulin AUC than did men, indicating enhanced insulin sensitivity. These differences by sex and ethnicity in insulin resistance are consistent with established differences in heart-disease risk (i.e., higher in men and African-Americans) and suggest that hyperinsulinemia/insulin resistance may partly underlie such differences.

Internal tremor in patients with Parkinson's disease.

Although sensory symptoms were not originally described in Parkinson's disease (PD), in recent years it has been increasingly recognized that painful sensations and paresthesias occur in approximately 40% of patients. It has been our observation that PD patients often describe a sensation of internal tremor, a feeling of tremor inside the chest, abdomen, arms, or legs that cannot be seen. We investigated the prevalence and characteristics of internal tremor by administering a questionnaire to 100 consecutive patients with PD and 50 age-matched controls seen in our movement disorders center. A sensation of internal tremor was present in 44% of this sample of PD patients and in 6% of the control population (p < 0.0001). The presence of internal tremor was unrelated to Unified Parkinson's Disease Rating Scale score, Hoehn and Yahr stage, duration of disease, or the presence of observable tremor. The frequency of other sensory symptoms (aching, tingling, burning) was higher in the PD patients with internal tremor (73%) than in those without (45%; p = 0.005). Internal tremor is associated with anxiety in 64% of patients (p < 0.0001). It was described as uncomfortable and was unrelieved by antiparkinsonian medication in three quarters of patients. A sensation of internal tremor is commonly reported by PD patients and should be recognized as a useful diagnostic factor in PD.

The female 'insulin advantage' in a biracial cohort: results from the Miami Community Health Study.

OBJECTIVE: To determine the extent to which gender differences in the rate of insulin-mediated glucose disposal are influenced by differences in body fatness. DESIGN: A cross-sectional study of a biracial sample of men and women drawn from a population-based study. SUBJECTS: Twenty-five 25-44 year old residents of Dade County, FL. Twenty-five African-Americans (14 men and 11 women) and 28 white, nonHispanics (15 men and 13 women). All participants were free of diabetes mellitus (WHO Criteria). MEASUREMENTS: All persons volunteered to undergo a hyperinsulinemic euglycemic clamp procedure to determine the rate of insulin-mediated glucose disposal (insulin sensitivity, M). Several measures of body fatness were quantified and the percentage body fat determined according to published equations. RESULTS: Men and women had similar unadjusted M values. Within each gender and ethnic group M was inversely related to percentage body fat (r = -0.55 to -0.84; p < 0.05). After adjustment for percentage body fat, women were more insulin sensitive than men (10.1 vs 5.1 mg/kg/min among African-Americans and 10.1 vs 6.9 mg/kg/min among white, nonHispanics; p < 0.05 for each). When M was expressed per unit of fat free mass, women were still significantly more insulin sensitive than men (p < 0.05 for each ethnic group). In multivariate analyses, gender and percentage body fat were independently related to M in both ethnic groups accounting for 70% of the variance among African-American participants and 34% of the variance among white nonHispanic participants. CONCLUSION: The similar M values between men and women despite the higher percent body fat among women indicate that women are more insulin sensitive in muscle tissue than men. This was substantiated when M was normalized for fat free mass. This 'insulin advantage' may be related to the lower risk of coronary disease experienced by women and the loss of this advantage may in part underlie the stronger deleterious effects of diabetes that women suffer.

South Florida Program on Aging and Health. Assessing the prevalence of Alzheimer's disease in three ethnic groups.

The South Florida Program on Aging and Health was initiated in 1992 with the aim to assess physical and mental health of the elderly in Dade County and provide a basis for public health policy. This report describes the methodology applied in the study and preliminary screening results in a probability sample of 2,400 African American, Cuban American and white non-Hispanic American elderly men and women. Of 2,013 participants screened by May 1995, 11.5% had cognitive impairment. An increase in prevalence from 4-7% to 25-36% with advancing age was found among men and women of each group, from the youngest (65-74) to the oldest (85+ years). Male and female prevalences were similar but vary by ethnic group and age.

On the sample size for one-sided equivalence of sensitivities based upon McNemar's test.

In this paper we formalize the problem of testing the one-sided equivalence in the sensitivities of two medical diagnostic tests under a matched-pair study design. We derive conditional and unconditional sample size formulae which are decreasing functions of the probability of being diagnosed by both tests. We calculate upper boundary and midpoint sample sizes. Results of a Monte Carlo simulation study that compares the proposed sample size formulae with that of Lachenbruch suggest that our midpoint conditional sample size is the best choice to obtain the desired power for the type of equivalence studies discussed in the paper.

Assessment of the Vital Signs Quality of Life Questionnaire in three studies on hypertension.

The Vital Signs Quality of Life Questionnaire is a patient survey developed to assess the effects of treatment on 25 variables associated with a sense of well-being and perceptions of general health, mental functioning and social performance. Data collected from this questionnaire in three studies on hypertension were analysed and are presented here. In study 1, low-dose verapamil significantly reduced office and ambulatory diastolic (DBP) and systolic (SBP) blood pressure (P < 0.01) in patients with mild hypertension. In study 2, verapamil and nifedipine significantly and similarly reduced office DBP and SBP in patients with mild to moderate hypertension. In study 3, significantly greater reductions in ambulatory DBP and SBP were observed with verapamil compared with placebo (P < 0.01) in elderly patients with mild to moderate hypertension. Reported adverse experiences were not different from those known to be associated with the study drugs. There was significant improvement in the intensity of quality of life (QOL) variables (P = 0.03) and in the total (sum of frequency and intensity) QOL score (P = 0.02) following treatment in study 1. In study 2, there were no significant changes in QOL scores following treatment with either verapamil or nifedipine. In study 3, QOL scores remained statistically unchanged for both treatment groups; however, there was a trend toward improvement with verapamil and worsening with pacebo. Taken together, the data show no negative effects of verapamil on QOL, even though verapamil demonstrated significant anti-hypertensive effectiveness. The questionnaire displayed a high level reliability, as measured by Cronbach's alpha (0.91 for both frequency and intensity).