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B H Cohen

Publications and source records attributed to B H Cohen.

At least 73 records · Page 4Linked to original sources
PubMed1987

Inbreeding and prereproductive mortality in the Old Order Amish. III. Direct and indirect effects of inbreeding.

Direct and indirect (mediated by biologic factors) effects of inbreeding on prereproductive mortality (death before age 20 years) were investigated in a case-control study conducted in the Lancaster County, Pennsylvania, Old Order Amish. A total of 211 cases of prereproductive death between 1969 and 1980 and 213 live controls were compared for differences in inbreeding coefficients, congenital malformations, birth weight, gestational age, birth complications, and other demographic factors, obtained by linking cases and controls to vital records and the Amish genealogic registry dating back to the 1700s. Inbreeding coefficients (F) for cases and controls were computed using the path method of tracing common ancestors in the multigenerational pedigrees. Close inbreeding (F greater than or equal to 1/64) was a significant risk factor for prereproductive mortality; odds ratio = 1.55. Using the log-linear model, the effect of close inbreeding on mortality was found to be mediated by three indirect casual mechanisms: Regardless of case-control status, inbreeding was significantly related to congenital malformations (recorded at birth), intrauterine growth retardation (birth weight less than 10th percentile for gestational age), and the occurrence of other deaths in the sibship. In turn, each of these factors was independently related to mortality regardless of inbreeding. No significant direct effect of inbreeding remained after adjustment for these factors. There were no effects of inbreeding on prematurity (less than 37 weeks), or birth complications. This study suggests that inbreeding increases the risk of prereproductive mortality by increasing the risk of intrauterine growth retardation and congenital malformations but not prematurity. The log-linear model provides a useful approach to the analysis of direct and indirect risk factors using biologic mechanisms.

Congenital Abnormalities↗
PubMed1986

Interaction of genetics and epidemiology in the literature.

To evaluate the extent of interaction between genetics and epidemiology in studies reported in the literature, we reviewed all the "familial/genetic" papers published in a standard epidemiology journal (American Journal of Epidemiology, AJE) and all the "epidemiology" papers published in a standard human genetics journal (American Journal of Human Genetics, AJHG) between 1966 and 1984. A variety of medline subject headings were used in this search. Computerized listings of titles, subject headings, and abstracts were reviewed. It could be shown that familial/genetic papers constituted 4.3% of all papers published in AJE and epidemiology papers constituted 16.4% of papers published in AJHG. Over time, familial/genetic studies published in AJE increased both in number and in proportion of all papers, and more family studies are using complex statistical genetic techniques. On the other hand, epidemiology papers published in AJHG did not increase in number over time, and actually decreased in relation to all papers. These papers were mostly either descriptive (eg, defining frequencies of Mendelian traits in populations) or analytical (eg, defining risk factors for chromosomal abnormalities, and other reproductive outcomes). This analysis suggests that epidemiologic methods have been widely used in the genetic literature, and that genetic methods are gaining more access to the recent epidemiology literature. Because of increasing recognition of the role of genetic factors in disease, there is a growing need to incorporate both genetic and epidemiologic methods in etiologic studies of complex disorders.

Epidemiology↗
PubMed1986

Genetic-environmental interactions in chronic airways obstruction.

To examine patterns of interaction between cigarette smoking and genetic factors in relation to airways obstruction, cross sectional data were analysed on 1787 white non-patient adult participants in a genetic-epidemiological study of airways obstruction (AO), defined as one-second forced expiratory volume FEV1 less than 68% of forced vital capacity FVC. Interaction was examined between smoking and each of four factors previously found to be related to AO: alpha-1 antitrypsin (PiZ allele), ABO blood groups (A antigen), ABH non-secretor status, and first degree relationship to a COPD or lung cancer patient. Multiple linear regression was used to test for interaction and adjust mean FEV1 (as a per cent of FVC) and prevalence of AO for age, sex, socioeconomic status, coffee and alcohol intake. Statistical interaction was observed between smoking (measured in pack-years) and two genetic factors (presence of blood A antigen and the family history). At higher pack-year levels, those individuals with the A antigen or the family history, but especially those with both factors had a much lower mean FEV1/FVC % and a much higher prevalence of AO than expected based on a simple additive model. On the other hand, there was no interaction between smoking and PiZ allele, or smoking and ABH secretor status. The findings suggest a possible biological interaction between cigarette smoke and the airways of individuals with blood group A antigen and familial lung disease. The findings also emphasize the role of genetic-environmental interactions in chronic diseases of multifactorial aetiology.

ABO Blood-Group System↗
PubMed1986

Application of odds ratio regression models for assessing familial aggregation from case-control studies.

A regression model for estimating covariate effects on odds ratios to test for familial aggregation of common disease in first-degree relatives of cases and controls is presented and illustrated by using family data from a study of chronic obstructive pulmonary disease. These estimators are in essence an extension of the Mantel-Haenszel estimator of odds ratio but do not require the assumption of independence among relatives. A robust test statistic for possible effects of covariates such as the matching variables for cases and controls on odds ratio is also presented. In data on 156 adult first-degree relatives of 28 cases with demonstrated airway obstruction and 28 controls matched for age, sex, race, and hospital status, there appeared to be a difference in the odds ratio among families of black and white case-control pairs. However, the small sample size available prevents conclusive interpretation of this observation.

Adult↗
PubMed1985

Variance components analysis of forced expiration in families.

Familial aggregation of forced expiration (as measured by forced expiratory volume in 1 sec (FEV1) and the ratio of this to total forced vital capacity (FEV1/FVC) was analyzed in 439 adult members of 108 families ascertained through control patients who had participated in a genetic and epidemiologic study of chronic obstructive pulmonary disease. Residual values for both FEV1 and FEV1/FVC obtained from regression on age, sex, race, and cigarette smoking (and height for FEV1) were used in a variance components analysis to assess the relative importance of genetic and nongenetic factors influencing familial aggregation of pulmonary function among adults. For both residual FEV1 and residual FEV1/FVC, the "best" model among a series of genetic and nongenetic models was a simple additive genetic model. A modified score test, which is robust to the assumption of multivariate normality, was used to test the significance of these estimated components. Under the most parsimonious model, additive genetic variation accounted for 28% of the variation in residual FEV1 in 108 families and 24% of the variation in residual FEV1/FVC. After outlying individuals were identified by examining goodness-of-fit statistics, the simple genetic model still gave the best fit to these data. There was little indication of non-normality in FEV1 in these families; however, FEV1/FVC did show evidence of non-normality when examining goodness-of-fit statistics. This genetic component contributing to the distribution of forced expiration may be a factor in the familial aggregation of certain respiratory diseases.

Adult↗
PubMed1985

Familial aggregation in chronic obstructive pulmonary disease: use of the loglinear model to analyze intermediate environmental and genetic risk factors.

To examine the contribution of environmental and genetic risk factors to familial aggregation in chronic obstructive pulmonary disease (COPD), 325 first-degree (1d) relatives and 56 spouses of 150 COPD patients were compared with 222 1d 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 less than 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: alpha 1-antitrypsin deficiency (PiZ allele), personal cigarette smoking, and parental cigarette smoking. Because 1d 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 1d relatives of controls, these three factors also constitute indirect components of familial aggregation. However, after controlling for the three factors, 1d relatives of COPD patients were more likely to have AO and CB than 1d relatives of controls (direct component). This direct component might have a genetic basis, because no such association was found when spouses instead of 1d relatives were compared. Thus, both shared environmental factors (personal and passive smoking) and shared genetic factors (alpha 1-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.

Biometry↗
PubMed1985

Effects of pulmonary function on mortality.

Survivorship data from a 24 year longitudinal study of 874 male volunteers in the Baltimore Longitudinal Study of Aging were used to assess the role of pulmonary function on total mortality. Even when age and smoking were considered, the ratio of forced expiratory volume in 1 sec to its predicted value was significantly associated with mortality from all causes. Individuals with poorer pulmonary function showed greater mortality during the follow-up period of this study. This relationship was also seen among never smokers in this sample, further supporting the hypothesis that impaired pulmonary function is itself a predictor of total mortality and may contribute to a number of disease processes.

Adolescent↗
PubMed1985

Acute intraocular pressure response to argon laser iridotomy.

Argon laser iridotomy (ALI) was performed in 50 eyes for prophylactic treatment of anatomically narrow iridocorneal angles and in 50 eyes for therapy of chronic angle-closure glaucoma. Intraocular pressure was increased 6 mmHg or more 1 to 2 hours after ALI in 19 of 50 eyes with anatomical narrow iridocorneal angles and in 23 of 50 eyes with chronic angle-closure glaucoma. Increases greater than 20 mmHg over baseline value occurred in 5 of 50 eyes with narrow iridocorneal angles and in 7 of 50 eyes with chronic angle-closure glaucoma. A clinically significant increase in intraocular pressure (defined as a pressure 30 mmHg or greater and 40% or more increased over the pre-laser value) occurred 1 to 2 hours after ALI in 11 of 50 eyes with narrow iridocorneal angles and in 17 of 50 eyes with chronic angle-closure glaucoma. There was no statistical difference (chi square P greater than 0.3) in the incidence of this complication in the two groups. Additional medical therapy was effective in lowering the acute laser-induced elevation in intraocular pressure. Patient diagnosis, patient demographics, preoperative glaucoma medication and laser treatment parameters did not predict which eyes would develop this complication. Eyes which did not have a clinically significant elevation in intraocular pressure 1 to 2 hours after ALI did not show a later increase at 24 hours.

Female↗
PubMed1985

Nitrogen washout and mortality.

We studied the association between different tests of pulmonary function and subsequent mortality. Subjects were drawn from an epidemiology study of chronic obstructive pulmonary disease. Between 1971 and 1976, 2,539 nonpatient adults had tests of forced expiration, diffusing capacity, and single-breath nitrogen washout. By 1981, 115 of those subjects had died, including 3 from known lung disease. In assessing the relationship between lung function and mortality, the following tests of pulmonary function were examined: forced expiratory volume in one second as a percentage of forced vital capacity, forced expiratory volume divided by height cubed, slope of phase III from the single-breath nitrogen test, closing capacity, diffusing capacity for CO, and the ratio of maximal flow at 75% to that at 25% vital capacity. When adjustments for age and smoking were made, slope of phase III was strongly associated with mortality, even more so than tests of forced expiration. There are two possible explanations for this striking relationship between these observed abnormalities of lung function and subsequent overall mortality (which is largely from nonpulmonary disease): the lungs may serve to protect other systems of the body and therefore poor pulmonary function may contribute to a number of diseases leading to death, or lung function may merely reflect existing disorders in other systems of the body, and the observed association between mortality and pulmonary function is a byproduct of nonpulmonary diseases.

Adult↗
PubMed1985

Retinopathy of dermatomyositis.

A recent case of childhood dermatomyositis with striking retinopathy is reported. The patient's vision was initially at the 20/80 to 20/100 level with associated macular edema and extensive cotton-wool infarction of the retina. Visual recovery to the level of 20/20 in both eyes was achieved following treatment with high-dose corticosteroids.

Child, Preschool↗
PubMed1985

Genetic and environmental effects on the development of myopia in Chinese twin children.

In order to assess the relative and interactive importance of genetic and environmental components on the development of myopia in Chinese school children aged from 10 to 15 years, a population-based sample of 361 same-sexed twin pairs recruited through stratified cluster sampling was studied. Zygosity of twin pairs was determined by Mendelian traits, red cell antigen systems, and continuous dermatoglyphic characteristics; while myopia was diagnosed by both objective and subjective techniques. Studying and reading habit was obtained from cotwins and their parents through a life style questionnaire. Age-sex-adjusted concordance rate derived from multiple regression equation was used in the analysis. Conventional comparison of intrapair concordance between monozygotic (MZ) and dizygotic (DZ) twins was used to assess the importance of a genetic component in the determining of myopia, and a significant genetic influence was observed. Environmental influence on myopia was evaluated through MZ cotwin method, and MZ cotwins with concordant studying and reading habits were significantly more concordant in myopia than those MZ cotwins with discordant habits. The possible effect of gene-environment interaction on myopia was explored, and concordance in myopia was found significantly associated with the interaction between zygosity and habit of studying and reading. These observations suggested that the impact of the environmental factor on the development of myopia may be influenced by genotype, and vice versa.

Adolescent↗
PubMed1984

Genetic variance and heritability of cardiovascular risk factors in Chinese adolescent twins.

In order to estimate genetic variance and heritability of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels, a total of 235 (79 male and 82 female MZ, 41 male and 33 female DZ) twin pairs, recruited from 12 junior high schools in Taipei city, were studied. Statistically significant genetic variance observed for SBP, DBP, serum cholesterol and triglycerides persisted after adjustment for age and anthropometric characteristics. However, further adjustment for dietary preference, beverage consumption, and other host and environmental factors gave different results: genetic variance of adjusted SBP and DBP was still significant, while significance was found only in males for cholesterol and in neither males nor females for triglycerides. Heritability estimates of unadjusted SBP, DBP, cholesterol and triglycerides were 0.27, 0.45, 0.21 and 0.41, respectively, for males, and 0.15, 0.42, 0.41 and 0.82, respectively, for females. After adjustment for age, anthropometric characteristics, host and environmental factors, the heritability estimates of SBP, DBP and cholesterol were 0.64, 0.72 and 0.50, respectively, for males, and 0.40, 0.60 and 0.37, respectively, for females.

Adolescent↗
PubMed1984

Environmental effects on cardiovascular risk factors in Chinese adolescent monozygotic twins.

The monozygotic (MZ) cotwin control method was employed to elucidate possible environmental determinants of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. A population-based twin sample of 73 male and 77 females MZ twin pairs was recruited from 12 junior high schools in Taipei city. Intrapair differences in blood pressure were negatively associated with intrapair difference in vegetable preference, attaining significance for DBP in males and SBP in females. Cholesterol was positively associated with milk consumption and preference for sweets, fried foods, meat and fish. A negative association was also observed between cholesterol and vegetable preference. These associations for cholesterol were significant in males only. Triglyceride level negatively associated with preferences for sweets and vegetable, attaining significance for vegetables in both males and females and for sweets in males only.

Adolescent↗
PubMed1984

Effects of gene-environment interactions on cardiovascular risk factors in Chinese adolescent twins.

A population-based sample of 73 male and 77 female monozygotic (MZ), and 41 male and 33 female dizygotic (DZ) Chinese adolescent twin pairs were studied to assess effects of gene-environment interactions of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels. Intrapair concordance in BP levels was found to be significantly associated with the interaction of zygosity and salty foods preference and also with that of zygosity and vegetable preference. A consistently positive and statistically significant association was observed between the intrapair difference in serum cholesterol and the interaction of zygosity and animal organ preference; while intrapair concordance in serum cholesterol was associated with the interaction of zygosity and milk consumption. Intrapair difference in serum triglycerides was associated with the interaction of zygosity and fish preference, and a significant association was also found between the intrapair concordance in serum triglycerides and the interaction of zygosity and sweets preference. These observations suggest that the impact of these environmental agents may be influenced by the genotype.

Adolescent↗