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Biomedical subjects

R W Haile

Publications and source records attributed to R W Haile.

At least 73 records · Page 4Linked to original sources
PubMed1993

A linkage analysis of D17S74 (CMM86) in thirty-five families with premenopausal bilateral breast cancer.

We report here results of a linkage analysis of a marker in 35 families in which the proband had premenopausal bilateral breast cancer. This group is of particular interest given their high family risk and the question of etiological heterogeneity. Probands were ascertained from cancer registries in Los Angeles County and Connecticut and major hospitals in Montréal and Québec. Assuming no residual heterogeneity and summing lod scores over all families, we obtained strong evidence against tight linkage (e.g., lod score at theta = 0.000001 is -3.39). To address the issue of heterogeneity, we performed admixture and predivided sample analyses. Using an admixture model we were able to reject the hypothesis of no linkage versus that of linkage with homogeneity (P = 0.045). However, we were unable to reject the hypothesis of no linkage versus linkage with heterogeneity (P = 0.119) or to distinguish between linkage with homogeneity and linkage with heterogeneity (P = 0.500). Predivided sample analyses based upon age of onset, pathological characteristics, time between diagnoses of the breast cancers in each bilateral proband, and the span of ages at diagnoses within a family did not discriminate between apparently linked and unlinked families.

Age Factors↗
PubMed1993

HPV DNA and the risk of squamous intraepithelial lesions of the uterine cervix in young women.

A population-based case-control study of college students was undertaken to estimate the effect of a positive clinical test for human papillomavirus (HPV) DNA (the Virapap test) on the rate of squamous intraepithelial lesions (SIL) of the uterine cervix. When age, multiple lifetime sexual partners, and oral contraceptive use were controlled by logistic regression, the adjusted odds ratio (OR) for a positive Virapap test was 7.3 (3.3, 17) for a cytologic diagnosis of SILs and 3.4 (1.4, 8.5) for a cytologic diagnosis of squamous intraepithelial lesions of undetermined significance (equivocal atypia). When case status was defined as patients whose Pap smears were confirmed histologically as high-grade SIL, the adjusted OR was 10.3 (3.3, 32), reflecting the high proportion of individuals with SILs who were harboring high-grade squamous intraepithelial lesions. These results confirm the many previous findings of a strong association between HPV DNA, and demonstrate that strength of the association persists when important confounding variables are controlled. This suggests a causal role for HPV in cervical neogenesis. Believing that HPV infection is a major causal agent for cervical cancer precursors suggests that in this time of rapidly increasing HPV prevalence, especially among young persons, the incidence of cervical neoplasia will rise. This underscores the importance of increasing the availability, usage, and perhaps the frequency of Pap smear screening.

Adolescent↗
PubMed1992

Oral contraceptives and premenopausal bilateral breast cancer: a case-control study.

We estimated the effect of oral contraceptive (OC) use on premenopausal bilateral breast cancer in a matched case-control study. One hundred forty-four cases were identified from population-based registries of Los Angeles County, California, and of Connecticut and from the major hospitals in Montreal and Quebec City. Matched controls were the unaffected sisters of the cases. When age was included in the model, ever-use of OCs for 1 year or more was associated with an odds ratio 1.7 (95% confidence interval = 1.0-2.9). The odds ratios associated with 1-2, 3-6, and 7 years of use were 1.2 (0.61-2.4), 2.5 (1.2-5.3), and 2.0 (0.93-4.2), respectively. Too few women had used OCs before their first full-term pregnancy or before age 25 for these estimates to be informative. Restricting the analyses to women who had ever given birth yielded an odds ratio for ever-use of OCs of 2.1 (1.0-4.4). The results indicate an increased risk of premenopausal bilateral breast cancer associated with OC use.

Adult↗
PubMed1991

Heterogeneity of the effect of family history on breast cancer risk.

We studied the effects of family history on breast cancer risk among 2,908 cases and 3,180 controls, selected from participants in a nationwide screening project. First-degree family history was associated with a twofold risk increase. Second-degree family history effects were minimal, after adjusting for effects of first-degree relatives. Family history effects were not confounded by age at menarche, age at first full-term birth, age at natural menopause, or previous benign breast disease. Risks from mother's and sister's history were independent. The odds ratio (OR) from a maternal history, 1.9 (95% confidence interval [CI]: 1.6-2.3), varied little by the subject's age at diagnosis, menopause status, or disease laterality. Interactions of maternal history effects with multiple breast biopsies and age at menopause were greater than additive, indicating common mechanistic pathways. The OR from a sister's history was 2.3 (95% CI: 1.9-2.8) and was increased among women who were less than 45 (OR = 6.9), had bilateral disease (OR = 4.7), or were premenopausal (OR = 4.4). The effects from a mother's history and a sister's history are modified in different directions by different factors, providing further indication of the separate roles of a mother's and sister's history in breast cancer etiology.

Adult↗
PubMed1990

Genetic epidemiology of bilateral breast cancer: a linkage analysis using the affected-pedigree-member method.

We used the affected-pedigree-member (APM) method to conduct linkage analyses on 19 pedigrees in which the probands had premenopausal bilateral breast cancer. This method analyzes all affected pairs of relatives, as opposed to siblings only, and incorporates into the analyses information on the frequency of marker alleles. Fourteen codominant marker systems were evaluated in two separate analyses. In the first, only premenopausal cases of breast cancer were coded as affected because we assumed that postmenopausal cases were due to a different etiology. In the second analysis, all cases of breast cancer were coded as affected, irrespective of menopausal status. In the premenopausal-cases-only analysis, we observed evidence suggestive of nonindependent segregation for C3 and ESD. In the all-cases analysis, we observed much weaker evidence for C3 and ESD and noted a suggestion of nonindependent segregation for AMY2 and PGM1.

Adult↗
PubMed1989

Selection bias in case-control studies using relatives as the controls.

Investigators have suggested using relatives of cases as the control group when studying complex diseases thought to have a major genetic component. However, there is a concern about possible bias and we developed a model to examine the possibility of bias in the selection of relatives as the control group. Assuming the exposure-specific risks of disease remain constant over time, the results indicate that even when there is a correlation in the exposure status among relatives, selection of controls from relatives of cases does not, of itself, introduce bias in the estimate of effect.

Bias↗
PubMed1989

A genetic epidemiologic investigation of breast cancer in families with bilateral breast cancer. II. Linkage analysis.

We conducted genetic linkage analyses of breast cancer in 20 pedigrees, each having at least one case of bilateral breast cancer diagnosed before 50 years of age. We tested for linkage using inheritance models from previous segregation analyses, incorporating differences in risk based on menopausal status into the analyses. We tested for heterogeneity by predividing the data set based on the interval between diagnoses of the proband's two primaries (less than 1 year (synchronous) versus at least 2 years (asynchronous], and on the histological types of breast cancer in the pedigrees. Very tight linkage could be excluded between breast cancer and ABO, GC, GPT, MNS, and PGM1 for some of the different linkage analyses. A maximum lod score of +1.01 (at theta = 0.001) between ACP1 and a breast cancer susceptibility locus was seen in the asynchronous all-cases subsample.

Breast Neoplasms↗
PubMed1988

Possible heterogeneity in the segregation pattern of breast cancer in families with bilateral breast cancer.

We investigated the segregation pattern of breast cancer in families with bilateral breast cancer, classifying families with respect to menopausal status (premenopausal versus postmenopausal) and the interval between diagnosis of the two primary tumors in the probands. Probands were "synchronous" if both primaries were diagnosed within 1 year; "asynchronous" if the interval was at least 2 years. Results for four complex segregation analyses are here presented; the findings support heterogeneity in the transmission of breast cancer. In the asynchronous premenopausal-cases-only analysis, a dominant Mendelian gene can explain the breast cancer pattern. A recessive gene is sufficient to describe the breast cancer distribution in the synchronous premenopausal-cases-only analysis. The synchronous all-cases and the asynchronous all-cases analyses add postmenopausal cases of breast cancer to the premenopausal ones, considering any case to be affected. In the asynchronous all-cases analysis, neither the single-locus model nor the mixed model (that is, a major locus plus other factors, genetic and/or cultural) without generation differences in heritability can be rejected by the unrestricted mixed model with generation differences in heritability. For the synchronous all-cases analysis, a mixed model with generation differences in heritability is necessary to explain the breast cancer transmission. Potential sources of error and possible interpretations are discussed.

Breast Neoplasms↗
PubMed1988

Hormonal factors and risk of ovarian germ cell cancer in young women.

No previous controlled studies of ovarian germ cell tumours have been reported; however the tumour is similar to germ cell testicular cancer in terms of histology, age-specific incidence rates (i.e. highest rates in young adulthood), and secular trends of increasing incidence. The investigation was designed to determine if maternal hormonal factors which have been found to increase the risk of testis cancer in male offspring are also risk factors for the ovarian tumour. The analysis is based on 73 cases diagnosed before age 35 and 138 age-race matched controls. The cases were identified by tumour registries in Los Angeles (1972-84) and Seattle (1974-84) and controls were selected from friends and/or neighbourhood residents. Interviews were conducted on the telephone with mothers of cases and controls. The primary finding was that mother's use of exogenous hormones (including the hormonal pregnancy test, DES or other supportive hormones, and inadvertant use of oral contraceptives after conception) increased risk (Odds ratio, OR = 3.60, 95% CL = 1.2-13.1). Other maternal factors associated with elevated risk were high pre-pregnancy body mass (OR = 2.7, 95% CL = 1.0-7.6), more rapid achievement of regular menstruation after menarche (OR = 1.8, 95% CL = 0.9-3.8), and age at index pregnancy under 20 (OR = 2.8, 95% CL = 1.0-10.7). In conclusion, these results support findings from testis cancer studies regarding a hormonal aetiology for germ cell tumours, and a mechanism by which oestrogen may affect the germ cells is proposed.

Adolescent↗
PubMed1987

A genetic epidemiologic investigation of breast cancer in families with bilateral breast cancer. I. Segregation analysis.

A complex segregation analysis was conducted of breast cancer in 200 families with bilateral breast cancer. Results for two analyses are presented. The first analysis considered only premenopausal cases of breast cancer as affected. The results indicate that mendelian transmission of a single locus is not sufficient to explain the distribution of premenopausal breast cancer seen. A mixed model, i.e., a major locus plus other transmission (genetic and/or cultural), is necessary to explain the distribution. The second analysis added postmenopausal cases of breast cancer to the premenopausal ones, thus considering all breast cancer cases to be affected with the same disorder. The all-cases analysis is unable to reject a mixed model with no generation differences in heritability when tested against the general model, which allows for generation differences (i.e., the likelihoods for the two models were not significantly different). Approaches to studying etiologic heterogeneity in segregation analysis and results of other segregation analyses of breast cancer are presented.

Breast Neoplasms↗
PubMed1986

Correcting for variable age of onset in the estimation of familial relative risk when there is a secular trend in incidence of disease.

We discuss the effects that a secular trend in incidence would have on estimation of familial relative risk (ratio of observed to expected cumulative incidence among relatives of index cases). For example, when age-specific incidence rates of a condition have increased during the lifetimes of relatives among whom relative risk is to be estimated, familial relative risk will be biased downward if cross-sectional, age-specific incidence data are used to estimate expected cumulative incidence among relatives. The stronger the trend and the older the ages of unaffected relatives, the greater the bias will be. Incorporating different age-specific incidence curves for different birth cohorts into the analysis is an approach we suggest for correcting the bias.

Adolescent↗
PubMed1986

Identifying a limited number of foods important in supplying selected dietary nutrients.

Three methods were developed to identify a limited number of foods that are important dietary contributors of fat, dietary fiber, and vitamins A, C, and E. In the first method, foods were ranked by the amount of each nutrient supplied per person per day and the effect each food had on the relative ranking of individuals with respect to the intake of those nutrients. Foods scoring high on both scales for a given nutrient were selected as important dietary contributors of that nutrient. In the second method, foods were selected according to the mean nutrient contribution per consumer (nonconsumers of a food were eliminated from this estimation procedure). In the third method, foods were selected that contributed a relatively large percentage of the total dietary intake of a given nutrient. The three methods were applied to data from an extensive dietary questionnaire. The authors then compared the limited lists of foods identified by each method. Generally, the methods yielded similar food lists. Regression analysis was then employed to test the ability of the selected foods to predict the nutrient totals calculated from the original, more extensive dietary questionnaire. The results suggest that a limited number of foods may have strong predictive ability, but that has not been tested in any other population.

Aged↗
PubMed1985

A linkage analysis of the Gm locus and multiple sclerosis.

We conducted linkage analyses of immunoglobulin G heavy chain marker (Gm) phenotypes and multiple sclerosis (MS) in 30 families, each having at least two first-degree relatives with definite/probable MS. These families yielded positive evidence for linkage to human leukocyte antigen (HLA) loci in previous analyses. In the present analysis, however, the results for Gm were negative. Most lod scores were negative, particularly at the smaller recombination values (theta). We explored the possibility of heterogeneity by subgrouping our data on the basis of specific HLA types (A3, B7) and Gm types (Gm1, Gm1,2) within the pedigrees. The results were again negative with no substantial differences in estimates of theta between subgroups.

Gene Frequency↗
PubMed1985

Segregation and linkage analyses of 72 leprosy pedigrees.

Data on 72 families with multiple cases of leprosy were analyzed for a susceptibility gene linked to the HLA loci. We conducted segregation analysis with the program POINTER and identity of HLA types by descent analysis to determine the most likely mode of inheritance. We then conducted linkage analysis with the program LINKAS, first assuming linkage equilibrium and then allowing for linkage disequilibrium and etiological heterogeneity. Segregation results suggest a recessive mode of inheritance, especially for the tuberculoid forms of leprosy. The linkage results, limited to tuberculoid forms and assuming a recessive model, suggest a hypothesis of loose linkage with no unlinked locus. When an additive model is assumed, the best fit is obtained with a hypothesis of complete linkage (theta = 0.0) with heterogeneity. We currently favor the additive model as the more plausible one.

Disease Susceptibility↗
PubMed1983

Genetic susceptibility to multiple sclerosis: a review.

We review evidence on genetic susceptibility to multiple sclerosis provided by studies of family resemblance, migrants, twins, HLA-associations, and segregation and linkage analyses. The higher concordance rate in MZ than DZ twins and the increasing prevalence with increasing degree of kinship to propositi suggest that genetic factors are involved in the aetiology of MS. Nonetheless, the low overall twin concordance rates, the increased prevalence of MS in DZ twins over siblings, and the weight of evidence from migrant studies strongly suggest the involvement of environmental factors as well. These results can be reconciled by hypothesizing an MS susceptibility gene with reduced penetrance, where full phenotypic expression depends on critical environmental exposures. The location of this gene in or near the HLA region is suggested by the reports of HLA-MS associations and is supported by results of formal linkage analyses. Two general hypotheses have emerged. One involves loose linkage with no heterogeneity while the other involves very tight linkage and substantial heterogeneity, ie no linkage in 25% of the pedigrees. Since the MS gene is probably not a recent mutation, the hypothesis of loose linkage requires one to postulate intense selection to maintain linkage disequilibrium. It is primarily because of this intense selection that we currently favour the hypothesis of tight linkage with heterogeneity over any single-gene hypothesis involving loose linkage, given our present biological knowledge. Areas for future research are suggested.

Diseases in Twins↗