Dependence of exhaled breath composition on exogenous factors, smoking habits and exposure to air pollutants.

Non-invasive disease monitoring on the basis of volatile breath markers is a very attractive but challenging task. Several hundreds of compounds have been detected in exhaled air using modern analytical techniques (e.g. proton-transfer reaction mass spectrometry, gas chromatography-mass spectrometry) and have even been linked to various diseases. However,the biochemical background for most of compounds detected in breath samples has not been elucidated; therefore, the obtained results should be interpreted with care to avoid false correlations. The major aim of this study was to assess the effects of smoking on the composition of exhaled breath. Additionally, the potential origin of breath volatile organic compounds (VOCs) is discussed focusing on diet, environmental exposure and biological pathways based on other's studies. Profiles of VOCs detected in exhaled breath and inspired air samples of 115 subjects with addition of urine headspace derived from 50 volunteers are presented. Samples were analyzed with GC-MS after preconcentration on multibed sorption tubes in case of breath samples and solid phase micro-extraction (SPME) in the case of urine samples. Altogether 266 compounds were found in exhaled breath of at least 10% of the volunteers. From these, 162 compounds were identified by spectral library match and retention time (based on reference standards). It is shown that the composition of exhaled breath is considerably influenced by exposure to pollution and indoor-air contaminants and particularly by smoking. More than 80 organic compounds were found to be significantly related to smoking, the largest group comprising unsaturated hydrocarbons (29 dienes, 27 alkenes and 3 alkynes). On the basis of the presented results, we suggest that for the future understanding of breath data it will be necessary to carefully investigate the potential biological origin of volatiles, e.g., by means of analysis of tissues, isolated cell lines or other body fluids. In particular, VOCs linked to smoking habit or being the results of human exposure should be considered with care for clinical diagnosis since small changes in their concentration profiles(typically in the ppt(v)­ppb(v) range) revealing that the outbreak of certain disease might be hampered by already high background.

The analysis of healthy volunteers' exhaled breath by the use of solid-phase microextraction and GC-MS.

We analysed breath and inhaled room air samples from 39 healthy volunteers (28 non-smokers, 8 smokers and 3 ex-smokers) by SPME-GC-MS. Mixed expiratory and indoor air samples were collected in freshly cleaned Tedlar bags. Eighteen millilitres of each sample were transferred into sealed, evacuated glass vials, preconcentrated by solid-phase microextraction (SPME, carboxen/polydimethylsiloxane) and investigated by gas chromatography with mass spectrometric detection (GC-MS). For the unequivocal identification of potential marker compounds, pure calibration mixtures of reference compounds (depending on commercial availability) were prepared to determine the retention time and mass spectra with respect to our analytical setting. Applying the adapted SPME-GC/MS method with limit of detection in the high ppb range (0.05-15.00 ppb), we succeeded in identifying altogether 38 compounds with concentrations in exhaled breath being at least 50% higher than concentration in inhaled air. From these 38 compounds, 31 were identified not only by the spectral library match but also by retention time of standards. A comparison of retention times and spectrum obtained for standards and determined compounds was performed. We found hydrocarbons (isoprene, 2-pentene, 2-methyl-1-pentene, benzene, toluene, p-cymene, limonene, 2,4-dimethylheptane, n-butane), ketones (acetone, hydroxypropanone, methylvinyl ketone), ethers (dimethyl ether, 1,3-dioxolane), esters (ethyl acetate), aldehydes (propanal, hexanal, heptanal, acrolein) and alcohols (ethanol, 2-metoxyethanol, isopropyl alcohol, 2,2,3,3- tetramethylcyclopropanemethanol, 3,4-dimethylcyclohexanol). Proper identification of compounds in different cohorts of patients and volunteers is the base for further investigation of origin, biochemical background and distribution of potential breath biomarkers.

Alcohol consumption and mortality. I. Characteristics of drinking groups.

AIMS: This is the first of a set of three papers evaluating drinking status and mortality risk. Analyses of multiple studies describe associations of drinking patterns with characteristics hypothesized to confound the relationships between drinking status and mortality. Characteristics which both significantly differentiate drinking groups and are consistent across studies would suggest that mortality studies not controlling for them may be compromised. DESIGN AND PARTICIPANTS: Associations are evaluated from the raw data of 10 general population studies which contained mortality data. Long-term abstainers are compared to former drinkers, long-term abstainers and former drinkers are compared to light drinkers (by quantity, frequency and volume in separate analyses) and moderate to heavy drinkers are compared to light drinkers. Tetrachoric correlation coefficients assess statistical significance; meta-analysis determines if associations are homogeneous across studies. MEASUREMENTS: Measures of alcohol consumption are quantity, frequency and volume; long-term abstainers are differentiated from former drinkers. Multiple measures of health, social position, social integration and mental health characteristics are evaluated. FINDINGS: Across studies, adult male former drinkers are consistently more likely to be heavier smokers, depressed, unemployed, lower SES and to have used marijuana than long-term abstainers. Adult female former drinkers are consistently more likely to be heavier smokers, in poorer health, not religious, and unmarried than long-term abstainers. Both types of abstainers tend to be of lower SES than light drinkers and report poorer health (not consistent). Female abstainers are more likely to be of normal or overweight than light drinkers. CONCLUSIONS: Characteristics of two groups of abstainers, other than their non-use of alcohol, may confound the associations found between drinking and mortality risk.

Alcohol consumption and mortality. II. Studies of male populations.

AIMS: This is the second of a set of three papers evaluating drinking status and mortality risk. Analysis of eight general population surveys of men evaluated all-cause mortality rates by drinking pattern. DESIGN AND PARTICIPANTS: Raw data from three studies of youth and five studies of adults were evaluated. Logistic regression models controlled for confounding characteristics. Meta-analysis combined study results. MEASUREMENTS: Drinking pattern was alternatively defined by quantity, frequency and volume of drinking. Final models included drinking pattern (as well as abstinence in the youth models and long-term abstainers and former drinkers in adult models), age and other confounding variables. Models also evaluated interactions of age and, respectively, long-term abstinence and former drinking. FINDINGS: No evidence was found for the hypothesis that abstinence is associated with greater mortality risk than light drinking. In the youth samples, abstainers had a lower risk of dying than those drinking less than 15 times per month. One study of the adult samples showed a significant age by former drinker interaction; this did not alter the lack of association of former drinking with mortality risk or the homogeneity of results across studies for this finding. The most consistent finding was the association of heavy drinking with mortality among youth. Among adults, drinking 43 or more drinks per month and drinking 21 or more times per month were associated with increased mortality risk. Quantity per occasion was not significantly associated with mortality risk among adults. CONCLUSIONS: That frequent drinking was related to mortality risk, whereas heavier quantity was unrelated, is inconsistent with the belief that daily consumption of a few glasses of wine has salutary effects. Empirically, however, this pattern tends to be unusual. Findings were homogeneous across studies lending generalizability to results.

Alcohol consumption and mortality. III. Studies of female populations.

AIMS: This is the third of a set of three papers evaluating drinking status and mortality risk. Analysis of three general population surveys of women evaluated all-cause mortality rates by drinking pattern. DESIGN AND PARTICIPANTS: Raw data from three studies of adult women were evaluated. Logistic regression models controlled for confounding characteristics. Meta-analysis combined study results. MEASUREMENTS: Drinking pattern was alternatively defined by quantity, frequency and volume of drinking. Final models included drinking pattern (including long-term abstainers and former drinkers) as well as age and other confounding variables. Models also evaluated interactions of age and, respectively, long-term abstinence and former drinking. FINDINGS: In models in which age was controlled, odds of death for long-term abstainers and former drinkers (defined by volume or quantity) were greater than those for light drinkers; odds of death for moderate and heavy drinkers (defined by quantity) were greater than those for light drinkers. When other psychosocial attributes were controlled, odds of death were similar for abstainers and light drinkers. When other psychosocial attributes were controlled, odds of death for heavy drinkers (defined by volume and quantity) were greater than those for light drinkers. When interactions of age and the two forms of abstinence were introduced, one study showed a significant effect of age and former drinking. CONCLUSIONS: Results were consistent with the hypothesis that characteristics of abstainers other than their non-use of alcohol may account for their higher mortality risk. With the exception of former drinkers compared to light drinkers, when interactions were introduced into models (for measures of quantity and frequency) findings were homogeneous across studies, lending generalizability to results.

Determinants of life-course variation in the frequency of alcohol consumption: meta-analysis of studies from the collaborative alcohol-related longitudinal project.

OBJECTIVE: This report evaluates the relative contribution of predictors of change in the frequency of alcohol consumption among drinkers, based on the quantitative synthesis of data from 27 longitudinal studies of the general population. The analysis has two objectives: (1) to evaluate the impact of selected demographic characteristics on the magnitude and trajectory of change in drinking across multiple samples, and (2) to assess the influence of methodological characteristics on the consistency of results across studies. METHOD: Raw data from studies including two serial measures of the frequency of alcohol consumption are analyzed. Fixed, random and mixed effects models for meta-analysis are used to pool measures across observations and model the influence of predictors on variability between results. RESULTS: Gender-based variation in the patterning of change is present across all observations, but concentrated in early periods of the life course. Age displays significant predictive effects across all observations, but statistically uniform results are obtained for subjects aged 30 and over. The national origin of study predicts larger amounts of variation than do other demographic predictors in the models. Significant effects are observed for several methodological characteristics of studies. Variation among effect estimates is associated with differences between samples in the interval between first and final measurements, the date of first measurement (a proxy for the historical context of the sample), the percentage retention of subjects between measurements and the time frame of the original alcohol measure. CONCLUSIONS: Based on the synthesis of data from multiple longitudinal samples, this study (1) characterizes normative developmental patterning in the frequency of alcohol consumption and demonstrates the varying effects of demographic factors across the life-course: (2) indicates the key influence of cultural and historical context on the establishment of drinking patterns; and (3) confirms the impact of methodological differences on variation in the results of studies.

Aggregate-level predictors of the prevalence of selected drinking patterns in multiple studies: a research synthesis from the Collaborative Alcohol-Related Longitudinal Project.

This paper examines the prevalence of two "at-risk" alcohol drinking patterns (infrequent heavy drinking and frequent heavy drinking) within age/gender groups in multiple general population studies. When heterogeneity in findings across studies is found, we test the hypotheses that suicide, divorce, unemployment rates, and the per capita consumption of alcohol in each country are associated with the prevalence of these drinking patterns. These analyses should inform the literature on the relationships between societal factors and the prevalence of persons in different societies and periods in history that drink at these levels.

Gender differences for the risk of alcohol-related problems in multiple national contexts.

The primary research question asked is: After holding alcohol consumption constant, will men and women be at equal risk for a variety of alcohol-related problems? Since women are actually at a higher blood alcohol content at the same consumption levels, a physiological argument would suggest that women are at equal or greater risk for alcohol problems than men. However, variation in societal norms surrounding gender roles and/or societal-level stress may mediate the experience of men and women, regardless of the differences in physiology. Ten cross-sectional general population studies are used. Analyses control for individual-level variables (age, quantity, and frequency of drinking) and societal-level variables (proportion of women in the work force and female suicide rate) that might confound these relationships; cross-study homogeneity is examined.

Relationships of measures of alcohol consumption with alcohol-related problems in multiple studies: a research synthesis from the collaborative alcohol-related longitudinal project.

Two measures of alcohol consumption were used to predict groups of alcohol problems in 21 general population studies from 11 countries to determine (a) if quantity of drinking per occasion or frequency of drinking per month constituted significant "risk" for alcohol problems, having controlled for each as well as individual-level and aggregate-level variables which might confound these relationships and (b) if these associations were homogeneous across studies. A two-tiered analysis assessed these relationships within each study by modeling age, sex, quantity per occasion and frequency per month as predictors of alcohol problems. Meta-analysis combined test statistics to determine if they were homogeneous across studies. The meta-analysis was repeated, blocking for per capita consumption of alcohol (a trait of nations thought to measure drinking norms) and the female rate of suicide (a trait of nations thought to measure societal-level stress). When only individual-level variables were controlled (age and sex), both quantity and frequency were risk factors for each drinking problem. However, except in the case of the association of quantity with alcohol treatment, the magnitude of these risks were heterogeneous across studies. When blocking for the societal-level traits, each had more relevance for some, but not all, of the relationships between consumption and problems. Particularly striking was the well-documented finding that per capita consumption of alcohol significantly distinguished the relationships of frequency of drinking and health problems (while the female suicide rate did not) and the previously undocumented finding that the female suicide rate significantly distinguished the relationships of both quantity and frequency with treatment (while the per capita consumption of alcohol did not). These findings suggest that the impact of norms and the impact of societal stress in groups have different but significant consequences for the relationships of consumption to problems.

Societal-level predictors of groups' drinking patterns: a research synthesis from the Collaborative Alcohol-Related Longitudinal Project.

OBJECTIVES: Period effects of per capita consumption of alcohol and divorce rates are assessed for change in quantity and frequency among age/sex groups in multiple longitudinal studies. METHODS: Twenty-five studies of quantity and 29 studies of frequency are used. Studies are from 15 nations and cover periods of 1 to 21 years. Models predict the standardized mean difference for quantity and frequency based on period effects and group-level and methodological variables. RESULTS: When both the period effects of per capita consumption and the divorce rate are considered, the divorce rate significantly predicts change in quantity and frequency. An increase in the divorce rate is associated with a stronger decrease in frequency among younger people; men are more likely than women to decrease their frequency of drinking when divorce rates rise. CONCLUSIONS: Multiple societal-level factors should be considered critical in influencing the drinking patterns of groups. These results suggest that an increase in the divorce rate is associated with more "dry" social contexts, characterized possibly by drinking patterns of a more "volitive" nature (i.e., heavier quantity per occasion and less frequent drinking).

The effects of choice and task preference on the work performance of adults with severe disabilities.

We evaluated the effects of choice versus the assignment of tasks of varying preferences on the work engagement of adults with severe disabilities. The combined results of two experiments suggests that the relative preference for a task may be an important variable in the effectiveness of choice for some individuals.

A cross-study contextual analysis of effects from individual-level drinking and group-level drinking factors: a meta-analysis of multiple longitudinal studies from the collaborative alcohol-related longitudinal project.

In contextual (cross-level) analysis within multiple longitudinal general population studies, individual-level drinking behaviors (quantity per typical occasion, frequency of drinking per month and total volume of drinks per month) at final measurement are assessed by three models that simultaneously enter individual- and group-level measures. Two age groups (15-20 and 21-30) are independently assessed. In each model, the Time 1 individual-level drinking behavior and one of three group-level factors are entered. The group-level factors are (1) the percentage of abstainers at Time 1 for each age/sex cohort, (2) the Time 1 group mean for the drinking measure for the age/sex cohort and (3) the mean difference of the age/sex cohort's change in the drinking measure over time. All variables in the model are controlled by variations to exposure in per capita consumption of alcohol during the age/sex cohort's formative years and at Time 2. Meta-analysis assesses the homogeneity of the findings across studies. Models were proposed with the rationale that (1) understanding of individual drinking behavior can be advanced if individual-level data and group-level data are considered in the same models, and (2) integration of these two levels of analyses are, to date, rare. The rationale for using meta-analysis is that findings from the models can be assessed across social contexts with respect to their generalizability. The mean difference model, controlling for individual drinking at Time 1, is the most influential of the group-level models for the younger age group: the degree to which the group changes its drinking pattern is positively related to individual-level drinking behavior at final measurement, over and above the individual's drinking behavior at Time 1, for individual-level frequency of drinking among males (homogeneous among drinkers only). Younger females show more significant relationships for the mean difference females show more significant relationships for the mean difference model. Findings are significant for all relationships examined for the mean difference of the drinking of the group and the individual drinking among the older males and females. Measures of individual-level drinking for all measures at Time 1, controlling for the group-level effects, are significantly related to individual-level drinking at final measurement. The results are homogeneous for quantity (drinkers only) and volume among the young. Findings indicate that characterizations of the drinking for both the individual and the group to which the individual belongs predict measures of drinking practices on the individual level over time.

Grasp and pinch strength in children 5 to 12 years old.

The objective of this study was to establish normative data concerning grasp and pinch strength for use by clinicians who are treating children with hand problems. A population of 474 children ages 5 to 12 were tested using the Jamar dynamometer and the Preston pinch guage. Means and standard deviations of all measurements for all subjects were determined. Results of the study indicate that there is a steady increase in both grasp and pinch strength that coincides with the increase in chronological age and development; males are consistently stronger than females across the age range in all tests, although the differences are not striking. Hand dominance was judged not to be an important factor in predicting strength in this population.

Creative aging.

The terms "creative" and "aging" are antithetical according to dictionary usage-"create" being explicitly described as an active process and "aging" implicitly defined as a passive reactive one. This paper first briefly explores some divergent attitudes toward aging-negative as well as positive. A neurophysiological framework is then presented to support the belief that aging is an active and creative process. Physical, psychological and sociological aspects are explored in the context of neurophysiological data as it relates to the subject of aging. Finally, three factors which emerge from the discussion as essential to assuring a creative aging process are identified and examined.

Effects of the human dissection experience on subsequent related course work.

This pilot study was conducted to determine whether or not it is necessary for an occupational therapy (OT) student to dissect a human cadaver in order to gain the knowledge of human anatomy required for subsequent course work in neuroanatomy, kinesiology, and occupational therapy theory and practice in physical dysfunction. Junior students were permitted to select either an anatomy course in which they dissected human cadavers or one in which prosected models were used. Similarity of the academic ability of students in each of the two groups was assured by comparing cumulative grade point averages at the end of the sophomore year. Final grades in neuroanatomy, kinesiology, and the OT course were used as criteria for comparing the effects of the two anatomy course formats. Results indicate that when students are permitted to select the anatomy class of their choice, there is no significant difference in grades in subsequent related course work.