Multiple chemical sensitivity syndrome: symptom prevalence and risk factors in a military population.

OBJECTIVE: To assess the prevalence of and risk factors for self-reported symptoms suggestive of multiple chemical sensitivities/idiopathic environmental intolerance (MCS/IEI) in Persian Gulf War (PGW) veterans from Iowa and a comparison group of PGW-era military personnel. METHODS: A population-based sample of Iowa military personnel was surveyed using a cross-sectional telephone interview. Study participants were randomly drawn from 1 of 4 domains: PGW active duty, PGW National Guard/Reserve, non-PGW active duty, and non-PGW National Guard/Reserve. A complex sample survey design was used selecting participants from the following substrata: age, sex, race, rank, and military branch. The criteria for MCS/IEI were developed using expert consensus and the medical literature. RESULTS: A total of 3695 study participants (76% of those eligible) completed the telephone survey. The prevalence of symptoms suggestive of MCS/IEI in all participants was 3.4%. Veterans of the PGW reported a significantly higher prevalence of symptoms suggestive of MCS/IEI than did non-PGW military personnel (5.4% vs 2.6%); greater sensitivity to organic chemicals, vehicle exhaust, cosmetics, and smog; and more lifestyle changes. The following risk factors for MCS/IEI were identified with univariate analysis: deployment to the Persian Gulf, age (>25 years), female sex, receiving a physician diagnosis of MCS, previous professional psychiatric treatment, previous psychotropic medication use, current psychiatric illness, and a low level of preparedness. Multiple logistic regression analysis identified several independent risk factors for MCS/IEI, including deployment to the Persian Gulf, age, sex, rank, branch of service, previous professional psychiatric treatment, and current mental illness. CONCLUSIONS: Self-reported symptoms suggestive of MCS/IEI are relatively frequent in a military population and are more common among PGW veterans than comparable controls. Reported chemical sensitivities and accompanying behavioral changes were also frequent. After adjusting for age, sex, and training preparedness, previous professional psychiatric treatment and previous psychotropic medication use (before deployment) showed a robust association with symptoms suggestive of MCS.

Effect of prior aspirin use on stroke severity in the trial of Org 10172 in acute stroke treatment (TOAST).

BACKGROUND AND PURPOSE: Although the efficacy of aspirin in reducing stroke incidence is clear, its role in reducing stroke severity is disputed. This study compares stroke severity between patients who did or did not take aspirin in the week before stroke and enrollment in the Trial of Org 10172 in Acute Stroke Treatment (TOAST). METHODS: Of 1275 patients randomized, 509 reported aspirin use in the week before stroke; 766 did not. Clinical stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS) and the Supplementary Motor Examination (SME) at trial entry and at 3 months. Using these scales, we compared the categorization of stroke severity (mild, moderate, and severe) and mean scores between aspirin users and nonusers. RESULTS: The difference in distribution of baseline NIHSS scores was statistically significant between aspirin users and nonusers (P=0.006), with a greater percentage of milder strokes among aspirin users. The difference in mean baseline NIHSS scores was also significantly lower in aspirin users (8.2) and nonusers (9.3) (P=0.003). The distribution of baseline SME scores and mean SME scores also showed lower stroke severity in aspirin users than in nonusers (P=0.048 and P=0.004, respectively). At 3 months, differences in stroke severity measured by the SME but not the NIHSS remained statistically significant. Seven-day and 3-month mortality did not differ significantly. CONCLUSIONS: In this study aspirin use is associated with milder clinical deficits at stroke onset. These deficits may affect prognosis and influence response to treatment. Future clinical trials should ensure that prestroke aspirin use is comparable in study groups.

Left ventricular hypertrophy in children with blood pressures in the upper quintile of the distribution. The Muscatine Study.

From echocardiography measurements of left heart dimensions, cardiac output was estimated in 264 school children whose systolic blood pressure persisted in the lowest, middle, or highest quintile of the distribution for their age and sex. Children with blood pressure in the upper quintile were taller, heavier, and more obese. Echocardiographically determined left ventricular wall mass, corrected for body size, was significantly greater in these children than those in the lower quintiles of blood pressure. These children displayed a continuum of cardiac output. Those with the highest cardiac output in the upper blood pressure quintile had the greatest left ventricular wall mass.

The cardiovascular responses to exercise in children across the blood pressure distribution. The Muscatine study.

Children with elevated systolic blood pressure have a wide range of cardiac output. To better understand the mechanisms regulating resting and exercise blood pressure, we investigated the cardiovascular responses to both dynamic and isometric exercise in 264 children who were selected from the low, middle, and upper quintile of the distribution of blood pressure of an entire school population. We sought to identify patterns of response to exercise that correlated with both resting cardiac output and resting blood pressure. During isometric exercise, systolic pressure adjusted for age and body size increased in all groups. The low group's mean pressure remained significantly lower than the high group's pressure throughout the entire exercise period. Body size adjusted group systolic and diastolic blood pressure level differences exist during dynamic exercise. The product of the systolic blood pressure times the heart rate, in the high blood pressure group, was significantly higher throughout dynamic exercise than in the other two groups. Elevated resting resistance is correlated with elevated resistance during isometric exercise and elevated diastolic blood pressure during dynamic exercise. Cardiac index had a significant negative correlation to age (r = -0.58) at all levels of blood pressure. This observation, in children, lends some support to the concept of the evolution from a hyperkinetic circulation in early childhood to a circulation with lower cardiac output and more elevated systemic vascular resistance at an older age.

Childhood predictors of future blood pressure.

Blood pressure in infants and children is much lower than that in adults. It is suspected that children whose blood pressures are greatest for their age or body size may be destined for future hypertension. However, it is apparent that some children with lower blood pressures are also destined for hypertension as adults. Children with a family history of hypertension demonstrate greater blood pressure and heart rate responses to mental challenge. These responses are enhanced when a high salt diet is consumed. Increased maximal exercise systolic blood pressure and increased left ventricular wall mass in childhood add significantly to the prediction of future high blood pressure. In addition, the acquisition of excess weight for height from childhood to young adult life adds to the prediction of future blood pressure elevations. Both children and adults who are obese have significantly higher blood pressures than those who are lean. Approximately 34% of the variability in body mass index is explained by genotype differences at a single recessive locus, 41% by genotype differences at polygenic loci, and 25% by nongenetic factors. Thus, the genetic influence of obesity may be an important factor responsible for elevated blood pressure in both children and adults.

Enhanced forearm blood flow during mental stress in children of hypertensive parents.

This study compared changes in forearm blood flow, forearm vascular resistance, blood pressure, and heart rate elicited by mental stress (mental arithmetic) in 12 adolescents with a hypertensive parent and 13 age-matched adolescents with normotensive parents. The two groups did not differ in resting forearm blood flow, forearm vascular resistance, heart rate, or blood pressure. During mental stress, children with a family history of hypertension had a significantly greater increase in forearm blood flow than did children of normotensive parents (+37.5 +/- 8.0 vs +12.8 +/- 7.5%; p less than 0.05) and a trend toward reduced forearm vascular resistance (p = 0.08). Mental stress significantly increased systolic blood pressure (p less than 0.0001), diastolic blood pressure (p less than 0.001), and heart rate (p less than 0.03) in both groups. The blood pressure and heart rate responses to stress were not significantly different between groups. There was no evidence of a prolonged response or a different pattern of recovery in children with a family history of hypertension. This study indicates that regional blood flow responses underlying similar blood pressure increases during mental stress may be different in adolescents with and without a family history of hypertension.

Left ventricular mass and exercise responses predict future blood pressure. The Muscatine Study.

Increased blood pressure and left ventricular mass are associated with increased morbidity and mortality in adults with coronary heart disease. To define the predictors of subsequent childhood blood pressure and left ventricular mass, serial echocardiograms and blood pressure responses during exercise were studied in 274 children aged 6 to 15 years, whose systolic blood pressures were in the high, middle, or low range. Persistence of rank order for left ventricular mass and blood pressure, at rest and during exercise, was maintained over a mean follow-up period of 3.4 years, with correlations ranging from 0.33 to 0.44. Subsequent systolic blood pressure was best predicted from initial resting and maximal exercise systolic blood pressures and left ventricular mass. Subsequent left ventricular mass was best predicted from initial left ventricular mass and maximal exercise diastolic blood pressure, but resting systolic blood pressure did not add to this latter prediction. Since left ventricular mass relates best to exercise blood pressure and not to resting blood pressure, left ventricular mass may provide an integrated view of the effects of blood pressure both at rest and during stress. We speculate that increased left ventricular mass in childhood may be an important predictor of subsequent hypertension and its consequences.

Accuracy of initial stroke subtype diagnosis in the TOAST study. Trial of ORG 10172 in Acute Stroke Treatment.

Rapid identification of stroke subtype is valuable for both practicing clinicians and the optimal design of clinical stroke trials. Mechanisms of ischemic injury might differ among different stroke subtypes. Certain subtypes might be clinically identified as suboptimal for future therapeutic or prophylactic stroke trials. Some subtypes might be so clinically distinct that extensive laboratory investigation is unwarranted. Investigators in the ongoing Trial of ORG 10172 in Acute Stroke Treatment are using criteria to categorize stroke etiology among enrolled patients into one of five subtypes: large-artery atherothromboembolic, cardioembolic, small-vessel thrombotic, other etiology, or undetermined etiology. As part of the study, physicians initially predict the most likely subtype of stroke based on clinical features and baseline CT. Three months after stroke, investigators use the criteria, which also incorporate results of diagnostic testing, to reclassify stroke subtype. Initial clinical impression of subtype agreed with final determination in 62% of patients, and the rate was similar for all stroke subtypes. No stroke subtype was more accurately diagnosed than others by initial assessment. No subtype was more commonly identified by diagnostic studies. Fifteen percent of patients remained without a clear etiologic subtype diagnosis at 3 months. We conclude that clinical trials in stroke should not attempt to restrict entry into trials based on presumed stroke subtype. A careful evaluation for etiology is justified in all patients presenting with stroke, regardless of presumed subtype.

Acute blood glucose level and outcome from ischemic stroke. Trial of ORG 10172 in Acute Stroke Treatment (TOAST) Investigators.

OBJECTIVE: To study the relation between acute blood glucose level and outcome from ischemic stroke. BACKGROUND: Hyperglycemia may augment acute ischemic brain injury and increase the risk of hemorrhagic transformation of the infarct. METHODS: The authors analyzed the relation between admission blood glucose level (within 24 hours from ischemic stroke onset) and clinical outcome in 1,259 patients enrolled in the Trial of ORG 10172 in Acute Stroke Treatment (TOAST)-a placebo-controlled, randomized, double-blind trial to test the efficacy of a low-molecular weight heparinoid in acute ischemic stroke. Very favorable outcome was defined as a Glasgow Outcome Scale score of 1 and a modified Barthel index of 19 or 20. Neurologic improvement at 3 months was defined as a decrease by > or =4 points on the NIH Stroke Scale compared with baseline or a final score of 0. Hemorrhagic transformation of infarct was assessed within 10 days after onset of stroke with repeat cerebral CT. Stroke subtype as lacunar or nonlacunar (atherothromboembolic, cardioembolic, and other or undetermined etiology) was classified by one investigator after completion of stroke evaluation according to study protocol. RESULTS: In all strokes combined (p = 0.03) and in nonlacunar strokes (p = 0.02), higher admission blood glucose levels were associated with worse outcome at 3 months according to multivariate logistic regression analysis adjusted for stroke severity, diabetes mellitus, and other vascular risks. In lacunar strokes, the relationship between acute blood glucose level and outcome was related to treatment. In the placebo group, higher admission blood glucose levels were associated with better outcome at 3 months. However, in the active drug group, as the glucose level increased from 50 to 150 mg/dL, the probability of a very favorable outcome decreased sharply and remained relatively unchanged as the glucose level increased further (p = 0.002, for overall effect of glucose on outcome). Acute blood glucose level was not associated with symptomatic hemorrhagic transformation of infarcts or with neurologic improvement at 3 months. CONCLUSIONS: During acute ischemic stroke hyperglycemia may worsen the clinical outcome in nonlacunar stroke, but not in lacunar stroke, and is not associated with an increased risk of hemorrhagic transformation of the infarct.

Silent cerebral infarction in patients enrolled in the TOAST Study.

To determine the frequency, location, size, and risk factors for silent cerebral infarctions (SCIs) on brain CT, we identified 629 patients without a history of previous stroke who were enrolled in a multicenter clinical trial of therapy for acute ischemic stroke. On the baseline CT, 143 patients (22.7%) had SCIs; 34.3% of the lesions were in the right hemisphere, 38.5% in the left hemisphere, and 27.3% were bilateral. The lesion size was < 1 cm in 65.7%, and the most common site was the basal ganglia (48.3%). Patients with SCI were compared with controls without SCI to determine the odds ratios (ORs) for each risk factor. On univariate analysis, race (black versus white) had an OR of 1.80 (95% confidence interval [CI], 1.14 to 2.85), male sex an OR of 1.68 (95% CI, 1.12 to 2.51), and congestive heart failure an OR of 1.88 (95% CI, 1.07 to 3.31). Significant risk factors on multivariate analysis include age (OR 1.03 per year, p = 0.0070), male sex (OR 1.78, p = 0.0094), and race (OR 2.43, p = 0.0004). After including interaction terms with age and hypertension and age, sex, and race, hypertension was also a significant risk factor.

Antithrombotic treatment of ischemic stroke among patients with occlusion or severe stenosis of the internal carotid artery: A report of the Trial of Org 10172 in Acute Stroke Treatment (TOAST).

OBJECTIVE: To examine the responses to early IV administration of an anticoagulant or placebo started within 24 hours of stroke among persons with an ipsilateral occlusion or severe stenosis of the internal carotid artery (ICA) identified by carotid duplex imaging. BACKGROUND: Patients with ischemic stroke of the cerebral hemisphere secondary to an ipsilateral occlusion or severe stenosis of the ICA generally have a poor prognosis. Early, accurate identification of these patients might permit improved treatment. METHODS: Exploratory analysis of outcomes at 7 days and 3 months was performed among patients enrolled in the Trial of Org 10172 in Acute Stroke Treatment (TOAST) who had an ischemic stroke in the cerebral hemisphere ipsilateral to an occlusion or a stenosis >50% of the ICA identified by carotid duplex imaging. RESULTS: Regardless of treatment, patients with duplex evidence of an occlusion of the ICA had more severe strokes and poorer outcomes at 7 days and 3 months than patients who had a stenosis. Favorable outcomes at 7 days were noted in 64 of 119 patients given danaparoid (53.8%) and 41 of 108 patients treated with placebo (38.0%; p = 0.023). By 3 months, favorable outcomes were noted in 82 patients given danaparoid (68.3%) and 58 patients administered placebo (53.2%; p = 0.021). CONCLUSIONS: Early identification by duplex imaging of an occlusion or severe stenosis of the ICA ipsilateral to a hemispheric ischemic stroke might improve selection of patients who could be treated with emergent anticoagulation. Further testing of this approach is needed.

Baseline NIH Stroke Scale score strongly predicts outcome after stroke: A report of the Trial of Org 10172 in Acute Stroke Treatment (TOAST).

OBJECTIVE: To compare the baseline National Institutes of Health Stroke Scale (NIHSS) score and the Trial of Org 10172 in Acute Stroke Treatment (TOAST) stroke subtype as predictors of outcomes at 7 days and 3 months after ischemic stroke. METHODS: Using data collected from 1,281 patients enrolled in a clinical trial, subtype of stroke was categorized using the TOAST classification, and neurologic impairment at baseline was quantified using the NIHSS. Outcomes were assessed at 7 days and 3 months using the Barthel Index (BI) and the Glasgow Outcome Scale (GOS). An outcome was rated as excellent if the GOS score was 1 and the BI was 19 or 20 (scale of 0 to 20). Analyses were adjusted for age, sex, race, and history of previous stroke. RESULTS: The baseline NIHSS score strongly predicted outcome, with one additional point on the NIHSS decreasing the likelihood of excellent outcomes at 7 days by 24% and at 3 months by 17%. At 3 months, excellent outcomes were noted in 46% of patients with NIHSS scores of 7 to 10 and in 23% of patients with scores of 11 to 15. After multivariate adjustment, lacunar stroke had an odds ratio of 3.1 (95% CI, 1.5 to 6.4) for an excellent outcome at 3 months. CONCLUSIONS: The NIHSS score strongly predicts the likelihood of a patient's recovery after stroke. A score of > or =16 forecasts a high probability of death or severe disability whereas a score of < or =6 forecasts a good recovery. Only the TOAST subtype of lacunar stroke predicts outcomes independent of the NIHSS score.

A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's disease.

A 1-year, double-blind, placebo-controlled, randomized, parallel-group study compared the efficacy and safety of acetyl-L-carnitine hydrochloride (ALCAR) with placebo in patients with probable Alzheimer's disease (AD). Subjects with mild to moderate probable AD, aged 50 or older, were treated with 3 g/day of ALCAR or placebo (1 g tid) for 12 months. Four hundred thirty-one patients entered the study, and 83% completed 1 year of treatment. The Alzheimer's Disease Assessment Scale cognitive component and the Clinical Dementia Rating Scale were the primary outcome measures. Overall, both ALCAR- and placebo-treated patients declined at the same rate on all primary and most secondary measures during the trial. In a subanalysis by age that compared early-onset patients (aged 65 years or younger at study entry) with late-onset patients (older than 66 at study entry), we found a trend for early-onset patients on ALCAR to decline more slowly than early-onset AD patients on placebo on both primary endpoints. In addition, early-onset patients tended to decline more rapidly than older patients in the placebo groups. Conversely, late-onset AD patients on ALCAR tended to progress more rapidly than similarly treated early-onset patients. The drug was very well tolerated during the trial. The study suggests that a subgroup of AD patients aged 65 or younger may benefit from treatment with ALCAR whereas older individuals might do more poorly. However, these preliminary findings are based on past hoc analyses. A prospective trial of ALCAR in younger patients is underway to test the hypothesis that young, rapidly progressing subjects will benefit from ALCAR treatment.

Arterial platelet accumulation in experimental hypercholesterolemia.

Accumulation of arterial platelets was calculated from 51Cr radioactivity in the intima-inner media of flushed, perfuse-fixed aortas and branch vessels of cynomolgus monkeys 48 hours after labeling of the blood platelets. In normo-cholesterolemic controls the radioactivity per square centimeter of tissue was consistently higher in aortic branching sites (circumostial aorta) than in the remainder of the aorta. In monkeys given 10 and 100 days of hypercholesterolemic diet radioactivity rose in circumostial aorta in proportion to increases in streaks and in areas of Evans blue uptake. In branch artery inner wall, where intimal changes were minimal and usually absent, counts were significantly greater in animals given 100 days of hypercholesterolemic diet than in controls. After 10 days of hypercholesterolemic diet the mean radioactivity in aortic branch artery inner wall uniformly exceeded control values, but usually nonsignificantly, permitting the speculation that changes in platelet-intima interactions may occur in widespread fashion throughout the arterial tree very early in hypercholesterolemia when lesion formation is incipient or absent.

Is there a Persian Gulf War syndrome? Evidence from a large population-based survey of veterans and nondeployed controls.

PURPOSE: Concerns have been raised about whether veterans of the Gulf War have a medical illness of uncertain etiology. We surveyed veterans to look for evidence of an illness that was unique to those deployed to the Persian Gulf and was not seen in comparable military controls. SUBJECTS AND METHODS: A population-based sample of veterans (n = 1,896 from 889 units) deployed to the Persian Gulf and other Gulf War-era controls (n = 1799 from 893 units) who did not serve in the Gulf were surveyed in 1995-1996. Seventy-six percent of eligible subjects, including 91% of located subjects, answered questions about commonly reported and potentially important symptoms. We used factor analysis, a statistical technique that can identify patterns of related responses, on a random subset of the deployed veterans to identify latent patterns of symptoms. The results from this derivation sample were compared with those obtained from a separate validation sample of deployed veterans, as well as the nondeployed controls, to determine whether the results were replicable and unique. RESULTS: One half (50%) of the deployed veterans and 14% of the nondeployed controls reported health problems that they attributed to military service during 1990-1991. Compared with the nondeployed controls, the deployed veterans had significantly greater prevalences of 123 of 137 (90%) symptoms; none was significantly lower. Factor analysis identified three replicable symptom factors (or patterns) in the deployed veterans (convergent correlations > or =0.85). However, these patterns were also highly replicable in the nondeployed controls (convergent correlations of 0.95 to 0.98). The three factors also accounted for similar proportions of the common variance among the deployed veterans (35%) and nondeployed controls (30%). CONCLUSIONS: The increased prevalence of nearly every symptom assessed from all bodily organ systems among the Gulf War veterans is difficult to explain pathophysiologically as a single condition. Identification of the same patterns of symptoms among the deployed veterans and nondeployed controls suggests that the health complaints of Gulf War veterans are similar to those of the general military population and are not consistent with the existence of a unique Gulf War syndrome.

Childhood risk factors for high adult blood pressure: the Muscatine Study.

In adult populations, elevated blood pressure is related to the development of occlusive atherosclerosis, stroke, and renal disease. The significance of blood pressure levels in childhood, unless extremely elevated, has not been related to disease outcomes. In this study, the risk of high blood pressure in young adult life is evaluated based on the observations of blood pressure and other factors made during the school-aged years. Subjects, 2445 in number, were first observed at ages 7 through 18 years and again between 20 and 30 years. During childhood, measurements of blood pressure, height, and weight were made in alternate years. At adult ages, the same measurements were again made and a health questionnaire was administered. According to the data, adult blood pressure is correlated with childhood blood pressure, body size, and change in ponderosity from childhood to adult life. Adult ponderosity is related to childhood ponderosity, and those who are most obese as adults show the greatest increase in weight for height from their childhood years. These observations suggest that strategies to prevent the acquisition of excess ponderosity during adolescence may be useful in preventing adult hypertension.

Lipoproteins in the progeny of young men with coronary artery disease: children with increased risk.

The authors studied 173 progeny from 63 families in which the father had angiographically diagnosed coronary artery disease by 50 years of age. To assess the nature of the coronary risk factors in these families, we measured their height and weight to calculate Quetelet index (wt/ht2), BP, fasting plasma cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were measured in the affected fathers, their wives, and their progeny. These values were compared with age- and sex-specific values from the Lipid Research Clinic data. Sixty-five percent of the affected fathers and 51% of the progeny had elevated triglyceride, elevated low-density lipoprotein cholesterol, diminished high-density lipoprotein cholesterol, or combinations thereof. The distribution of the lipids and lipoproteins in the children bore a close resemblance to those observed in the affected fathers. A significant number of the mothers had diminished high-density lipoprotein cholesterol, which was attributed to their obesity. Screening the progeny of young coronary artery disease patients is therefore highly productive in identifying young people at excessive risk for future coronary artery disease. Early identification of this young high-risk population offers an opportunity for early initiation of preventive measures.

Factors affecting the relationship between childhood and adult cholesterol levels: the Muscatine Study.

A group of 2,446 subjects initially examined at 8 to 18 years of age were reexamined as young adults of 20 to 25 or 26 to 30 years of age. Measurements of cholesterol, height, weight, and triceps skinfold thickness were obtained during childhood. Lipids, lipoprotein fractions, and family history, as well as medication, alcohol, and tobacco use, were determined during the adult examination. Elevated levels of cholesterol during childhood were associated with elevation in adult life. Obesity acquired in adolescence and the young adult years, oral contraceptive use, and cigarette smoking had deleterious effects on adult cholesterol levels and lipoprotein fractions.

Assessing children's blood pressure--considerations of age and body size: the Muscatine Study.

Blood pressure was assessed in 4,207 children, aged 5 to 18 years, examined in the schools of Muscatine, Iowa during 1981. Overall, 69.9% of the age-sex-specific quintiles and height-sex-specific quintiles of systolic blood pressure were identical. In only 1.0% of children did these quintiles differ by more than one. Children whose blood pressure was in the highest quintile for both age and height were more obese than their peers. Those whose blood pressure was high for age but not for height were proportionately taller and heavier than their age peers. Children whose blood pressure was high for height but not for age were older, shorter, and lighter. Thus, having precocious levels of blood pressure for age during childhood is associated with excessive body weight or precocious height, whereas having high blood pressure for height but not for age is associated with being short for age. The latter suggests that age may be a factor independent of height and weight affecting blood pressure level in childhood. These relationships of body size and age to blood pressure must be considered when evaluating children's blood pressure levels in the clinical setting, and a technique for doing so is presented.

Normal blood pressure and the evaluation of sustained blood pressure elevation in childhood: the Muscatine study.

This study describes the seated blood pressure distributions of 6,622 predominantly white schoolchildren in Muscatine, Iowa. Subjects with seated pressures equal to or greater than the 95th percentile for age and sex or 140 mm Hg systolic or 90 mm Hg diastolic were examined on repeated occasions. Approximately 13% of subjects were found to have blood pressures at these levels when first examined, but less than 1% were found to have persistent blood pressure elevations. Of 41 subjects found to have persistent blood pressure elevations, 23 were obese with relative weights in excess of 120%. Of the 18 lean subjects, 5 had secondary hypertension and 13 were considered to have essential hypertension. Mass screening of school-age children identifies many children with transient elevation of blood pressure and few with fixed high blood pressures. Children's blood pressures should be assessed during their continuing care where pressures can be measured over a period of time to identify those with fixed blood pressure elevations.