Biomedical subjects

D Carmelli

Publications and source records attributed to D Carmelli.

At least 73 records · Page 4Linked to original sources

PubMed1992

Genetic influence on smoking--a study of male twins.

BACKGROUND: The results of twin and family studies suggest that heredity has a small influence on smoking behavior. METHODS: We conducted a genetic analysis of several aspects of smoking behavior among subjects in the National Academy of Sciences-National Research Council Twin Registry. The registry includes male twins who were born in the United States between 1917 and 1927 and who were members of the armed services during World War II. Information on smoking history was available for 4775 pairs of twins, who were first surveyed in 1967 through 1969, when they were 40 to 50 years old, and then re-surveyed in 1983 through 1985, when they were 56 to 66. Eighty percent of the subjects in this cohort had smoked at some time in their lives, 60 percent were smokers in 1967 through 1969, and 39 percent were smoking in 1983 through 1985. Similarities between twins in smoking habits at base line and at the second follow-up 16 years later were examined. The comparison of concordance for smoking between monozygotic and dizygotic twins was used to assess the relative contribution of familial and genetic factors. RESULTS: In 1967-1969 survey the ratio of observed to expected concordance for smoking was higher among the monozygotic twins than among the dizygotic twins for those who had never smoked (overall rate ratio, 1.38; 95 percent confidence interval, 1.25 to 1.54), for former smokers (overall rate ratio, 1.59; 95 percent confidence interval, 1.35 to 1.85), for current cigarette smokers (overall rate ratio, 1.18; 95 percent confidence interval, 1.11 to 1.26), and for current cigar or pipe smokers (overall rate ratio, 1.60; 95 percent confidence interval, 1.22 to 2.06). The data also suggest genetic influences on quitting smoking. Monozygotic twins were more likely than dizygotic twins to be concordant for quitting smoking (overall rate ratio, 1.24; 95 percent confidence interval, 1.06 to 1.45). CONCLUSIONS: In this cohort of adult male twins, there were moderate genetic influences on lifetime smoking practices.

Aged↗

PubMed1992

Decline in cognitive performance in aging twins. Heritability and biobehavioral predictors from the National Heart, Lung, and Blood Institute Twin Study.

The present study examined the contribution of genetic factors to Digit Symbol performance and its decline in 23 monozygotic twin pairs (mean age at examination 1, 57.1 years) and 21 dizygotic twin pairs (mean age at examination 1, 56.3 years). These men were assessed twice during a 5-year interval as part of the National Heart, Lung, and Blood Institute Twin Study. The prevalence of decline (a change, greater than 1 SD) during the 5-year interval was 35% and 39% for monozygotic and dizygotic twins, respectively. The pairwise concordance for decline was 45% in monozygotic and 8% in dizygotic twin pairs, suggesting a possible role for genetic factors in the decline in Digit Symbol performance in this sample. A comparison of baseline biologic and behavioral characteristics within monozygotic twin pairs discordant for decline in Digit Symbol performance revealed that decliners had higher initial systolic blood pressures, lower serum cholesterol levels, and lower heart rates than nondecliners.

Aged↗

PubMed1992

Age-related changes in behavioral components in relation to changes in global Type A behavior.

The current study is one of a series of studies undertaken to investigate long-term changes of the Type A behavior pattern (TABP) in surviving subjects of the Western Collaborative Group Study. Behavioral components were scored for 565 Structured Interviews (SI) of returning subjects using a recently developed methodology. Scores were compared with component ratings from the 1960-1961 intake interviews to isolate specific elements of change and evaluate their magnitude in relation to changes in global TABP. Test-retest correlations for seven behavioral components of the SI support the notion of moderate stability ranging in value from .29 to .55. Significant mean changes in component scores were observed for Type A Content, Exactingness, Competitiveness, and Hostility. Changes in Competitiveness and Hostility were Type A dependent, showing reliable increases in Type A subjects but not in Type B subjects. The observed changes in Hostility, Competitiveness, and Exactingness support the overall change in the Type A direction observed in previous analyses of these data.

Adult↗

PubMed1992

The Rationality/Emotional Defensiveness Scale--II. Convergent and discriminant correlational analysis in males and females with and without cancer.

The psychological correlates of the Rationality/Emotional Defensiveness Scale and its two subscales were examined in 1236 males and 863 females from the Western Collaborative Group Study. An additional 157 males and 164 females with some form of cancer other than of the skin were also included in this analysis. Characteristics measured included self-reported emotional control, anger expression, trait personality, depressive and neurotic symptomatology, Type A behavior, hostility, and social desirability. Results indicate that the Rationality/Emotional Defensiveness Scale is most strongly related to the suppression and control of emotions, especially anger. Scores on this scale also tend to be associated with less Type A behavior and hostility and with more social conformity. Analysis of the component subscale suggests that Antiemotionality, i.e. the extent to which an individual uses reason and logic to avoid interpersonally related emotions, is most strongly marked by the control of anger, while Rationality, i.e. the extent to which an individual uses reason and logic as a general approach to coping with the environment, is related to the control of anxiety and a higher level of trait curiosity. The psychological interpretation of the scale appears to be largely invariant across gender, unaffected by residualization of the total scale score for its association with Social Desirability, and, except for a few minor instances, unrelated to the diagnosis of cancer.

Aged↗

PubMed1992

Evidence for independent genetic influences on obesity in middle age.

The National Heart, Lung, and Blood Institute (NHLBI) Twin Study provided longitudinal data on a cohort of 514 pairs of adult male twin pairs who were examined at approximate ages of 48, 57, and 63 years. Because the sample was selected from military veterans, height and weight data were also available from their induction physical examinations when they were approximately 20 years of age. From the total NHLBI Twin Study cohort, 124 monozygotic and 119 dizygotic male twin pairs had complete data available for both members of the pair at induction and three examinations spanning 43 years of adult life. Using these data, the contributions of genetics and shared and non-shared environmental factors to BMI over the 43 year period were estimated by model fitting procedures. Model fitting included both a factor decomposition of these effects as well as a developmental path model. Results from the decomposition procedure indicate significant genetic effects at each examination cycle. Fitting a developmental path model, two independent genetic contributions to the variability of BMI were found: one at, or prior to, the induction examination about age 20, and a second between ages 20 and 48. Significant non-shared environmental contributions at each examination were also indicated, but shared environmental effects were not significant. We conclude that cumulative genetic effects explain most of the tracking in obesity over time; non-shared environmental effects, although significant at each age, are relatively short-lived and make only a minor contribution to tracking.

Adult↗

PubMed1991

Effects of selective return on estimates of heritability for body mass index in the National Heart, Lung, and Blood Institute Twin Study.

In the National Heart, Lung, and Blood Institute Twin Study, body mass index (BMI) was studied at military induction and at three subsequent examinations spanning five decades in a cohort of white, male World War II veterans. At military induction (1940s) and again at the first clinical examination of this study (1969-1973), there was close agreement of three commonly used estimates of heritability (range 0.72 to 0.80), and no evidence of a difference in total variance of BMI between the zygosities. However, at the last two examinations (1980s), the total variance in dizygotic (DZ) twins was significantly greater than that of monozygotic (MZ) twins (P less than 0.01) and these same heritability estimates varied widely. The among-pair estimate of heritability fell to unrealistic negative values, the within-pair estimate rose to values of 1.0 or greater, and the intraclass correlation coefficient estimate was slightly lower than in the entire cohort at baseline. The cause of the unequal zygosity total variance appears to have been nonparticipation at later examinations of MZ twins with extreme values of BMI, with no evidence of a similar selection process influencing DZ twins. This selection process biased the three estimates of heritability, making it difficult to determine which estimate is the most appropriate. Despite these biases, it remains clear that genetic factors contribute substantially to BMI in this population.

Adult↗

PubMed1991

Long-term changes in Type A behavior: a 27-year follow-up of the Western Collaborative Group Study.

This study examined the long-term stability of Type A behavior pattern in the Western Collaborative Group Study for 1180 surviving participants in a 27-year follow-up examination during 1986-1987. Subjects were readministered the Structured Interview (SI), originally developed for this study and first administered at intake in 1960-1961. Subjects were also given the Jenkins Activity Survey (JAS) and were asked to evaluate their behaviors currently and in the past using two short descriptions of Type A and Type B behaviors. Analyses of changes in global SI ratings, JAS score, and self-ratings showed no relationships between self-perceived changes reported in questionnaires and observed changes when assessed by the SI. Using the SI ratings, 61% of subjects retained their initial classification and 39% of subjects were rated differently, with a higher percentage of those originally typed B being rerated as A than A being rerated as B. Type B subjects rerated as A were significantly younger, retired earlier, reported better health, and were less likely to have been in a managerial or professional position than the subjects who changed from A to B.

Adult↗

PubMed1991

Effects of placentation on selected Type A behaviors in adult males in the National Heart, Lung, and Blood Institute (NHLBI) twin study.

A dermatoglyphic index derived from monozygotic (MZ) twins of known placental type was used to estimate placentation retrospectively in a sample of adult male MZ twins. Examination of behavioral test scores with respect to placentation showed that the within-pair difference of most measures of type A behavior was smaller in presumed monochorionic than presumed dichorionic pairs. Measures of cognitive function and hostility were not related to placental type. Intraclass correlations in the monochorionic subgroup of MZ twins were greater than the correlations reported for the full sample of MZ twins. The trends were strongest for the Adjective Check List scales taken at two different exams 5 years apart and, to a lesser extent, for the Framingham type A scale. Our results are most consistent with greater intrauterine environmental covariance in monochorionic MZ twins as an explanation for inflation of the MZ twin correlation relative to dizygotic (DZ) correlation reported for some type A measures.

Adult↗

PubMed1991

The NHLBI Twin Study: heritability of apolipoprotein A-I, B, and low density lipoprotein subclasses and concordance for lipoprotein(a).

Heritability of plasma apolipoprotein (apo) A-I, apo B, and low density lipoprotein (LDL) subclasses and concordance for lipoprotein(a) excess were assessed in 109 monozygotic (MZ) and 113 dizygotic (DZ) twin pairs participating in the third examination of the National Heart, Lung, and Blood Institute Twin Study. The intraclass correlation coefficient for apo A-I was significantly greater in MZ twins (0.56) than in DZ twins (0.37, P less than 0.05); however, apo A-I showed an unequal distribution in the two groups, with significantly greater total variance in DZ twins. Therefore the among-component estimate of genetic variance was applied, and the results indicated no significant heritability for apo A-I (P = 0.59). MZ and DZ twins had equal apo B variance. The intraclass correlation coefficient for apo B in MZ twins (0.71) was significantly higher than in DZ twins (0.25) (P less than 0.0001), indicating significant heritability for apo B. Plasma apo A-I levels were significantly correlated with alcohol intake (P less than 0.0001), body mass index (BMI, P less than 0.0001), and physical activity, while apo B levels were significantly correlated only with BMI (P less than 0.05). After plasma apo A-I and apo B concentrations were adjusted for all of these variables and for cigarette smoking, the analysis of variance and intraclass correlation coefficients remained virtually unchanged. The LDL type intraclass correlation coefficient was higher in MZ twins (0.58) than in DZ twins (0.32, P less than 0.005); however, greater total variance for this parameter in DZ twins was observed and after applying the among component estimate of genetic variance, no significant heritability of LDL type was observed. After adjustment for covariate effects the conclusions were not changed. Only 8.4% of MZ twin pairs, as compared with 26.7% of DZ twin pairs, were discordant for elevated lipoprotein(a) on gradient gels (P less than 0.0001). Our data indicate that there is a strong heritability for plasma apo B and lipoprotein(a), with only weak evidence for heritability of LDL type or plasma apo A-I levels within this population sample.

Aged↗

PubMed1991

The Rationality/Emotional Defensiveness Scale--I. Internal structure and stability.

In a 10-year prospective study, Grossarth-Maticek and colleagues reported that the tendency to repress and/or deny emotions was strongly predictive of cancer mortality. The method used to assess repression/denial was modified recently by Spielberger to form the Rationality/Emotional Defensiveness (R/ED) Scale. The present study investigates the psychometric properties of the R/ED Scale in 1236 male (mean age = 71.8 yr) and 863 female (mean age = 68.5 yr) participants in a 27-year follow-up of the Western Collaborative Group Study. Analyses revealed high interitem consistency (Cronbach's alpha = 0.77 and 0.78 for men and women, respectively) and two independent and stable factors that we labeled 'Anti-emotionality' (27% of total variance) and 'Rationality' (21% of total variance). Excluding cancer subjects, significant gender differences were observed for individual items, total R/ED score, and the two subscales. Comparisons of the 159 male cancer patients and the 175 female cancer patients with the corresponding noncancer subjects suggest possible gender x cancer status and age x cancer status interactions. These results challenge Grossarth-Maticek's assertion that rationality/anti-emotionality is a unidimensional construct and indicate the need to take into account the effect of age and gender on the presence of these psychological constructs.

Aged↗

PubMed1991

27-year mortality in the Western Collaborative Group Study: construction of risk groups by recursive partitioning.

The relationship of selected biological and behavioral characteristics measured at baseline examination to 27-year mortality due to coronary heart disease (CHD), cancers of all sites, and total mortality in the 3154 men that form the Western Collaborative Group Study was investigated using tree-structured survival analysis or recursive partitioning (RP). Intake (1960-61) characteristics included in the present analyses were age, serum cholesterol, systolic blood pressure (SBP), cigarette smoking, body mass index (BMI), Type A/B behavior, and behavioral hostility. Tree-structured survival analysis for CHD mortality partitioned the cohort into six groups and identified five groups with distinct survival experience. Exceptionally high CHD mortality rates (17.3 and 14.6 per thousand) were experienced by 89 older men with elevated hostility ratings and SBP less than or equal to 150, and 238 men whose initial SBP was greater than 150 mmHg. Younger men (age less than or equal to 48) with SBP less than or equal to 150 and with serum cholesterol levels greater than 227 had a death rate of 4.8 per thousand, compared with a rate of 1.7 in similar men with lower cholesterol levels. Applied to 27-year cancer mortality, the RP algorithm partitioned the cohort into four distinct survival groups. Younger (age less than 45) Type B men had superior survival compared with Type A men of similar ages, and the proportion of ever cigarette smokers in these two groups was not statistically different. The results obtained by tree-structured survival analyses were compared with results obtained by Cox regression survival analyses.

Adult↗

PubMed1991

Concordance of ischemic heart disease in the NHLBI twin study after 14-18 years of follow-up.

Morbidity and mortality were assessed in the NHLBI twin study at the end of 1987. Deaths were greater in DZ twins (58/520, 11.2%) than MZ twins (38/508, 7.5%). Ischemic heart disease concordances were 2.3 times higher in MZ pairs and 2.8 times higher in DZ pairs than expected based on the prevalence of ischemic heart disease in the cohort. Family history scores for heart disease, calculated 14-18 years earlier at entry to the study, were significantly higher in DZ pairs where one or both members later developed ischemic heart disease and in corcordant MZ pairs than in twin-pairs without any subsequent heart disease. Concordance rates were not significantly different between MZ and DZ pairs. The results agree with previous suggestions that selection at enlistment into the armed services over 40 years ago, as well as later volunteering for the NHLBI twin study, resulted in a decline in the number of concordant MZ pairs.

Cause of Death↗

PubMed1991

Involuntary retirement, Type A behavior, and current functioning in elderly men: 27-year follow-up of the Western Collaborative Group Study.

Data from 1,103 community-dwelling male participants (mean age = 71.7 years) in a 27-year cardiovascular disease follow-up were used to examine health and mental health sequelae in voluntarily and involuntarily retired Type A individuals. After controlling for age, education, and occupation, Type A subjects, determined both at intake (1960-1961) and at follow-up (1986-1987), reported significantly more frequently that retirement was involuntary. Regardless of Type A status, those reporting involuntary retirement also tended to have poorer adjustment to retirement, more illness, poorer physical status, and more depressive symptomatology. Minimal evidence was obtained on a broad array of indicators for psychological, physical, cognitive, and health status that Type As who retired involuntarily fared worse in retirement than those who retired voluntarily.

Activities of Daily Living↗

PubMed1991

Genetic effects on cardiovascular responses to cold and mental activity in late adulthood.

The purpose of the present investigation was to examine the genetic contributions to cardiovascular reactivity in an adult cohort of male twins. A total of 47 monozygotic (MZ) twin pairs and 54 dizygotic (DZ) twin pairs, aged 59 to 69 years, were laboratory tested at four sites as part of the third examination of the National Heart, Lung, and Blood Institute Twin Study. Systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded during two tasks, a mental arithmetic task involving serial subtraction and the cold pressor test. Significant cardiovascular responsivity was observed during both tasks as measured by substantial elevations in SBP, DBP, and HR from resting periods to task periods. Heritability estimates were statistically significant for SBP and DBP but not HR levels during pretask baseline periods and during both tasks. Genetic variance was maintained for blood pressure reactivity to the mental arithmetic task after adjustments for baseline and performance. No genetic variance for SBP or DBP reactivity to the cold pressor test was evident.

Aged↗

PubMed1991

Longitudinal changes in fat distribution in the Western Collaborative Group Study: a 23-year follow-up.

Anthropometric measurements for a total of 1,150 surviving subjects aged 65-86 and examined twice 23 years apart were analyzed with the following objectives: (1) to determine longitudinal changes on a large battery of anthropometric measures, (2) to examine the persistence of individual differences in the distribution of fat and relative weight, and (3) to investigate the relationship between changes in weight and changes in fat distribution. Significant changes toward an increase in size with age were observed in younger subjects below the age of 50 when first examined. In older subjects, age greater than or equal to 50, we observed a decrease in stature of 1.2 cm per decade, an overall decrease in weight of 1.6 kg, and no significant changes in trunk skinfold thickness. Longitudinal changes were most pronounced in the redistribution of fat and were also independent of weight changes. The relationships between measures of abdominal fat and overall obesity were stronger at follow-up than 23 years earlier.

Adipose Tissue↗

PubMed1990

Heritability of cognitive performance in aging twins. The National Heart, Lung, and Blood Institute Twin Study.

The genetic contribution to performance on scales designed to measure mild to moderate decrements in cognitive functioning in a population at risk is unknown. In the present analysis, 134 monozygotic and 133 dizygotic male twin pairs (mean age, 63 years) were given three cognitive tests: the Mini-Mental State examination, the Iowa Screening Battery for Mental Decline, and, for comparison, the Digit Symbol Substitution Test from the Wechsler Adult Intelligence Scale. The primary objective of the analysis was to test for a significant heritable component to performance on these measures. A secondary objective was to determine the extent to which shared variance with significant confounders such as education, age, and depression affects the outcome of the heritability analysis. Results indicate that performance on tests intended to measure cognitive decline in the elderly does have a significant genetic component and that these estimates tend to increase after adjustment for covariates. Heritability estimates adjusted for covariates were 30% for the Iowa Screening score, 60% for the Mini-Mental State score, and 67% for the Digit Symbol Substitution score.

Age Factors↗

PubMed1990

Smoking and alcohol consumption in adult male twins: genetic heritability and shared environmental influences.

This paper examines the heritability of cigarette smoking and alcohol consumption in 360 adult, male twin pair participants (176 monozygotic and 184 dizygotic pairs) in the second exam of the National Heart, Lung, and Blood Institute's Twin Study. Heritability estimates for smoking and alcohol use were calculated both before and after adjustment for shared variance between these behaviors and other characteristics, including coffee consumption, contact between twins, and two psychological traits: anger and activity. The purpose of the analysis was to determine the impact of adjustment for covariates on heritability estimates of smoking and alcohol use. Before adjustment, heritability of both smoking and alcohol use was highly significant and accounted for 52% and 60% of the variance, respectively. After adjustment for covariates, the heritability of smoking remained at 52% while that for alcohol use decreased to 43%. The fact that these estimates remained significant after adjustment for covariates leads to increased confidence about the role of genetics in both smoking and alcohol consumption.

Aged↗

PubMed1990

Heritability of substance use in the NAS-NRC Twin Registry.

This study examines the heritability of cigarette smoking, alcohol, and coffee consumption in 4,960 adult, male twin pairs (2,390 MZ and 2,570 DZ pairs) participants in an epidemiologic survey of the NAS-NRC Twin Registry conducted in the USA during 1972-73. Heritability estimates for smoking, alcohol and coffee use were calculated both before and after adjustment for shared variance between these behaviors and other demographic characteristics including socioeconomic status and an occupational adjustment score. The objective of the analysis was to determine the impact of adjustment for covariates on heritability estimates of smoking, alcohol and coffee use. Before adjustment, genetic effects in smoking, alcohol and coffee use accounted for 53%, 36%, and 45% of the variance, respectively. After adjustment, the corresponding estimates were 35%, 29%, and 36%. The fact that these estimates remained significant after adjustment for covariates leads to increased confidence about the role of genetic factors in substance use behaviors.

Alcoholic Beverages↗