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Biomedical subjects

S T Weiss

Publications and source records attributed to S T Weiss.

At least 109 records · Page 6Linked to original sources
PubMed1998

Parental history and the risk for childhood asthma. Does mother confer more risk than father?

Although heredity plays a major role in asthma and in other allergic diseases, mechanisms underlying the inheritance of these disorders are poorly understood, as is the relative contribution of maternal and paternal conditions to risk of disease. We investigated doctor-diagnosed maternal and paternal asthma, eczema, and hay fever as cross-sectional predictors of childhood asthma and allergic disease in 306 children with a median age of 3.5 yr from families in which at least one parent had a history of either asthma or other allergic conditions. For both childhood asthma and eczema, the strongest parental predictors were the same conditions in the parents. For asthma in particular, maternal asthma was most strongly associated with asthma in the child over all ages in both univariate (OR = 3.2, 95% CI = 1.5 to 6.7) and multivariable (OR = 4.1, 95% CI = 1.7 to 10.1) models. Paternal asthma was weakly associated with childhood asthma in the univariate model (OR = 1.4, 95% CI = 0.6 to 3.2), but this association increased in magnitude in the multivariable model (OR = 2.7, 95% CI = 1.0 to 7.2). Among the children < 5 yr of age, the risk for childhood asthma associated with maternal asthma (OR = 5.0, 95% CI = 1.7 to 14.9) was greater than the risk associated with paternal asthma (OR = 1.6, 95% CI = 0. 5 to 5.9), whereas both maternal asthma and paternal asthma were associated with similar risks among children >= 5 yr of age (OR = 4. 6, 95% CI = 1.1 to 19.0 and OR = 4.1, 95% CI = 1.0 to 16.0, respectively). The odds of having a child with asthma were three times greater in families with one asthmatic parent and six times greater in families with two asthmatic parents than in families where only one parent had inhalant allergy without asthma; furthermore, inhalant allergy in one parent also conferred additional risk in the presence of asthma in the other parent. Further investigation is needed into the relative importance of genetic factors and in utero and postnatal exposures in determining the differential effects of maternal and paternal asthma on the development of childhood asthma.

Adult↗
PubMed1998

Longitudinal predictors of airway responsiveness to distilled water: the role of atopy and maternal smoke exposure.

Airway responsiveness is an objectively measurable clinical trait related to the presence of asthma. Although risk factors for this trait have been evaluated cross-sectionally, little is known about its longitudinal predictors. A population cohort of 539 children, aged 8 yrs at the start of follow-up, underwent 3-7 bronchial challenge tests spaced at 3-9 month intervals. Airway responsiveness was assessed by a single-step distilled water challenge. To investigate responsiveness as a continuous trait, the ratio of the postchallenge to prechallenge forced expiratory volume in one second was calculated. A child's repeated ratios were then regressed on the time of follow-up. The resulting child-specific regression coefficient was the outcome variable to assess longitudinal predictors of airway responsiveness (AR). Results were based on 2,267 repeated challenge tests, and indicated an overall decrease in responsiveness. Children with a diagnosis of asthma (mean+/-SD, longitudinal change in AR + yr(-1): -0.060+/-0.149), those with a positive skin-prick test (-0.018+/-0.106) and those with reported exposure to maternal smoking (-0.004+/-0.083) demonstrated increased airway responsiveness over time. All of these changes in airway responsiveness were found to be significant in multiple linear regression analysis (p<0.05). Stratified analysis further indicated that the effect of maternal smoking was observed primarily in nonatopic children and was greatest at an exposure level of > or =10 cigarettes x day(-1). In conclusion, atopy and exposure to maternal smoking can predict longitudinal change in childhood airway responsiveness.

Air Pollutants↗
PubMed1998

Impaired ventilatory function and elevated insulin levels in nondiabetic males: the Normative Aging Study.

Lower levels of baseline ventilatory function have consistently been associated with increased risk of cardiovascular mortality in prospective studies, but the underlying mechanisms are not known. Increased risk of coronary heart disease is associated with higher serum insulin levels. This report examines the relationship between ventilatory function and indirect measures of insulin resistance. Cross-sectional data from 922 nondiabetic participants in the Normative Aging Study were analysed using multiple linear regression models with adjustment for potential confounders. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were examined in relation to indicators of insulin resistance, i.e. fasting insulin and the fasting insulin resistance index (FIRI). Diabetics were excluded because impaired insulin secretion interferes with the validity of these as measures of insulin resistance. Fasting insulin and FIRI were negatively correlated with FVC and FEV1 (all p< 0.001). These associations persisted after adjusting for potential confounders including age, height, body mass index, waist to hip circumference ratio, physical activity, alcohol intake and smoking in separate multiple linear regression models, for both insulin (all p< or =0.0008) and FIRI (all p< or =0.0001). Negative cross-sectional associations between ventilatory function and indirect measures of insulin resistance were found in nondiabetic males. Insulin resistance may contribute to the previously unexplained association between ventilatory function impairment and cardiovascular mortality. Mechanisms underlying the relationship between insulin resistance and decreased ventilatory function remain to be elucidated.

Adult↗
PubMed1998

Baseline ventilatory function predicts the development of higher levels of fasting insulin and fasting insulin resistance index: the Normative Aging Study.

A consistent but as yet unexplained association between baseline ventilatory function and risk of coronary heart disease (CHD) has been reported from many prospective studies. Insulin-resistant states are associated with increased risk of CHD. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid-expiratory flow rate (MMEF) at study entry were examined as predictors for indirect measures of insulin resistance after a mean follow-up interval of 20.9 yrs in 1050 nondiabetic male subjects in the Normative Aging Study. Males in the top quintile of insulin or fasting insulin resistance index (FIRI) levels at follow-up were defined as being relatively insulin resistant. FVC was negatively associated with risk of being relatively insulin resistant using the insulin (p=0.002) or FIRI (p=0.0001) criteria at follow-up in logistic regression models adjusting for baseline age, body mass index, fat distribution pattern and cigarette smoking. Similar associations were found for FEV1 and MMEF. Additional adjustment for baseline postcarbohydrate challenge glucose levels made little difference to the results, suggesting that baseline glucose intolerance was not a significant source of bias. These findings are consistent with the possibility that insulin resistance may be one of the factors mediating the previously unexplained prospective association between impairment of ventilatory function and risk of mortality from coronary heart disease.

Adult↗
PubMed1997

Airways responsiveness and development and remission of chronic respiratory symptoms in adults.

BACKGROUND: Many patients with chronic obstructive lung disease show increased airways responsiveness to histamine. We investigated the hypothesis that increased airways responsiveness predicts the development and remission of chronic respiratory symptoms. METHODS: We used data from 24-year follow-up (1965-90) of 2684 participants in a cohort study in Vlagtwedde and Vlaardingen, Netherlands. Increased airways responsiveness was defined as a PC10 value (concentration of histamine for which challenge led to a 10% fall in forced expiratory volume in 1 s) of less than 8 mg/mL. Information on respiratory symptoms was collected by means of a standard questionnaire every 3 years. Logistic regression was used to control for age, area of residence, cigarette smoking status, and sex. FINDINGS: Participants with increased airways responsiveness (1281 observations) were more likely than those without increased airways responsiveness (5801 observations) to develop the following symptoms during any 3-year follow-up interval: chronic cough (odds ratio 1.9 [95% CI 1.2-2.9]), chronic phlegm (2.0 [1.3-3.0]), dyspnoea (2.3 [1.5-3.5]), asthmatic attacks (3.7 [2.2-6.1]), and persistent wheeze (2.7 [1.7-4.4]). The estimate of the odds ratio for the development of any of the six symptoms was 1.7 (1.2-2.3). Participants with increased airways responsiveness were less likely than those without this characteristic to show remission of these respiratory symptoms. The estimate of the odds ratio for the remission of any of the six symptoms was 0.42 (0.28-0.61). INTERPRETATION: These prospective analyses show that increased airways responsiveness is positively associated with the development of chronic respiratory symptoms and negatively associated with the remission of these symptoms in adults.

Adult↗
PubMed1997

Alcohol intake and insulin levels. The Normative Aging Study.

Much remains to be clarified in the apparently protective effect of moderate alcohol use against coronary heart disease risk. Insulin levels are positively associated with coronary heart disease risk, so recent reports of decreased insulin sensitivity among nondrinkers and lower fasting insulin levels with increasing alcohol intake suggest the possibility that insulin may play a role. Between 1987 and 1991, the authors examined fasting insulin concentrations and the empiric fasting insulin resistance index in relation to reported alcohol intake (mean, 15.3 g/day; standard deviation, 19.6; range, 0-120.6) and potential confounders. The latter included age, obesity, fat distribution, smoking, energy, saturated fat intake, antihypertensive medication, and physical activity. Participants in this cross-sectional analysis were 938 nondiabetic men from the Boston, Massachusetts, area who were part of the Normative Aging Study. Unadjusted fasting insulin levels were significantly different (p = 0.008) between categories of alcohol intake, as were fasting insulin resistance index values (p = 0.01). After adjustment for potential confounders, analysis revealed that subjects consuming moderate amounts of alcohol had the lowest fasting insulin and fasting insulin resistance index values. Compared with values from moderate drinkers, fasting insulin resistance index values were higher in those subjects reporting no alcohol intake (p = 0.011), low intake (p = 0.004), and high intake (p = 0.04). A similar pattern was observed for fasting insulin values. Among this sample of nondiabetic men, moderate drinkers had the lowest levels of fasting insulin resistance index and fasting insulin, consistent with lower levels of insulin resistance and thus lower risk for coronary heart disease. These findings suggest the possibility that the coronary heart disease-protective effects of moderate alcohol use are at least partially mediated by insulin.

Adult↗
PubMed1997

Inhaled steroids and the risk of hospitalization for asthma.

OBJECTIVE: To determine if anti-inflammatory treatment for asthma reduces the risk of asthma hospitalization. DESIGN: Retrospective cohort study. SETTING: A health maintenance organization (HMO) in eastern Massachusetts. PARTICIPANTS: Members of the HMO who were identified during the period October 1991 through September 1994 as having a diagnosis of asthma using a computerized medical record system. MAIN OUTCOME: Hospitalization for asthma. RESULTS: Of the 16941 eligible persons, 742 (4.4%) were hospitalized for asthma. The overall relative risk (RR) of hospitalization among those who received inhaled steroids was 0.5 (95% confidence interval [CI], 0.4-0.6) after adjustment for beta-agonist dispensing. Additional adjustment for age, race, other asthma medications, and amount and type of ambulatory care for asthma did not substantially affect the inverse relationship between use of inhaled steroids and hospitalization. Cromolyn was similarly associated with reduced risk, especially among children (RR,0.8; 95% CI, 0.7-0.9). In contrast, increasing beta-agonist use was associated with increasing hospitalization risk even after adjustment for other factors and medications. The steroid-associated protection was most marked among individuals who received the largest amount of beta-agonist. CONCLUSIONS: Inhaled steroids and, to a lesser extent, cromolyn confer significant protection against exacerbations of asthma leading to hospitalization. These results support the use of inhaled steroids by individuals who require more than occasional beta-agonist use to control asthma symptoms.

Administration, Inhalation↗
PubMed1997

Is worrying bad for your heart? A prospective study of worry and coronary heart disease in the Normative Aging Study.

BACKGROUND: Worry is an important component of anxiety, which recent work suggests is related to increased incidence of coronary heart disease (CHD). Chronic worry has also been associated with decreased heart rate variability. We hypothesized that high levels of worry may increase CHD risk. METHOD AND RESULTS: We examined prospectively the relationship of worry with CHD incidence in the Normative Aging Study, an ongoing cohort of older men. In 1975, 1759 men free of diagnosed CHD completed a Worries Scale, indicating the extent to which they worried about each of five worry domains: social conditions, health, financial, self-definition, and aging. During 20 years of follow-up, 323 cases of incident CHD occurred: 113 cases of nonfatal myocardial infarction (MI); 86 cases of fatal CHD; and 124 cases of angina pectoris. Worry about social conditions was the domain most strongly associated with incident CHD. Compared with men reporting the lowest levels of social conditions worry, men reporting the highest levels had multivariate adjusted relative risks of 2.41 (95% CI, 1.40 to 4.13) for nonfatal MI and 1.48 (95% CI, 0.99 to 2.20) for total CHD (nonfatal MI and fatal CHD). A dose-response relation was found between level of worry and both nonfatal MI (P for trend, .002) and total CHD (P for trend, .04). CONCLUSIONS: These results suggest that high levels of worry in specific domains may increase the risk of CHD in older men.

Adult↗
PubMed1997

Handgrip strength and insulin levels: cross-sectional and prospective associations in the Normative Aging Study.

Hyperinsulinemia is associated with insulin resistance and with the development of diabetes, hypertension, and coronary heart disease. Physical activity appears to be negatively associated with insulin resistance, although the mechanism is unclear. The relationship between physical activity and insulin resistance could be mediated, in part, by direct effects on skeletal muscle, a significant site for insulin-mediated glucose disposal. This report examines the relationship between skeletal muscle strength (as measured by handgrip dynamometry) and fasting insulin levels in a cohort of men in the ongoing Normative Aging Study (NAS). Handgrip strength was negatively associated (P = .013) with logarithmic (log) fasting insulin in cross-sectional data from 655 subjects after adjustment for potential confounders including age, body mass index (BMI), ratio of abdominal girth to hip breadth (AG/HB), usual physical activity level, and alcohol intake in a multiple regression model. In data collected prospectively among 1,195 subjects, handgrip strength measured at study entry was negatively predictive of log fasting insulin (P = .017) measured 22.9 +/- 2.6 years later, after adjustment for age, BMI, and AG/HB at study entry in a multiple linear regression model. A cross-sectional association was confirmed in an analysis of prospective data on the relationship between handgrip strength and fasting insulin levels. The findings suggest that skeletal muscle weakness may precede and predict the development of insulin resistance, and raise the intriguing possibility of some common cause in skeletal muscle pathophysiology.

Adult↗
PubMed1997

Environmental and occupational determinants of blood pressure in rural communities in China.

PURPOSE: To identify and characterize major environmental and occupational determinants of blood pressure in rural communities in China. METHODS: In 1993 we conducted a large cross-sectional, community-based study of 20,216 residents aged 15 years or older, from the Yijing area of Anhui Province (8022 men, 12,194 women), one of whom were receiving treatment for hypertension. The mean systolic blood pressure was 116.7 +/- 19.5 mmHg for men and 113.2 +/- 19.4 mmHg for women. RESULTS: The mean diastolic blood pressure was 72.4 +/- 12.1 mmHg for men and 70.4 +/- 11.6 mmHg for women. Age and body mass index were the two most important determinants of blood pressure in this population. With controls for age and body mass index, height and weight remained significant predictors of blood pressure. Multiple linear regression analysis indicated that alcohol consumption, self-reported exposure to noise, drinking of tap water and pond water, occupational exposure to dust/fumes/gases, rice consumption, inferior housing, household crowdedness, and being unmarried were related to increased blood pressure levels. Vegetable intake, frequent consumption of meat at meals, high level of physical activity, exposure to straw-combustion smoke, and pesticide use were negatively associated with blood pressure. CONCLUSIONS: Our study demonstrated that a broad array of demographic, ergonomic, nutritional, and environmental factors are critical determinants of blood pressure in this rural Chinese population.

Adolescent↗
PubMed1997

Volume history effects and airway responsiveness in middle-aged and older men. The Normative Aging Study.

In persons with asthma, a deep inhalation (DI) to total lung capacity may lead to bronchoconstriction. The intensity of this effect has been shown to correlate positively with the severity of inflammatory airflow obstruction and the level of methacholine airway responsiveness. The correlates of lung volume history effects in the general population, however, are unknown. We analyzed combined maximal and partial expiratory flow-volume data, pre- and postbronchodilator spirometry data, and methacholine challenge data from 89 middle-aged and older men participating in the Normative Aging Study. The ratio of maximal to partial expiratory flow rates (VM/VP) was significantly correlated with methacholine airway responsiveness, even after adjustment for age and baseline FEV1. The direction of this correlation indicated that men with higher VM/VP ratios (i.e., greater dilator effect of a DI) tended to have greater methacholine airway responsiveness. Subjects with a higher VM/VP ratio also tended to have a greater response to a bronchodilator. These results suggest that, in the general population, airway responsiveness relates in part to airway smooth muscle tone. The correlations suggest that this relatively simple maneuver might play a role in future epidemiologic studies.

Aged↗
PubMed1997

Sensitization to cat allergen is associated with asthma in older men and predicts new-onset airway hyperresponsiveness. The Normative Aging Study.

To explore the relationship between sensitization to inhalant allergens and adult asthma, we performed two nested case-control studies of men being followed in the VA Normative Aging Study. In Study A, 46 subjects (mean age, 61.2 +/- 8.1 yr) with symptoms of asthma and an abnormal methacholine challenge test (cases) were compared with 92 age- and smoking-history-matched subjects, who denied symptoms and had normal methacholine challenge tests (controls). The age of onset of wheezing symptoms for the cases was 49.0 +/- 15.7 yr. Serum IgE reactivity to the aeroallergens Der P 1 and 2, cat, ragweed, and mouse was compared in cases and controls. Cases were more likely to be sensitized to cat allergen (23.9% versus 4.4%, p < 0.001) than were controls. Prevalences of sensitization to Der p 1, Der p 2, ragweed, and mouse were low and similar in the two groups. In Study B, 33 cases who developed new onset airway hyperresponsiveness on methacholine challenge testing were compared with 66 age-matched controls who maintained normal methacholine challenge tests. Cases had a higher prevalence of serum IgE reactivity to cat allergen (18.2% versus 6.1%, p = 0.059) and Der p 2 (21.2% versus 10.6%, p = 0.153) measured in serum obtained 3 yr before the development of airway hyperresponsiveness. These results suggest that in older men, sensitization to cat allergen is associated with asthma and that sensitization predates airway hyperresponsiveness to methacholine.

Aged↗
PubMed1997

Annual variability in methacholine responsiveness in nonasthmatic working adults.

Change in airway responsiveness is used frequently as a clinical as well as an epidemiological tool. Changes in airway responsiveness can be superior to other measures of lung function in that they are more sensitive indicators of an environmental effect. However, normal variation in test results must be defined before change can be interpreted. To characterize annual variability in airways responsiveness, we administered a high-dose methacholine challenge at 1 yr intervals for up to 4 yrs to 105 healthy, nonasthmatic working subjects. Using this high-dose protocol, the majority of tests (83%) produced at least a 20 % fall in forced expiratory volume in one second (FEV1), allowing standard calculation of the provocative dose of methacholine causing a 20% fall in FEV1 (PD20). An annual change in methacholine responsiveness by one or more doubling doses was seen in at least 30% of subjects each year. The components of variance of airways responsiveness measures were estimated to allow direct comparison of within-subject and between-subject variability. The within-subject variability in PD20, was markedly greater than the comparable within-subject variability in FEV1. Level of FEV1 and age were both significant determinants of methacholine responsiveness. Comparison of two methods of expressing methacholine responsiveness (PD20 using the full challenge up to 250 mg x mL(-1) methacholine, and the dose-response slope using data up to 32 mg x mL(-1) methacholine as the maximum dose) had similar annual variability in censored data and mixed-effects models. We then developed an approach to statistical analysis of "right-censored" methacholine challenge data using a maximum likelihood estimation under a censored Gaussian model. These studies of methacholine responsiveness provide normative data on annual test variability in healthy, nonasthmatic working adults, and show that a shorter low-dose challenge has comparable annual variability to a lengthier high-dose challenge.

Adult↗
PubMed1997

Lack of correlation between bronchoconstrictor response and bronchodilator response in a population-based study.

Bronchodilator and bronchoconstrictor responsiveness have been considered physiological opposites in patients with obstructive airways disease. Provocation challenges have been replaced by bronchodilator tests in the assessment of cases of severe airways obstruction. The aim of this study was to examine the relationship between bronchoconstrictor and bronchodilator responsiveness, and their supposed interchangeability, in a general population. From the Vlagtwedde-Vlaardingen follow-up study, 101 adults were recruited (mean (SD) age 55 (11) yrs, 67 males and 34 females, and 31 were smokers). All completed a questionnaire on airways symptoms. Bronchoconstrictor and bronchodilator responsiveness were assessed with cumulative dose-response curves, using histamine and terbutaline, respectively. Thus, it was possible to relate histamine sensitivity of the airways (the concentration of histamine, at which forced expiratory volume in one second (FEV1) falls by 10% (PC10)) to the maximal bronchodilator response (delta FEV1) and the sensitivity to the bronchodilator (cumulative dose of inhaled terbutaline at which FEV1 increases by 10% (RD10)). Subjects with a bronchoconstrictor response (PC10 < or = 16 mg x mL(-1); n=38) had more respiratory symptoms than those without (n=63) (40 versus 21%) and also lower baseline FEV1 values (90 versus 96% predicted), but had comparable bronchodilator responsiveness. Subjects with a bronchodilator response (delta FEV1 > or = 9% of the predicted value; n=13) did not differ from those without (n=88) for all parameters, including symptoms, allergy and pulmonary function. In those with a bronchoconstrictor response, there was a weak but significant correlation between the PC10 and RD10 (rho=-0.32), but not between PC10 and delta FEV1. This study suggests that bronchoconstrictor and bronchodilator responsiveness are not highly correlated, even in subjects with airways obstruction. Symptoms were associated with the presence of a bronchoconstrictor, but not a bronchodilator, response. We conclude that bronchoconstrictor and bronchodilator responsiveness are two different phenotypic markers that are not interchangeable in epidemiological studies.

Administration, Inhalation↗
PubMed1997

Effects of obesity and fat distribution on ventilatory function: the normative aging study.

OBJECTIVE: Although the influence of obesity on ventilatory function has long been recognized, the nature of the relationship and the mechanisms are not yet clear. The purpose of this report was to examine the effects of overall obesity and fat distribution on ventilatory function. METHODS: Multiple measurements over > 30 years from 507 subjects with lifelong tobacco consumption of < or = 1 pack-year were analyzed separately in five age decades from 30 to 79 years. FVC, FEV1, ratio of FEV1 to FVC, and maximal midexpiratory flow rate (MMEF) were each adjusted for age and stature. Relative adiposity (or obesity) was assessed using the body mass index (BMI). Subscapular skinfold thickness, abdominal girth, and the ratio of abdominal girth to hip breadth (AG/HB) were used as measures of body fat distribution. Multiple linear regression was used to explore the effects of overall adiposity and body fat distribution on ventilatory function. RESULTS: BMI was positively associated with the ratio of FEV1 to FVC at all ages (p < 0.01), and negatively with FVC and MMEF between 40 and 69 years (p < 0.01). After adjustment for BMI, subscapular skinfold thickness was negatively associated with both FVC and FEV1 (p < or = 0.02) among men aged 30 to 59 years, whereas AG/HB was negatively associated with FVC and FEV1 in men aged 50 to 59 years only (p < or = 0.0004). CONCLUSIONS: Body fat distribution has independent effects on ventilatory function after adjustment for overall obesity in men. The finding that age modifies this association has implications for future research.

Adipose Tissue↗
PubMed1997

Assessment of asthma using automated and full-text medical records.

Automated medical records systems are used to study clinical outcomes and quality of care, but this requires accurate disease identification and assessment of severity. We sought to determine the reliability of identifying asthmatics through automated medical and pharmacy records, and the adequacy of such data for severity assessment. All adult health maintenance organization (HMO) members who received at least one asthma drug and an asthma diagnosis between April 1988 and September 1991 were identified. Records of a random sample were reviewed to validate the diagnosis and extract clinical information. Asthma drugs were dispensed to 15,491 individuals; 7583 (49%) also received an asthma diagnosis. Asthma drug use was three times greater for persons with diagnosed asthma compared to those with no diagnosis. Record review revealed that a coded asthma diagnosis had a positive predictive value of 86%. Nearly 4000 ambulatory encounters were reviewed, 10% of which were for asthma; the median number of encounters was two. Asthma symptoms were mentioned in 9% of all encounters; wheezing was most common. Peak flow and spirometry were measured in 4% and 1% of encounters, respectively. Records from recipients of asthma drugs who lacked an asthma diagnosis showed that 79% did not have asthma. Automated medical and pharmacy records from an HMO were relatively accurate when used to identify individuals with asthma. Similarly, most asthma drug recipients who lacked a coded diagnosis of asthma did not have asthma. However, conventional full-text records usually do not contain sufficient information to assess asthma severity, limiting the utility of such records for research and quality improvement.

Adult↗