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Biomedical subjects

D Ford

Publications and source records attributed to D Ford.

At least 37 records · Page 2Linked to original sources
PubMed1996

Changing fertility patterns, 1974 to 1994.

From 1974 to 1994, the number of children Canadian women are likely to have during their lifetime decreased. This downturn in fertility meant that the annual number of live births rose only slightly during this period, even though it marked the prime childbearing years for the baby-boom generation. As they pursued higher education and employment in the paid workforce, women have postponed childbearing. Consequently, the average age of women giving birth has risen. More than a quarter of women over age 30 who have a baby are first-time mothers. And by starting families later in life, women tend to have fewer children. In addition, largely because of the growing number of common-law relationships, over a quarter of all births are to unmarried women. Using data provided by the provincial and territorial Vital Statistics Registries, this article examines national and provincial/territorial trends in births and fertility from 1974 to 1994.

Adolescent↗
PubMed1995

Risk of cutaneous melanoma associated with pigmentation characteristics and freckling: systematic overview of 10 case-control studies. The International Melanoma Analysis Group (IMAGE).

Using individual subject data from 10 case-control studies, comprising over 3000 cases and almost 4000 controls, we have estimated the relative risk of melanoma associated with aspects of complexion, namely, hair, eye and skin colour and freckling in adulthood, and have examined the relationships between these factors and naevus count in terms of melanoma risk. Compared with individuals with black or dark brown hair, the relative risks for developing melanoma in those with light brown, blonde and red hair were 1.49 (95% CI 1.31, 1.70), 1.84 (95% CI 1.54, 2.21) and 2.38 (95% CI 1.90, 2.97), respectively. Individuals with blue eyes had a risk 1.55 (95% CI 1.35, 1.78) times that for those with brown eyes, or 1.15 (95% CI 0.94, 1.40) after adjusting for hair colour and freckling in adulthood. The relative risks associated with hair and eye colour were independent of those for naevus count and skin colour. Light skin colour and high freckle density were also highly significant risk factors, independent of each other and of naevus count and hair and eye colour. The risks associated with these factors, while individually modest, are largely independent, and thus pigmentation characteristics and freckling tendency should be useful in identifying high risk groups to be targeted for prevention.

Case-Control Studies↗
PubMed1995

Risk of cutaneous melanoma associated with a family history of the disease. The International Melanoma Analysis Group (IMAGE).

In a combined analysis of 2952 melanoma patients and 3618 controls from 8 case-control studies in white populations the risk of cutaneous melanoma was 2.24-fold higher (95% CI, 1.76-2.86) in subjects who reported at least one affected first-degree relative than in subjects who did not. There was no evidence for heterogeneity in the relative risk between the studies, which were from a wide range of latitudes and hence degrees of sun exposure. The effect of family history on melanoma risk was independent of age, naevus count, hair and eye colour, and freckling. There was no evidence for a relationship between family history and primary site of melanoma but there was some suggestion that the familial patients were more likely to have superficial spreading melanoma or lentigo maligna melanoma than acral lentiginous melanoma or nodular melanoma.

Case-Control Studies↗
PubMed1995

Consistent loss of the wild type allele in breast cancers from a family linked to the BRCA2 gene on chromosome 13q12-13.

A small proportion of breast cancer is attributable to the inheritance of dominant, high penetrance susceptibility genes. One of these genes, BRCA2, has recently been localised by genetic linkage analysis to chromosome 13q12-13. This is a region known to exhibit loss of heterozygosity in 20-40% sporadic breast cancers. In this study, we have examined cancers from a family showing strong evidence of linkage to BRCA2. LOH was seen in seven out of eight informative cancers. In all cases the allele lost was the wild type allele that does not segregate with the disease in the family. The data suggest that both alleles of BRCA2 are inactivated in cancers, the pattern expected of a recessive oncogene or tumour suppressor gene.

Alleles↗
PubMed1995

Age at diagnosis as an indicator of eligibility for BRCA1 DNA testing in familial breast cancer.

We searched for criteria that could indicate breast cancer families with a high prior probability of being caused by the breast/ovarian cancer susceptibility locus BRCA1 on chromosome 17. To this end, we performed a linkage study with 59 consecutively collected Dutch breast cancer families, including 16 with at least one case of ovarian cancer. We used an intake cut-off of at least three first-degree relatives with breast and/or ovarian cancer at any age. Significant evidence for linkage was found only among the 13 breast cancer families with a mean age at diagnosis of less than 45 years. An unexpectedly low proportion of the breast-ovarian cancer families were estimated to be linked to BRCA1, which could be due to a founder effect in the Dutch population. Given the expected logistical problems in clinical management now that BRCA1 has been identified, we propose an interim period in which only families with a strong positive family history for early onset breast and/or ovarian cancer will be offered BRCA1 mutation testing.

Adult↗
PubMed1995

Filters on the pathway to mental health care, I. Incident mental disorders.

This study investigates health and mental health services use by adults with and without newly incident mental disorders and uses prospectively gathered data from the Epidemiologic Catchment Area Program, a multi-site interview survey of adult household residents in the United States. Study subjects were 13,400 participants who completed interviews in the initial survey and also in a follow-up 1 year later, and who reported no contact with mental health services in either the specialized mental health sector or in the general medical sector in the 6 months prior to the initial survey. Case ascertainment was by means of a standardized interview method, the Diagnostic Interview Schedule. Separately, and before the mental health assessments were made, respondents were asked about their use of health and mental health services. 'Hierarchical' and 'filter' models of mental health services provide frameworks useful in understanding the possible effects of specific categories of psychiatric disturbances on use of health services. Only a minority of individuals with newly incident psychiatric disorder report discussion of mental health issues in a health care setting. Persons who developed a mental disorder during the follow-up interval were just as likely to consult a non-psychiatrist physician for their mental health problems as to consult a specialist in mental health, even accounting for other factors known to be associated with differential use of health care services. This large community study of incident psychiatric disorders strengthens prior evidence on the importance of the general medical sector in the care of individuals with psychiatric disturbances.

Adolescent↗
PubMed1995

Filters on the pathway to mental health care, II. Sociodemographic factors.

This study uses the prospectively gathered data of the Epidemiologic Catchment Area Program, a multi-site interview survey of mental disturbances among adult household residents in the United States, to compare health services use by individuals with different sociodemographic characteristics, accounting for the first-time occurrence of psychiatric disorder, over the course of a 1-year follow-up interval. Case ascertainment was by means of a standardized interview method, the Diagnostic Interview Schedule. In the present investigation, 13,400 continuing participants in the household sample who reported no contact with mental health services in the 6 months prior to the initial interview were studied with regard to health services use and sociodemographic characteristics. Separately, and before the mental health assessments were made, respondents were asked about their use of health and mental health services. African-Americans were significantly less likely than whites to have consulted with a specialist in mental health (estimated relative odds, 0.22, 95% confidence interval 0.10 to 0.52), even accounting for coincident psychiatric disorder, gender, and other covariates known to be associated with differential use of health care services. Hispanics and other minorities were also less likely to have consulted a specialist in mental health (estimated relative odds, 0.37 and 0.26, respectively). This large community study extends previous work on mental health services and ethnicity.

Adult↗
PubMed1995

The genetics of breast and ovarian cancer.

A number of genes are known to be involved in inherited susceptibility to breast and/or ovarian cancer. In the context of high-risk families the most important genes are BRCA1 on chromosome 17q, which is associated with a high penetrance of both breast and ovarian cancer, and BRCA2 on chromosome 13q, which causes a high risk of breast cancer but a lower risk of ovarian cancer. Other high-risk cancer genes that confer increased risks of breast or ovarian cancer in addition to other cancers include the hereditary non-polyposis colorectal cancer genes and the TP53 gene, which causes breast cancer as part of the Li-Fraumeni syndrome. The predisposing mutations in these genes are relatively rare in the population. More common genes which are associated with an increased, but lower, risk of breast cancer are the ataxiatelangiectasia gene and the HRAS1 gene. This paper reviews recent progress in mapping and cloning of these susceptibility genes, and provides estimates of the cancer risks associated with each gene and the frequency of predisposing mutations.

Ataxia Telangiectasia↗
PubMed1995

Localisation of the Fanconi anaemia complementation group A gene to chromosome 16q24.3.

Fanconi anaemia (FA) is an autosomal recessive disorder associated with diverse developmental abnormalities, bone-marrow failure and predisposition to cancer. FA cells show increased chromosome breakage and hypersensitivity to DNA cross-linking agents such as diepoxybutane and mitomycin C. Somatic-cell hybridisation analysis of FA cell lines has demonstrated the existence of at least five complementation groups (FA-A to FA-E), the most common of which is FA-A. This genetic heterogeneity has been a major obstacle to the positional cloning of FA genes by classical linkage analysis. The FAC gene was cloned by functional complementation, and localised to chromosome 9q22.3 (ref. 2), but this approach has thus far failed to yield the genes for the other complementation groups. We have established a panel of families classified as FA-A by complementation analysis, and used them to search for the FAA gene by linkage analysis. We excluded the previous assignment by linkage of an FA gene to chromosome 20q, and obtained conclusive evidence for linkage of FAA to microsatellite markers on chromosome 16q24.3. Strong evidence of allelic association with the disease was detected with the marker D16S303 in the Afrikaner population of South Africa, indicating the presence of a founder effect.

Chromosome Mapping↗
PubMed1995

Familial cylindromatosis (turban tumour syndrome) gene localised to chromosome 16q12-q13: evidence for its role as a tumour suppressor gene.

The human skin is a complex organ composed of the surface epidermis, the subjacent dermis (in which blood vessels, lymphatics and nerves are located) and the skin appendages. The latter include hair follicles, sebaceous glands (which secrete lipids that may serve as a permeability barrier, emollient or antimicrobial agent), apocrine glands (which secrete scents) and eccrine glands (which produce sweat for temperature control). Hereditary cylindromatosis (MIM 123850) is a rare autosomal dominant disease characterised by the development of multiple neoplasms originating from the skin appendages. These neoplasms have been termed cylindromas due to their characteristic microscopic architecture and are believed to exhibit apocrine or eccrine differentiation. We have carried out a genome search using two families with this disease, which has provided strong evidence for linkage of cylindromatosis to loci on chromosome 16q12-q13. Using markers close to the cylindromatosis gene, consistent loss of the wild-type allele was observed in 19 tumours from four individuals in the two families, indicating that the gene is likely to be a tumour suppressor gene.

Carcinoma, Adenoid Cystic↗
PubMed1995

Recovery of human immunodeficiency virus from peritoneal dialysis effluent.

Increasing numbers of HIV-infected patients who have ESRD are being treated with continuous ambulatory peritoneal dialysis (CAPD). To investigate the potential infectious nature of peritoneal dialysate (PD), the peritoneal dialysis effluent was studied in 14 patients on CAPD who were known to be HIV antibody positive. Peripheral blood mononuclear cells and the sediment of PD were obtained from each patient and subjected to a qualitative microculture assay using a coculture of patient cells or PD fluid with peripheral blood mononuclear cells from non-HIV-infected individuals. Samples from the coculture were collected twice weekly for HIV P24 antigen determination as a marker of viral replication. PD, white blood cell and red blood cell counts, and peripheral blood CD4 lymphocyte counts were also measured. All 14 patients developed a positive blood culture by Day 3. Twelve of the 14 patients developed a positive PD fluid culture. The mean CD4 count was 310 cells/mm3. No patient had clinical or cellular evidence of peritonitis at the time of fluid sampling. These data indicate that peritoneal dialysis effluent from patients who are HIV antibody positive is potentially infectious.

Adult↗
PubMed1995

An evaluation of genetic heterogeneity in 145 breast-ovarian cancer families. Breast Cancer Linkage Consortium.

The breast-ovary cancer-family syndrome is a dominant predisposition to cancer of the breast and ovaries which has been mapped to chromosome region 17q12-q21. The majority, but not all, of breast-ovary cancer families show linkage to this susceptibility locus, designated BRCA1. We report here the results of a linkage analysis of 145 families with both breast and ovarian cancer. These families contain either a total of three or more cases of early-onset (before age 60 years) breast cancer or ovarian cancer. All families contained at least one case of ovarian cancer. Overall, an estimated 76% of the 145 families are linked to the BRCA1 locus. None of the 13 families with cases of male breast cancer appear to be linked, but it is estimated that 92% (95% confidence interval 76%-100%) of families with no male breast cancer and with two or more ovarian cancers are linked to BRCA1. These data suggest that the breast-ovarian cancer-family syndrome is genetically heterogeneous. However, the large majority of families with early-onset breast cancer and with two or more cases of ovarian cancer are likely to be due to BRCA1 mutations.

Adult↗
PubMed1995

Breast and ovarian cancer incidence in BRCA1-mutation carriers. Breast Cancer Linkage Consortium.

Dominant predisposition to early-onset breast cancer and/or ovarian cancer in many families is known to be the result of germ-line mutations in a gene on chromosome 17q, known as BRCA1. In this paper we use data from families with evidence of linkage to BRCA1 to estimate the age-specific risks of breast and ovarian cancer in BRCA1-mutation carriers and to examine the variation in risk between and within families. Under the assumption of no heterogeneity of risk between families, BRCA1 is estimated to confer a breast cancer risk of 54% by age 60 years (95% confidence interval [CI] 27%-71%) and an ovarian cancer risk of 30% by age 60 years (95% CI 8%-47%). Similar lifetime-risk estimates are obtained by examining the risks of contralateral breast cancer and of ovarian cancer, in breast cancer cases in linked families. However, there is significant evidence of heterogeneity of risk between families; a much better fit to the data is obtained by assuming two BRCA1 alleles, one conferring a breast cancer risk of 62% and an ovarian cancer risk of 11% by age 60 years, the other conferring a breast cancer risk of 39% and an ovarian cancer risk of 42%, with the first allele representing 71% of all mutations (95% CI 55%-87%). There is no evidence of clustering of breast and ovarian cancer cases within families.

Adult↗
PubMed1995

Estimates of the gene frequency of BRCA1 and its contribution to breast and ovarian cancer incidence.

The majority of multiple-case families that segregate both breast and ovarian cancer in a dominant fashion are due to mutations in the BRCA1 gene on chromosome 17q. In this paper, we have combined penetrance estimates for BRCA1 with the results of two population-based genetic epidemiological studies to estimate the gene frequency of BRCA1. On the assumption that the excess risk of ovarian cancer in first degree relatives of breast cancer patients and the breast cancer excess in relatives of ovarian cancer patients are both entirely accounted for by BRCA1, we estimate that the BRCA1 gene frequency is 0.0006 (95% confidence interval [O.002-0.002]) and that the proportion of breast cancer cases in the general population due to BRCA1 is 5.3% below age 40 years, 2.2% between ages 40 and 49 years, and 1.1% between ages 50 and 70 years. The corresponding estimates for ovarian cancer are 5.7%, 4.6%, and 2.1%, respectively. Our results suggest that the majority of breast cancer families with less than four cases and no ovarian cancer are not due to rare highly penetrant genes such as BRCA1 but are more likely to be due either to chance or to more common genes of lower penetrance.

Adult↗
PubMed1994

Localization of a breast cancer susceptibility gene, BRCA2, to chromosome 13q12-13.

A small proportion of breast cancer, in particular those cases arising at a young age, is due to the inheritance of dominant susceptibility genes conferring a high risk of the disease. A genomic linkage search was performed with 15 high-risk breast cancer families that were unlinked to the BRCA1 locus on chromosome 17q21. This analysis localized a second breast cancer susceptibility locus, BRCA2, to a 6-centimorgan interval on chromosome 13q12-13. Preliminary evidence suggests that BRCA2 confers a high risk of breast cancer but, unlike BRCA1, does not confer a substantially elevated risk of ovarian cancer.

Breast Neoplasms↗