bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Cincinnati lipid research clinic family study: Analysis of commingling and family resemblance for fasting blood glucose
Authors: Laskarzewski P. M. , Rao D. C. , Glueck C. J. , Nance Walter E. 
Published: June 2005

AbstractOur specific aim in this study was to investigate commingling and family resemblance for fasting blood glucose in 160 randomly selected white families from the Princeton School District Lipid Research Clinics Family Study. Adjustment of fasting blood glucose for the influence of age, sex, and the use of oral contraceptives and construction of indices were performed simultaneously using multiple regression methods. Path analysis was carried out, constructing an environmental index based on special diet usage, hematocrit, and obesity, which was also adjusted for the influences of age and sex. Commingling analysis and segregation analysis using the mixed model were also performed. Nearly 16% of the variance of fasting blood glucose was accounted for by age and sex. Obesity itself, which constituted the index, explained an additional 4% of the variance of fasting blood glucose. Significant genetic heritability for fasting blood glucose was documented by both path analysis and segregation analysis. In aggregate, we conclude that though there was a major familial vector accounting for within‐family aggregation of blood glucose, it was probably generated by a multifactorial component as compared to a major locus. Under the most parsimonious model, path analysis estimated the genetic and cultural heritabilities as h2 = .39 ± .08 and c2 = .06 ± .03., respectively.
Familial resemblance on the thurstone activity scale, systolic blood pressure, and total cholesterol among first degree relatives of subjects with and without coronary heart disease
Authors: Carmelli Dorit , Rosenman Ray , Rao D. C. 
Published: June 2005

AbstractAn investigation of the pattern of familial resemblance of three different risk factors assessed in families of coronary heart disease (CHD) patients and controls is presented. The fathers of these families participated in the Western Collaborative Group Study that first established the type A/B behavior pattern as an independent risk factor for CHD. A recently developed methodology, the Structured Exploratory Data Analysis (SEDA), was implemented to examine parental interaction, parent‐offspring closeness, assymmetries in transmission, and other differences in the pattern of familial similarities among family members of case and control subjects. The analysis performed revealed pronounced parent‐child similarity for total serum cholesterol values in both case and control families; spouse closeness and parent‐child resemblance for systolic blood pressure measurements only in control families; and sex asymmetries in the parent‐child closeness on pace of activity, which also differed between case and control families. The results of this investigation underscore the value of examining the joint pattern of familial resemblance of a number of risk factors as a means for differentiating between cultural and biological factors affecting familial aggregation of CHD.
A comparison of sib‐pair linkage tests for disease susceptibility loci
Authors: Blackwelder William C. , Elston Robert C. , Rao D. C. 
Published: June 2005

AbstractAn analytical study is conducted of the properties of statistical tests to detect linkage between a disease locus and a very polymorphic marker locus when data on sib pairs are available. In most instances the most powerful test is the test based on the mean number of marker alleles shared identical by descent by the two members of a sib pair, and the most efficient sampling strategy is almost always to sample only pairs with both sibs affected. We show it is valid to use the information from all possible sib pairs as though they came from separate families when data on sibships of size three or larger are available, though more power may be obtained if different weights are given to the different sibship sizes.
Genetic and environmental influences on the size and number of cells in the blood
Authors: Whitfield J. B. , Martin N. G. , Rao D. C. 
Published: June 2005

AbstractThe heritabilities of human blood cell characteristics were estimated in a study of 206 pairs of young adult twins, male and female. White cell numbers, indices related to circulating red cell mass (haemoglobin, red cell count, and haematocrit), and platelet numbers and size all appeared to be accounted for by genetic and nonshared environmental influences only. Mean cell volume (of the erythrocytes) appeared to be influenced by environmental factors shared by siblings as well as the other two sources of variation.Correlation between red cell count and haemoglobin is modulated by both genetic and environmental factors, but the negative correlation between red cell numbers and size is due mainly to genetic factors independent of those influencing haemoglobin. A significant negative correlation also exists between platelet numbers and size.In males, alcohol consumption increased mean cell volume, and genetic factors influencing alcohol consumption are partly responsible for the correlation between them.
Familial aggregation in chronic obstructive pulmonary disease: Use of the loglinear model to analyze intermediate environmental and genetic risk factors
Authors: Khoury Muin J. , Beaty Terri H. , Tockman Melvyn S. , Self Steven G. , Cohen Bernice H. , Rao D. C. 
Published: June 2005

AbstractTo examine the contribution of environmental and genetic risk factors to familial aggregation in chronic obstructive pulmonary disease (COPD), 325 first‐degree (ld) relatives and 56 spouses of 150 COPD patients were compared with 222 ld relatives and 49 spouses of 107 nonpulmonary patient controls for the prevalence of two clinical outcomes: 1) airways obstruction (AO; 1‐sec forced expiratory volume < 68% of forced vital capacity) and 2) chronic bronchitis (CB; cough and sputum for 3+ months per year for 2+ years). The loglinear model was used to study direct and indirect (ie, those mediated by other risk factors) components of familial aggregation. Three risk factors were found to be independently associated with CB and/or AO: α1‐antitrypsin deficiency (PiZ allele), personal cigarette smoking, and parental cigarette smoking. Because ld relatives of COPD patients were more likely to have a PiZ allele, be heavy smokers (1 + packs per day), and be exposed to parental smoking than ld relatives of controls, these three factors also constitute indirect components of familial aggregation. However, after controlling for the three factors, ld relatives of COPD patients were more likely to have AO and CB than ld relatives of controls (direct component). This direct component might have a genetic basis, because no such association was found when spouses instead of ld relatives were compared. Thus, both shared environmental factors (personal and passive smoking) and shared genetic factors (α1‐antitrypsin and a possible direct genetic component) contribute to familial aggregation in COPD. The loglinear model provides a useful tool for analyzing familial aggregation in diseases of multifactorial etiology.
The collaborative Lipid Research Clinics family study: Biological and cultural determinants of familial resemblance for plasma lipids and lipoproteins
Authors: Namboodiri K. K. , Kaplan E. B. , Heuch I. , Elston R. C. , Green P. P. , Rao D. C. , Laskarzewski P. , Glueck C. J. , Rifkind B. M. , Skolnick M. H. 
Published: June 2005

AbstractThis paper reports on the biological and cultural determinants of total, LDL, and HDL cholesterol, and triglyceride (TC, LDL‐C, HDL‐C, TG) levels using a general linear model on randomly selected family data collected during 1975–1978 at nine North American Lipid Research Clinics. Initially, the analyses were clinic‐specific to assess the importance of genetic and cultural transmission, marital resemblance, and other determinants of these traits and then were made jointly to identify the nature and sources of any heterogeneity between clinics. There was evidence of significant genetic and cultural factors for all traits in most clinics. Clinic heterogeneity was also significant, but excluding one clinic reduced the heterogeneity considerably. The genetic (h2) and cultural (c2) heritabilities for the remaining eight clinics were homogeneous with pooled estimates of h2 of .556 ± .028, .539 ± .028, .485 ± .029, and .358 ± .028, and of c2 of .029 ± .006, .033 ± .006, .075 ± .008, and .089 ± .009 for TC, LDL‐C, HDL‐C, and TG, respectively. Among the traits, HDL‐C exhibited the most difference among clinics, and both HDL‐C and TG showed the largest cultural heritability. The relevance of these and similar studies in a broader understanding of the determinants of plasma lipids and lipoproteins is discussed.
Familial analysis of qualitative traits under multifactorial inheritance
Authors: Rice John , Reich Theodore , Elston R. C. 
Published: June 2005

AbstractThe analysis of family data is described for qualitative multifactorial traits. For such a trait, affectational status is determined by an underlying liability distribution with one or more thresholds. The distribution of families (either selected at random or through probands) is used to estimate sex‐specific parent‐offspring and sibling correlations in liability and the prevalence in each sex. In contrast to using pairs of relatives, this approach permits estimation of age‐specific population prevalences without a control sample. Moreover, by allowing for sex‐specific correlations and a correlation between mates, path analysis can be used to model and test various cultural transmission models in addition to polygenic inheritance. Parameter estimation, hypothesis testing, and a goodness‐of‐fit test for path analytic models are described, and a computer program implementing these procedures is outlined.
The information content of phase‐known matings for ordering genetic loci
Authors: Timothy Bishop D. , Rao D. C. 
Published: June 2005

AbstractThis analysis evaluates the amount of linkage information that can be obtained for ordering three loci. The information contents of data collected on three independent pairwise samples of two loci, and data obtained jointly from three loci in a single set of individuals are compared. The level of support of the maximum likelihood order and the interpretation of that support are also examined.
Segregation analysis of hereditary nonpolyposis colorectal cancer
Authors: Bailey‐Wilson Joan E. , Elston Robert C. , Schuelke Guy S. , Kimberling William , Albano William , Lynch Jane F. , Lynch Henry T. , Rao D. C. 
Published: June 2005

AbstractSegregation analysis of eleven families comprising 2762 individuals indicated compatibility of the data with segregation of a major autosomal dominant gene for hereditary nonpolyposis colorectal cancer. It was estimated that between 71% and 79% of the gene carriers were susceptible and had age of onset that was normally distributed with mean about 47 and standard deviation about 10 years. There was a low frequency of sporadic cases at the older ages, a little less than four percent of nongene carriers being affected by age 80. No significant differences were found between the families exhibiting endometrial cancer (cancer family syndrome) and those not exhibiting endometrial cancer (hereditary site‐specific nonpolyposis colonic cancer).
Testing for familial aggregation of a dichotomous trait
Authors: Hunt Steven C. , Hasstedt Sandra J. , Williams Roger R. , Rao D. C. 
Published: June 2005

AbstractFamilial aggregation of a disease is usually tested using a chi square statistic on a sample of pairs of related individuals. Standard sampling designs often produce dependent observations (multiple pairs from the same family), possibly inflating the numerical value of the statistic over the value independent observations would produce. This article presents a derivation of the chi square statistic for familial aggregation, allowing for dependency because of the inclusion of the same and related persons in multiple pairs. For intraclass aggregation, the standard chi square statistic is appropriate. For interclass aggregation, an adjustment to the standard chi square statistic is needed; the adjustment depends on the disease frequency and the intraclass aggregation within each class.
Heritability of clinical chemistries in an older twin cohort: The NHLBI Twin Study
Authors: Kalousdian Sona , Fabsitz Richard , Havlik Richard , Christian Joe , Rosenman Ray , Rao D. C. 
Published: June 2005

AbstractHeritability analyses were performed with clinical chemistry data collected on 360 twin pairs of white, middle‐aged male veterans during the second examination of the NHLBI Twin Study, a multicenter study of cardiovascular disease risk factors. Significant genetic variability was present for albumin, alkaline phosphatase, blood urea nitrogen, 1‐hr postload glucose, phosphorus, total protein, and uric acid. Calcium and aspartate aminotransferase had significantly different means by zygosity, which precluded further analysis. Total bilirubin and lactate dehydrogenase did not show evidence for genetic variation at this examination. Comparisons are made to results from similar twin studies and the first examination of the NHLBI Twin Study. Heritability estimates for phosphorus and blood urea nitrogen exhibited marked stability across studies, while heritability estimates for total bilirubin, total protein, and uric acid decreased in older study populations. The heritability of 1‐hr postload blood glucose decreased from 0.88 at the first NHLBI examination to 0.52 at the second one. Interpretation of these results requires consideration of possible selection biases, methodologic and demographic issues, and the view that for some clinical chemistries, biological aging along with prolonged environmental exposures may alter the amount of phenotypic variation explained by the additive effect of genes alone.
Genetic epidemiology of myotonic dystrophy
Authors: Mostacciuolo M. L. , Barbujani G. , Armani M. , Danieli G. A. , Angelini C. , Rao D. C. 
Published: June 2005

AbstractPrevalence rate of myotonic dystrophy (DM) was estimated in a large sample of the Italian population. Segregation analysis of the affected families suggests that subjects showing minor clinical signs, even in the absence of myotonic features, should be considered as bearers of the DM trait. An apparent excess of normal sibs among the offspring of DM subjects may be due to the late onset of the disease and possibly to a partial loss of affected individuals from the sample before diagnosis. Prevalence rate of DM in this study is estimated between 69 to 90 per million inhabitants; accordingly, DM might be the most frequent inherited neuromuscular disorder in human populations.
Age and prevalence of sickle‐cell trait in a large ambulatory population
Authors: Castro Oswaldo , Rana Sohail R. , Bang Ki Moon , Scott Roland B. , Rao D. C. 
Published: June 2005

AbstractWe performed hemoglobin electrophoresis in 30,400 apparently healthy black individuals in the Washington D.C. Metropolitan area, who were participating in a community based sickle‐cell screening program during the period 1978–1985. The overall prevalence of sickle‐cell trait was 6.7%. The frequency of sickle‐cell trait in various age groups, which included young children, adults, and individuals over 65 years of age, ranged from 6.4 to 7.4%. There were no statistically significant differences in the prevalence of sickle‐cell trait among the various age groups, nor did we detect a significant trend for increasing or decreasing sickle cell frequency with advancing age (P = 0.418). Thus, in this population sickle‐cell trait appears to have no effect on longevity. If the various complications of sickle‐cell trait reported in the literature are not fortuitous, their frequency and/or severity must be too low to affect prevalence figures.
Sex differences in affective disorder: Genetic transmission
Authors: Faraone Stephen V. , Lyons Michael J. , Tsuang Ming T. , Rao D. C. 
Published: June 2005

AbstractEpidemiological studies have consistently found women to be at greater risk than men for affective disorders. This sex effect may help clarify genetic transmission and heterogeneity. Data from eight family studies of unipolar and eight family studies of bipolar probands were used to calculate family resemblance sex ratios. These observed sex ratios were then compared to sex ratios predicted by X‐linked and nonfamilial effects models. Maximum likelihood estimation of competing models revealed that X linkage was not a good fit to the unipolar data. The bipolar studies were not consistent with either the X‐linked or the nonfamilial effects model.
Path analysis of seven fear factors in adult twin and sibling pairs and their parents
Authors: Phillips Kay , Fulker David W. , Rose Richard J. , Eaves Lindon J. 
Published: June 2005

AbstractA multivariate path model of genetic and environmental transmission, used to derive expected covariances among adult twin and sibling pairs and their parents, was fitted to fear factor data from 250 twin families and 91 sibling families, with the use of a maximum‐likelihood estimation procedure. The full model, with 259 free parameters, provides for parental cultural transmission, common twin and sibling environment, genotype‐environment correlation, direct assortative mating, and genetic and environmental correlations. Significant effects were indicated for heritable transmission of common fears and phobias, and a single genetic factor accounted for most of the genetic covariance among the traits. Moderately high levels of common twin environment and a small effect for direct isomorphic marital assortment were also found. There was no evidence for cultural transmission, genotype‐environment correlation, or common sibling environment.
Biological and cultural sources of familial resemblance in plasma lipids: A comparison between North America and Israel—the lipid research clinics program
Authors: Bucher K. D. , Friedlander Y. , Kaplan E. B. , Namboodiri K. K. , Kark J. D. , Eisenberg S. , Stein Y. , Rifkind B. M. , Rao D. C. 
Published: June 2005

AbstractHeterogeneity in determinants of familial resemblance of lipid and lipoprotein levels between populations in North America and Israel was investigated using path analysis. A common protocol, identical measurement techniques, and the same statistical procedures were used in the two samples. Both genetic (h2) and cultural (c2) determinants of inheritance were significant for all lipid variables in the two studies. Genetic and cultural heritability of total cholesterol (h2 = 0.61, c2 = 0.02), low‐density lipoprotein cholesterol (h2 = 0.59, c2 = 0.02), and high‐density lipoprotein cholesterol (h2 = 0.55, c2 = 0.06) did not differ significantly between North America and Israel, while there was a significant difference for triglyceride (h2 = 0.41, c2 = 0.07 in North America; h2 = 0.61, c2 = 0.05 in Israel). Secondary parameters of the path model describing intrafamilial environmental relationships differed between the two countries. In particular, there was a higher correlation between marital environments in Israel for all traits except triglyceride, and a larger effect of father's environment on offspring's environment in Israel for all traits. Within both populations, variation of plasma lipids and lipoproteins was mostly explained by genetic factors and random unmeasured environmental factors. The contribution of common family environment was found to be small, though statistically significant. This is probably due to homogeneity of the distribution of familian environmental determinants within both countries.
Segregation analysis of leprosy in families of northern Thailand
Authors: Wagener Diane K. , Schauf Victoria , Nelson Kenrad E. , Scollard David , Brown Arthur , Smith Trevor , Borecki Ingrid B. 
Published: June 2005

AbstractSixty‐three families with multiple instances of leprosy were identified through a major leprosy treatment center in northern Thailand. Complex segregation analyses for single major genes or polygenic inheritance were performed using the maximum‐likelihood routine POINTER to determine the most likely etiologic model of genetic susceptibility. Liability differences between men and women were considered in these models. When individuals were considered to be affected because they had any form of leprosy, a generalized major gene model with nearly dominant parameters on the liability scale, but additive penetrances, was found to be the most likely. When only those individuals who had tuberculoid forms of leprosy were considered to be affected, a recessive model was found to be the most likely; however, the discrimination between various models was poor. Further analyses are necessary to delineate genetic mechanisms to explain these apparently divergent results. In particular, methods of testing two locus models should be considered.
Segregation and linkage analysis of nine Utah breast cancer pedigrees
Authors: Bishop D.T , Cannon‐Albright L. , McLellan T. , Gardner EJ , Skolnick MH , Rao D. C. 
Published: June 2005

AbstractThe analysis of nine Utah families that were ascertained for clusters of breast cancer cases is reported. Segregation analysis of an inherited susceptibility to breast cancer shows two distinct maximum likelihood solutions that have almost equal likelihood. One model indicates that most females had zero risk for breast cancer, but 10% of the female population had risks much greater than the Utah age‐specific incidence rates. The other model indicates that most females have a risk defined by the Utah rates for breast cancer, but a rare dominant gene is segregating for increased susceptibility to breast cancer. Our analysis shows that linkage results under the two models are consistent in sign but not in magnitude. No evidence for linkage was found with the 14 marker loci examined. In addition to demonstrating distortion of linkage results from ignoring sporadic cases, this analysis shows the inherent difficulty of obtaining parameter estimates for segregation analysis when families are ascertained from a cluster of cases.
Alcohol effects on the percentage of beta waves in the electroencephalograms of twins
Authors: Christian Joe C. , Li Ting‐Kai , Norton James A. , Propping Peter , Yu Pao‐Lo , Rao D. C. 
Published: June 2005

AbstractElectroencephalogram (EEG) recordings were made from 26 pairs of monozygotic (MZ) and 26 pairs of dizygotic (DZ) adult male twins, before and after alcohol ingestion. After a baseline EEG and a light breakfast, 1.2 ml/kg of ethanol was given orally over 15 min and the EEG repeated four times at hourly intervals. Alcohol caused a significant drop in the percentage of beta waves (14–30 cycles/sec) during the 1st hr. For the percentage of beta waves in 38 pairs of twins with complete data, MZ twin beta‐wave intraclass correlations (RMZ) ranged between 0.85 and 0.91 before and after alcohol, but the DZ intraclass correlations (RDZ) started at 0.54 and fell to 0.05 at 2 hr after alcohol before recovering to baseline levels. These correlations resulted in heritability estimates [2(RMZ‐RDZ)] of 0.68 at baseline and 1.73 at 2 hr. A heritability of 1.43 was found for the 1st hr drop in percentage of beta waves (RMZ = 0.78, RDZ = 0.06). These unrealistically high heritabilities, due to RDZ's approaching 0.0, suggest a failure of assumptions in the linear twin model that was used. Also, these findings are similar to, but more exaggerated than, findings in resting EEG's and visually evoked EEG potentials of twins and are compatible with the influence of gene interactions.