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Biomedical subjects

I M Yee

Publications and source records attributed to I M Yee.

14 recordsLinked to original sources
PubMed1998

Effect of age at onset and parental disease status on sibling risks for MS.

MS is believed to be a complex trait determined by genetic and nongenetic factors. Data suggest that MS susceptibility and age at onset are each, at least to some extent, under genetic control. The present study carefully examined five covariates (sex of the index case, sex of the sibling, birth cohort of the sibling [< or = 1919, 1920 to 1939, > or = 1940], age of MS onset in the index patient (< or = 20 years, 21 to 30 years, 31 to 40 years, > 40 years), and MS disease status of the parents [i.e., MS present in one parent or no parent with MS]) that may influence the familial risk of MS in a large cohort of 1,896 MS patients and 8,878 of their first-degree relatives. Of these, sex of the sibling, parental MS status, and index patient onset age were the important factors influencing MS risks to siblings. The results of this study are (1) the index-patient-onset-age effect suggests that individuals with a greater genetic loading (i.e., a greater contribution of susceptibility alleles) have an earlier age at onset and (2) genetic loading is substantially increased in individuals with an affected parent. These data are important both for genetic counseling and gene identification studies.

Adult↗
PubMed1997

Risks of multiple sclerosis in relatives of patients in Flanders, Belgium.

OBJECTIVES: To calculate age adjusted risks for multiple sclerosis in relatives of Flemish patients with multiple sclerosis. METHODS: Lifetime risks were calculated using the maximum likelihood approach. RESULTS: Vital information was obtained on 674 probands with multiple sclerosis in Flanders and a total of their 26225 first, second, and third degree relatives. Full medical information to allow documentation of multiple sclerosis status was available for 21351 (81.4%) relatives. The age adjusted risk for parents was 1.61 (SEM 0.35)%, for siblings 2.10 (SE 0.36)%, and for children 1.71 (SEM 0.70)%. For aunts and uncles, the risk was 0.66 (SEM 0.13)%. CONCLUSIONS: The risk for first degree relatives of patients with multiple sclerosis in Flanders is increased 10-fold to 12-fold; for second degree relatives, it is increased threefold. This information can be used for risk counselling in families and provides additional support for the role of more than one locus contributing to the susceptibility of multiple sclerosis.

Adult↗
PubMed1996

Major depression, minor depression, and double depression: are they distinct clinical entities?

The clinical concept of "double depression," i.e., the superimposition of a major depressive disorder in a patient with dysthymic disorder, implies that there are at least some differences between dysthymia, major depression, and double depression. However, the relationship between these two syndromes remains unclear. The present study uses genetic methodology to explore any possible relationship between minor depression, double depression, and major depression. From 1988-1990, all consecutive unrelated inpatients and outpatients (index cases) presenting to a university-based mood disorders service had detailed family histories taken, using modification of the "family history method." Diagnoses for index cases and their first-degree relatives were made according to Research Diagnostic Criteria. For all index cases with a diagnosis of minor or intermittent depression, and minor/intermittent depression plus either single or recurrent depression ("double depression"), morbidity risks for mood disorders were calculated for first-degree relatives (parents, siblings, and children) using the maximum likelihood approach. Results showed no significant differences in morbidity risk calculations to first-degree relatives of index cases with minor/intermittent depression, major depression, or double depression. The data from this genetic perspective suggest that single depression, recurrent depression, minor depression, and double depression are indistinguishable.

Depression↗
PubMed1996

Depression and multiple sclerosis.

The objective of the present study were (1) to ascertain the lifetime risk of a depression in a representative group of multiple sclerosis (MS) patients, (2) to assess the morbidity risks for depression among first-degree relatives of these MS patients, and (3) to compare these familial risks for first-degree relatives of MS patients with those for first-degree relatives of a primary depression population, i.e., depression but no MS. We psychiatrically evaluated 221 MS patients (index cases) using a structured clinical interview for the DSM-III-R and calculated the rate and lifetime risk of depression for these index cases using the product limit estimate of survival function. We obtained psychiatric histories for all first-degree relatives of index cases, and we calculated morbidity risks for depression for these relatives using the maximum likelihood approach and compared the risks using the likelihood ratio tests. Index cases had a 50.3% lifetime risk of depression. Morbidity risks for depression among first-degree relatives of index cases were decidedly lower when compared with morbidity risks among first-degree relatives of the reference population. Although there appears to be a very high rate of depression among MS patients, the data for their first-degree relatives do not support a clear genetic basis for this depression, or at least the same genetic basis that probably operates within families when depression occurs in the absence of MS.

Adolescent↗
PubMed1995

Sibling risks of abdominal aortic aneurysm.

There is evidence that the risk of abdominal aortic aneurysm (AAA) is greater in first-degree relatives of patients with the disorder than in the same age group of the general population. We conducted a 3-year study of siblings of AAA probands and siblings of a control group (cataract surgery patients) of the same age. Genetic information was obtained by interview from 126 probands and 100 controls; another family member was present at the interview. Medical records were obtained and further information verified before a sibling (over age 50) was assigned affected status. Of 427 siblings of probands, 19 (4.4%) had probable or definite AAA, compared with five (1.1%) of 451 siblings of controls. The lifetime cumulative risks of AAA at age 83 were 11.7% (SD 3.1) and 7.5% (4.1), respectively. The risk of AAA began at an earlier age and increased more rapidly for probands' siblings than for controls' siblings (p < 0.01, log-rank test). A risk comparison, based on the results of ultrasound screening of 54 geographically accessible siblings of probands and the 100 controls showed a similar pattern. Ten (19%) siblings of probands and eight (8%) controls had AAA on ultrasound (lifetime cumulative risk 60.8% [18.9] vs 14.9% [5.1], p = 0.01). These results show that familial factors influence the age of onset of AAA. We recommend routine ultrasound examination of siblings of patients with AAA.

Age Factors↗
PubMed1994

Population-based study of long-term outcomes after amniocentesis.

Amniocentesis is now commonly used in many countries; it is important to know whether there are any long-term adverse effects on children born after this procedure, in particular disabilities that may emerge during childhood or adolescence. We studied consecutive liveborn offspring of women who had had amniocentesis and compared them with matched controls whose mothers had not had amniocentesis. The controls were matched for age of mother, residence by geographic health unit, sex, and when the birth occurred. 1296 cases and 3704 controls were studied. With the exception of one disorder, the offspring of women who had had amniocentesis were no more likely than controls to have a registrable disability (such as hearing disabilities, learning difficulties, visual problems, and limb anomalies) during childhood and adolescence. The follow-up period was 7-18 years. Children of women who had amniocentesis had a significantly higher rate of haemolytic disease due to ABO isoimmunisation than matched controls. The results of this study should therefore be reassuring to women having amniocentesis, and be useful to women making decisions about having this procedure.

Adolescent↗
PubMed1994

Mood Disorder Service Genetic Database: morbidity risks for mood disorders in 3,942 first-degree relatives of 671 index cases with single depression, recurrent depression, bipolar I, or bipolar II.

There is increasing evidence that genetic factors play a role in the etiology of mood disorders. As a result, relatives of affected individuals are more often asking about their own risks to develop a mood disorder. From 1988 to 1990, all consecutive, unrelated inpatients and outpatients (index cases) presenting to the Mood Disorders Service, Department of Psychiatry, University of British Columbia, had detailed family histories taken, thus creating the Mood Disorders Service Genetic Database. Diagnoses for index cases and their first-degree relatives were made according to Research Diagnostic Criteria and Family History Research Diagnostic Criteria respectively. Morbidity risks for mood disorders were calculated for first-degree relatives (parents, siblings, children--aged 10 and above) of all index cases with a diagnosis of single depression, recurrent depression, bipolar I, or bipolar II disorder. Morbidity risks were calculated using the maximum likelihood approach. Morbidity risk data are presented according to the sex and diagnosis for the index case in an easy reference format for risk counselling. The risks are presented twice, including and excluding data for "high-risk" families whose genetic pedigree is suggestive of "autosomal dominant" inheritance.

Age of Onset↗
PubMed1994

Pregnancy and multiple sclerosis. A prospective study.

OBJECTIVE: To conduct a prospective assessment of pregnancy on women with multiple sclerosis (MS), focusing on pregnancy outcome and relapses during gestation and up to 6 months after delivery. DESIGN: Expected numbers of relapses were based on data for (1) "self-controls": the mothers ("cases") themselves prior to becoming pregnant and (2) "matched controls": female patients with MS "matched" to the mothers for year of birth, age of MS onset, MS type, MS course, and initial MS symptom(s). SETTING: Cases and controls were identified from an ambulatory care MS clinic that serves the province of British Columbia, Canada. PATIENTS OR OTHER PARTICIPANTS: Women with a diagnosis of MS who attended the MS clinic during 1982 through 1986 and subsequently became pregnant during 1982 through 1989 inclusive were included in this study as cases. Matched controls were women with MS who attended the MS clinic during the same period but did not become pregnant. RESULTS: No significant increase in relapse rate was found for cases during the first two trimesters of gestation. The number of relapses was significantly less than expected during the third trimester compared with matched controls (chi 2 = 6.80, df = 1, P < .02), but not compared with self-controls (chi 2 = 3.39, df = 1, P > .05). The observed number of relapses for the 6 months after delivery did not differ significantly from expected (self-controls: chi 2 = 2.84, df = 2, P > .05; matched controls: chi 2 = 1.76, df = 2, P > .05). CONCLUSION: These data suggest that neither pregnancy nor the 6-month period after delivery is a risk factor for relapse in MS. They are consistent with previous observations that, in the long term, pregnancy does not influence subsequent MS disability.

Female↗
PubMed1994

Familial risks for Alzheimer disease from a population-based series.

Kaplan-Meier risks estimates are calculated and compared for two consecutive series (N1 = 840, N2 = 819) of first-degree relatives of Alzheimer disease (AD) patients diagnosed as either "probable" or "autopsy-confirmed" AD. The consistency of results increases confidence in estimates and suggests consistent case ascertainment over 8 years. Lifetime risk estimates to age 88 for the combined sample (23.4% +/- 3.0%) do not approach the 50% risk compatible with an autosomal dominant model of transmission. These results support our previous finding and suggest that an autosomal dominant gene(s) is not responsible for all cases of AD.

Aged↗
PubMed1994

Maternal age and oral cleft malformations: data from a population-based series of 576,815 consecutive livebirths.

It has been suggested that older mothers are more likely to have a child with isolated cleft palate (CP) or cleft lip +/- cleft palate (CL +/- CP), but most of these studies have been based on fairly small sample sizes. Data from a population-based registry with multiple sources of case ascertainment were used to examine any association of maternal age with the incidence of these defects in infants without other congenital anomalies. The study group consisted of all cases with CP or CL +/- CP without other congenital anomalies from a series of over half a million consecutive livebirths during the period 1966 to 1981 inclusive in British Columbia. During the study period, the overall incidences of isolated CP and isolated CL +/- CP per 10,000 livebirths were 3.9 and 8.2, respectively. No association with maternal age was found when either isolated CP or isolated CL +/- CP was analyzed as a group. When analyzed by sex, and by CP or CL +/- CP, no significant maternal-age effect was observed for males and females with CP or CL +/- CP. Our population-based data, therefore, do not show that older mothers are more likely to have a child with cleft palate, or cleft lip +/- cleft palate.

British Columbia↗
PubMed1994

The rate of the Down syndrome among offspring of women with Alzheimer disease.

It has been reported that the Down syndrome occurs more often than expected among relatives of individuals with Alzheimer disease. This study focused on 578 liveborn offspring of 206 females with Alzheimer disease. Controlling for maternal age at delivery, the frequency of the Down syndrome live births was as expected, based on data for the well-monitored general population of British Columbia (chi 2 = 5.39; df = 3; p > 0.05).

Adolescent↗
PubMed1994

Season of birth in multiple sclerosis.

The monthly distribution of births of people who were later diagnosed with multiple sclerosis (MS) did not differ significantly from that of the general population in British Columbia, Canada. This is in contrast to a recent report on the Danish population.

Adolescent↗
PubMed1991

Maternal age and birth defects: a population study.

Since more and more women in developed countries are delaying childbearing to an older age, it is important to find out whether birth defects, other than those resulting from chromosomal anomalies, are related to maternal age. We have studied all 26,859 children with birth defects of unknown aetiology identified among 576,815 consecutive livebirths in British Columbia. All these cases' records were linked with provincial birth records to allow determination of maternal age at birth. We excluded children with chromosomal anomalies and those with other birth defects of known aetiology. Only 3 of the 43 birth defect categories studied showed significant maternal-age-specific trends: there were decreasing linear trends with maternal age for patent ductus arteriosus (chi 2 = 36.65, 1 df, p less than 0.01) and hypertrophic pyloric stenosis (chi 2 = 4.90, 1 df, p less than 0.05) and a bell-shaped curve (risk increasing to maternal age 30 then falling) for congenital dislocatable hip/hip click. The findings from this population-based analysis of no association between the incidence of birth defects of unknown aetiology and advancing maternal age should be reassuring to healthy women who opt to delay childbearing.

Abnormalities, Multiple↗