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T Reed

Publications and source records attributed to T Reed.

At least 55 records · Page 3Linked to original sources
PubMed1995

Self-reported alcohol intake and cognition in aging twins.

OBJECTIVE: To determine the relationship between long-term alcohol intake and cognitive functioning in aging Caucasian men. METHOD: A retrospective cohort and co-twin-control study of self-reported alcohol intake and cognitive testing using the National Academy of Sciences-National Research Council (NAS-NRC) Twin Panel of U.S. veterans (born between 1917 and 1927). The study included 4,739 twins with two self-reported drinking histories (1970s and 1980s) and a telephone mental status interview (1990 and 1991) that also included 145 individuals with a diagnosis of alcoholism. RESULTS: Age and education adjusted cognitive scores were lower (p < .05) in diagnosed alcoholics than in the remainder of the subjects. To compare age and education adjusted cognitive scores in alcohol intake, the 4,739 twins were divided, based upon questionnaire data, into nondrinkers and 5 quintiles of drinkers by average reported drinks of alcohol weekly (< 1.0, 1-3.3, 3.4-8.1, 8.2-16.0, > 16.0). Past drinkers had scores lower (p < .05) than nondrinkers and all but quintiles 1 and 5 of the drinkers. The light drinkers in quintile 1 and the heavy drinkers in quintile 5 scored lower (p < .05) than the moderate drinkers in quintile 4. Monozygotic twins in quintile 4 scored higher (p < .05) than their co-twins in quintiles 1-3. CONCLUSIONS: No evidence was found to indicate an association between moderate long-term alcohol intake and lower cognitive scores in aging individuals. There was a suggestion of a small protective effect of past moderate alcohol intake on cognitive function with aging.

Aged↗
PubMed1994

Lower cognitive performance in normal older adult male twins carrying the apolipoprotein E epsilon 4 allele.

OBJECTIVE: Given the strong association of the apolipoprotein E (apoE) allele epsilon 4 with late-onset Alzheimer dementia or multi-infarct dementia, we tested whether normal older adult men with at least one epsilon 4 allele demonstrate subclinical changes in cognition and perform more poorly on tests of cognitive function compared with subjects without the epsilon 4 allele. DESIGN: Matched-pair design of normal adult male (average age, 63 years) fraternal twins. SETTING: Subjects voluntarily participated on an outpatient basis at a research or medical center facility. PARTICIPANTS: Members of the National Heart, Lung, and Blood Institute twin panel third examination previously genotyped for apoE. MAIN OUTCOME MEASURE: Education-adjusted scores on several neuropsychological tests were compared in twins discordant for the apoE epsilon 4 allele. Subjects with documented cerebrovascular disease were excluded. RESULTS: Among 20 fraternal twin pairs discordant for the presence of epsilon 4, twins with the epsilon 4 allele demonstrated poorer mean performance than their co-twins without the epsilon 4 allele. This relationship was also noted cross-sectionally where age- and education-adjusted scores of 50 individual twin subjects with at least one epsilon 4 allele demonstrated poorer performance compared with 138 individual twins without an epsilon 4 allele. CONCLUSIONS: The apoE epsilon 4 allele may be associated with decreased cognitive function in discordant twin pairs. Our results suggest that epsilon 4 may represent a potential marker for accelerated cognitive aging and such individuals may be at greater risk for development of late-onset Alzheimer dementia or multi-infarct dementia.

Alleles↗
PubMed1994

Genetic influences on age-related change in total cholesterol, low density lipoprotein-cholesterol, and triglyceride levels: longitudinal apolipoprotein E genotype effects.

This study addressed the possible influence of apolipoprotein E (apo E) genotype on age-related changes in total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), and triglyceride (TG) levels in older males. Apo E is a component of LDL, is a ligand for the LDL receptor, and apo E genotype has been consistently associated with variation in mean levels of TC and LDL-C, and also appears to influence TG levels. Using male twins followed longitudinally between mean ages of 48 and 63 years, the change in TC, LDL-C, and TG over time for individuals with the epsilon 3 epsilon 3 and the epsilon 3 epsilon 4 genotypes was contrasted. At exam 1 mean TC and LDL-C levels were lower in the epsilon 3 epsilon 3 group than in the epsilon 3 epsilon 4 group, but at exam 3 mean TC and LDL-C levels were significantly higher in the epsilon 3 epsilon 3 group than in the epsilon 3 epsilon 4 group. The rate of change in TC and LDL-C with age differed significantly between epsilon 3 epsilon 3 and epsilon 3 epsilon 4 groups. Results for TG were not statistically significantly. These findings suggest that the apo E genotype effects on risk of coronary artery disease may be age-dependent. This study demonstrates the value of longitudinal studies in refining models for genetic risk factors for disease.

Adult↗
PubMed1994

Replication of asymmetry of a-b ridge count and behavioral discordance in monozygotic twins.

We have replicated an earlier study (Rose et al., Behav. Genet. 17, 125-140, 1987) relating dermatoglyphic asymmetry to intrapair discordance in a completely new sample of monozygotic (MZ) twins. Consistent results were observed for at least 31 of 37 Minnesota Multiphasic Personality Inventory (MMPI) scales tested in the two samples. Intrapair differences were confirmed to be greater in 28 MZ pairs with asymmetric palmar a-b ridge counts than in 29 MZ pairs with little or no a-b asymmetry for at least 15 scales. We also examined longitudinal stability over a 4 to 5-year period for six MMPI scales and found suggestive evidence in three scales for greater test-retest instability in twin pairs asymmetric for a-b ridge count. The results offer new evidence for our hypothesis that an asymmetric a-b ridge count may identify individuals who are poorly buffered from developmental noise, but analyses of symmetric and asymmetric a-b ridge counts in nontwin subjects are required to extend and test the hypothesis further.

Adult↗
PubMed1994

Performance of autistic and control subjects on three cognitive perspective-taking tasks.

One explanation for the persistent social disabilities of individuals with autism is based on the nature of social stimuli, being transient, complex and very difficult to predict. It was suggested that autistic people's performance on cognitive perspective-taking tasks (a measure of understanding of other people) would be enhanced with increased predictability and reduced transience of stimulus materials. Thus autistic and control subjects were tested on Baron-Cohen, Leslie, and Frith's (1985) "Sally/Anne" task and on two other perspective-taking tasks that involved more predictable interactions and nontransient cues. Autistic subjects differed significantly from the control subjects in their ability to perform Baron-Cohen's task but not the other tasks. As well the autistic subjects performed significantly differently on the two types of tasks. Failure of the autistic subjects on the Sally/Anne task with their concurrent success on the other tasks can best be attributed to the nontransient nature of the stimuli used and the predictability of the protagonists' reactions in the two tasks on which they succeeded.

Adolescent↗
PubMed1994

16-year incidence of ischemic heart disease in the NHLBI twin study. A classification of subjects into high- and low-risk groups.

Prospective data from the National Heart, Lung, and Blood Institute (NHLBI) Twin Study were used to investigate the relationship of risk factors measured in 1970 to 1971 to 16-year incidence of ischemic heart disease (IHD) in 905 males born between 1917 and 1927. A newly developed methodology, tree-structured survival analysis (TSSA), was used to classify subjects into discrete subgroups that differed significantly in profiles of risk factors and incidence of IHD. On the basis of five characteristics--systolic blood pressure (SBP), high-density-lipoprotein cholesterol (HDL-C), 1-hour postload glucose levels, forced expiratory volume in 1 second (FEV1), and a family history score for heart disease--the TSSA algorithm partitioned the cohort into six discrete subgroups that formed three clusters of individuals with distinct IHD experience. Highest IHD incidence rates were experienced by a subgroup of 56 men with baseline SBP above 134 mm Hg and HDL-C levels lower than 33 mg/dL. No IHD events were observed in a subgroup of 117 men who had low SBP, high FEV1, and a negative family history of heart disease. Relationships to the twinning condition showed that for both zygosities, cotwin-pair members were in the same risk subgroup more often than expected; however, the overall difference between the frequency of monozygotic (MZ) and dizygotic (DZ) cotwins was relatively small. The highest MZ/DZ ratios of observed to expected cotwin-pair membership occurred in subgroups with the highest and lowest incidences of IHD, suggesting that these extremes of incidence are most likely to be genetically determined.

Aged↗
PubMed1994

Minimal genetic influences on plasma fibrinogen level in adult males in the NHLBI twin study.

Plasma fibrinogen was determined in 189 twins participating at the Indiana center during the third examination of the NHLBI twin study with a mean age of 63 years. Moderate heritability estimates were obtained from 44 complete MZ pairs and 39 complete DZ pairs. After adjustment of fibrinogen levels for age and other confounding variables related to cardiovascular disease risk, the maximum likelihood heritability estimate was only 30% (p = 0.03). Plasma fibrinogen was most strongly associated with smoking and the presence of diabetes. Omitting all subjects with diabetes or cardiovascular disease further reduced the heritability estimates slightly, and most path models including genetic parameters provided no significant improvement in fit over a model determined solely by random environmental effects. Our results are consistent with the environment rather than genetic influences having a greater influence on the level of plasma fibrinogen.

Aged↗
PubMed1994

Correlations of alcohol consumption with related covariates and heritability estimates in older adult males over a 14- to 18-year period: the NHLBI Twin Study.

Consistent maximum-likelihood heritability estimates of consumption of alcoholic beverages were observed at three separate times during a 14- to 18-year period in adult twin males initially aged 42-56 years in 1969-1973. Log transformation of the average number of drinks/week of the returnees to all three examinations was examined relative to potential covariates representing both antecedents of drinking alcohol and consequences of alcohol consumption. Significant relationships were noted for 38 of the covariates at one or more of the separate examinations, including positive correlations with smoking, coffee consumption, high-density lipoprotein cholesterol, mean corpuscular volume, systolic blood pressure, uric acid and behavioral measures, and negative correlations with blood urea nitrogen, red blood cell count, tea consumption, and tricep skinfolds. Analysis of the average alcohol consumption adjusted for nine independent covariates selected from multiple stepwise regression resulted in a modest decline in maximum-likelihood heritability estimates compared with unadjusted data, but little difference from heritability estimates obtained when abstainers from alcohol (no alcoholic beverages consumed at all three examinations) were excluded. The most striking effect of omitting abstainers from alcohol was the decline in the intraclass correlations in dizygotic twins. Bivariate analyses of alcohol and individual covariates revealed the phenotypic correlation between alcohol consumption and a measure of hostility was primarily environmental, that for high-density lipoprotein, smoking and coffee drinking with alcohol was primarily genetic, and the phenotypic correlation between alcohol consumption and mean corpuscular volume had both significant genetic and environmental correlations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Intellectual and psychosocial status of remedial students.

The Kaufman Brief Intelligence Test and Measures of Psychosocial Development were given to assess 49 remedial and 33 average college students. Significant differences were found between the two groups on intellectual and developmental variables. The results are discussed and concerns for staff noted.

Adult↗
PubMed1994

Genetic and environmental correlations between obesity and body fat distribution in adult male twins.

Genetic and environmental correlations between measures of obesity [body mass index (BMI)] and body fat distribution [waist/hip ratio (WHR) and subscapular/triceps ratio (SSTR)] were examined in 133 monozygotic and 129 dizygotic pairs of elderly white male twins, age 59 to 70 years, participating in the third cardiovascular examination of the National Heart, Lung, and Blood Institute Twin Study. The BMI, WHR, and SSTR fat measures were significantly correlated in these twins, with BMI more closely related to WHR (r = 0.52) than to SSTR (r = 0.18), and the WHR-SSTR association intermediate (r = 0.27). Multivariate genetic analyses of the three indexes using the LISREL modeling approach indicated a significant heritable component for each fatness variable, h2 = 0.66, 0.46, and 0.25 for BMI, WHR, and SSTR, respectively, and a significant correlation between genetic influences on BMI and WHR (genetic r = 0.51). The common genetic component accounted for 54% of the observed BMI-WHR correlation, suggesting that overall obesity and abdominal adiposity distribution are mediated to some extent by similar genetic influences. The genetic correlations between SSTR and BMI and between SSTR and WHR were not significantly different from zero, suggesting that genetic influences on skinfold distribution are independent of those on abdominal body fat and overall obesity. The genetic findings support the hypothesis that the WHR and SSTR indexes do not assess the same dimensions of fat patterning.

Adipose Tissue↗
PubMed1993

The NHLBI male veteran twin study data.

The National Heart, Lung and Blood Institute (NHLBI) twin study is a collaborative, longitudinal study of the role of genetic risk factors on subsequent cardiovascular disease processes in 514 pairs of white, male World War II and Korean veteran twins born between 1917 and 1927. This paper describes the sampling procedures and zygosity determination at the initial examination, participation by the cohort members at later examinations, and a summary of the variables provided for Genetic Analysis Workshop 8 (GAW8).

Aged↗
PubMed1993

The use of monozygotic and dizygotic twins to estimate the effects of inheritance on the levels of immunoglobulin isotypes and antibodies to phosphocholine.

In the elderly there is a pronounced increase in susceptibility to infectious disease. Evidence for particular immune deficits that result in susceptibility to specific agents is lacking, however, and there is little information on the degree to which differences in the susceptibility among the elderly are due to genetic versus environmental effects. A strong association has been observed between eventual fatal pneumonia and elevated levels of IgM antibody to phosphocholine (PC) levels at age 70. In this study we evaluated the heritability of IgM and IgG antibody levels to phosphocholine in the elderly using monozygotic and dizygotic male twins. We observed genetic regulation of serum levels of IgM antibody to PC, a finding which suggests that susceptibility of the elderly to fatal pneumonia may be heritable. Levels of total IgM were under separate genetic control and there was no genetic effect on IgG and IgA levels or levels of IgG antibody to phosphocholine.

Aged↗
PubMed1992

Long-term bone loss in men: effects of genetic and environmental factors.

OBJECTIVE: To identify environmental factors associated with bone loss in adult male twins and to determine the extent to which shared environmental characteristics affect estimates of the genetic influence on bone loss. DESIGN: A 16-year cohort study. SETTING: A midwestern university hospital. PARTICIPANTS: One hundred and eleven male veterans of World War II or the Korean conflict, born between 1916 and 1927. All were twins, with the sample comprising 48 pairs and 15 persons whose twin brothers were deceased or seriously ill. MEASUREMENTS: Bone mass and environmental characteristics (cigarette smoking, alcohol consumption, physical activity, dietary calcium intake, use of thiazide diuretics) measured at baseline and 16 years later. RESULTS: Rates of radial bone loss averaged 0.45% per year. Those who both smoked and used alcohol at levels greater than the median for the population had a rate of bone loss (10% in 16 years) twice the rate of those who were below the median level for both variables (5% bone loss, P = 0.003). Rates of bone loss were correlated within twin pairs, and these correlations were diminished 25% to 35% by adjustments for environmental influences on bone loss. However, statistically significant within-pair correlations remained (r = 0.4), which did not differ between monozygotic and dizygotic twin pairs after adjustments for smoking, alcohol use, dietary calcium intake, and exercise. CONCLUSIONS: Bone loss in men during mid-life is determined, at least in part, by environmental factors, including smoking, alcohol intake, and, possibly, physical activity. Rates of bone loss were similar within twin pairs, apparently because of a shared environment.

Alcohol Drinking↗
PubMed1992

Neonatal 6-OHDA lesions and rearing in complex environments: regional effects on adult brain 14C-2-deoxyglucose uptake revealed by exposure to novel stimulation.

Behavioral and neuromorphological data have suggested at least a partial interaction between the effects of norepinephrine-depleting neonatal 6-OHDA lesions and the effects of rearing in enriched environments. The present study examined the impact of both of these early manipulations upon regional brain uptake of 14C-2-deoxyglucose (14C-2DG) in adulthood. Newborn rats received 6-OHDA (50 mg/kg s.c.) or vehicle and, after weaning at 25 days, were reared in isolated versus enriched conditions. Regional brain 14C-2DG uptake was then examined at 70-80 days of age--either in the home cage or while animals were being exposed to novel, presumably arousing, stimulation. Ninety-seven brain regions were examined in eight separate groups. Results indicated that (1) Under baseline conditions, neither neonatal 6-OHDA nor differential rearing conditions produced widespread alterations in regional brain 14C-2DG uptake profiles. An overall enrichment effect was seen on only five brain areas, with rats reared in enriched environments showing lower levels of 14C-2DG uptake (-20% to -30%) than isolated rats. Neonatal 6-OHDA produced no main effect on 14C-2DG uptake in any brain region. (2) In contrast, when 14C-2DG uptake was assessed during exposure to a novel environment, five brain areas showed differential 14C-2DG uptake in 6-OHDA-treated rats, and 20 brain areas showed differential uptake in rats reared in enriched conditions. (3) No significant interaction effect on brain regional 14C-2DG uptake was observed between neonatal 6-OHDA and environmental complexity factors. These results are consistent with the notion that enduring effects of rearing and early 6-OHDA treatment may, independently, relate to a general reactivity factor. They also indicate that some effects of early neurochemical injury and subsequent experiential factors may not be apparent under normal resting conditions, but only become evident in the presence of appropriate "activating" stimulation.

Animals↗
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↗