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Biomedical subjects

A D Sadovnick

Publications and source records attributed to A D Sadovnick.

At least 109 records · Page 6Linked to original sources
PubMed1988

Life expectancy in Down syndrome adults.

Life expectancy for adults with Down syndrome was calculated from data for 1610 liveborn affected individuals identified in over 1,500,000 consecutive live births in British Columbia from 1908 to 1981. Survival to 68 years of age, predicted from the available data, is better than in previous estimates, but is still much poorer than for the general population: about 44.4% and 13.6% of liveborn Down syndrome individuals will survive to 60 and 68 years, respectively, compared with 86.4% and 78.4% of the general population.

Actuarial Analysis↗
PubMed1988

Multiple sclerosis: updated risks for relatives.

Two important characteristics of multiple sclerosis (MS) are familial clustering and a variable age of onset. There is increasing evidence for a genetically influenced susceptibility in MS. Because of this, patients and their relatives are increasingly asking about the risk for relatives of developing MS. In the MS Clinic in Vancouver, genetic histories are taken routinely for all patients and are updated annually. Patients do not attend the clinic specifically to participate in genetic studies, which could result in over-representation of familial cases. Data were available for 815 MS index cases and 11,345 of their relatives. Age-specific MS risks were calculated for first-, second-, and third-degree relatives of probands and are presented in an easy-reference format. In general, first-degree relatives of probands have a risk that is 30-50 times greater than the 0.1% risk for the general population.

British Columbia↗
PubMed1988

Maternal age-specific rates for Down syndrome: changes over time.

There have been conflicting reports about whether incidence rates at given maternal ages for Down syndrome (DS) are changing over time. British Columbia provides an excellent opportunity to look at this question as there is 1) nearly complete ascertainment of DS livebirths, 2) a relatively large number of annual births, 3) data on a 20-year time period, 4) data on age-specific fertility rates over this period, and 5) cytogenetic data on all pregnancies terminated through the provincial prenatal diagnosis program since its inception. Data on 856 liveborn DS infants over a 20-year period (1964-1983) were analyzed. Controlling for maternal ages, the data were examined for transient changes in incidence over time and for linear and cyclic trends. No significant (P greater than 0.05) changes in DS incidence were observed over this 20-year period in any maternal age group.

Adolescent↗
PubMed1988

Familial Alzheimer's disease.

A family with familial Alzheimer's disease (FAD) inherited as an apparent autosomal dominant trait is presented. Twelve individuals (6 females; 6 males) in 4 generations were affected. The disease had its onset in the late 30's, early 40's with death by age 50. Although FAD which appears to be transmitted as an autosomal dominant trait is relatively rare, such families must be identified and carefully counselled with respect to recurrence risks for subsequent generations. In this family, there are currently 20 members of Generation IV, aged 15-37, and 9 members of Generation V, aged 1-11. The majority of these individuals appear to have a 50% risk for developing this disease.

Adult↗
PubMed1988

The familial nature of multiple sclerosis: age-corrected empiric recurrence risks for children and siblings of patients.

Increasingly, MS patients ask neurologists about the risk that their close relatives will also develop MS. We calculated age-adjusted empiric recurrence risks from data on 815 index cases and over 3,000 of their siblings and children. In general, the risk for these relatives to develop MS is 3 to 5%, which is 30 to 50 times the 0.1% rate for the general population.

Age Factors↗
PubMed1988

Causes of death to age 30 in Down syndrome.

To look at the underlying cause of death (U.C.O.D.) data for Down syndrome (DS), we studied 324 DS individuals who died out of a total of 1,337 DS births occurring in 1,066,508 consecutive live births during the years 1952-81 inclusive. U.C.O.D. rates, separated into ICD-9 classifications, for the DS population were compared with those of the age-matched general population. In general, an individual with DS is significantly more likely to die than the age-matched general population over all ages studied up to age 30. The greatest absolute likelihood of dying is under 1 year, but the age group with the greatest relative risk of dying (17.2) is very definitely between ages 1-9. In order, the three categories for causes of death in DS with the greatest relative risk are congenital anomalies, circulatory system, and respiratory system.

Accidents↗
PubMed1987

Use of genetic counselling services for neural tube defects.

Genetic counselling is recommended for parents of children with neural tube defects (NTDs) to inform them of the recurrence risks and the option of prenatal diagnosis. British Columbia provides an excellent site to examine the use by parents of genetic counselling services for NTDs. Genetic services for the entire province are centralized, and there is virtually complete ascertainment of all NTD births. The results from this study indicate that use of genetic counselling services is influenced by the type of NTD present and whether the index case was live or stillborn. Genetic counselling is most often sought after the birth of a liveborn infant with spina bifida.

Anencephaly↗
PubMed1987

A comparison of incidence trends for esophageal atresia and tracheoesophageal fistula, and infectious disease.

There has been a suggestion that esophageal atresia with tracheoesophageal fistula (EA/TEF) may be related to the occurrence of infectious disease in the population during the time of early gestation. There is therefore a need for further data on trends in incidence related to infectious diseases. Data on the occurrence of EA/TEF with and without additional congenital malformations may also be relevant. The British Columbia Health Surveillance Registry is population-based with excellent case ascertainment of birth defects, and data are available on the incidence of infectious diseases for B.C., allowing comparison of trends to be made. One hundred forty-nine cases of EA/TEF occurred among 534,834 consecutive livebirths during the period 1966-1980 for an incidence rate of 1/3,590. No significant (p less than 0.05) annual, seasonal or monthly incidence trends were observed. In addition, the occurrence of EA/TEF could not be correlated with the prior incidence of infectious hepatitis, rubella, salmonella, or rubeola. Fifty-five percent of individuals with EA/TEF had congenital malformations in other systems, most frequently cardiovascular, gastrointestinal, and genitourinary. Most individuals with additional congenital malformations had multiple system involvement.

British Columbia↗
PubMed1987

Life expectancy in Down syndrome.

This study is part of a collaborative effort between the Division of Vital Statistics, Ministry of Health, Province of British Columbia and the Department of Medical Genetics, University of British Columbia. Permission to use the provincial vital and health records was conditional on the strict observance of the oath of secrecy regarding the nonstatistical information contained in the records. To develop life expectancy data for Down syndrome, we studied 1341 patients with Down syndrome identified by the British Columbia Health Surveillance Registry from more than one million consecutive live births from 1952-1981 inclusive. Our results indicate that life expectancy is much better than generally believed. For patients with Down syndrome with congenital heart anomalies, survival to age 1 year is 76.3%; to age 5, 61.8%; to age 10, 57.1%; to age 20, 53.1%; and to age 30, 49.9%. For patients with Down syndrome without congenital heart anomalies, survival to the same ages is 90.7%; 87.2%, 84.9%, 81.9%, and 79.2%, respectively. Survival for these patients without congenital heart defects is still significantly lower than that for a comparison group of mentally retarded persons without congenital heart defects.

Actuarial Analysis↗
PubMed1986

A population-based study of multiple sclerosis in twins.

Results from studies of twin concordance in multiple sclerosis have not conclusively differentiated between environmental and genetic factors that determine susceptibility to the disease. Published studies that have been based on case finding by public appeal have been characterized by difficulties in ascertainment. The data reported here are from a large population-based study of multiple sclerosis in twins, in which ascertainment has been relatively unbiased and the cooperation of patients nearly complete. A total of 5463 patients attending 10 multiple sclerosis clinics across Canada were surveyed. Twenty-seven monozygotic and 43 dizygotic twin pairs were identified, and the diagnosis of multiple sclerosis was verified by examination and laboratory investigation. Seven of 27 monozygotic pairs (25.9 percent) and 1 of 43 dizygotic pairs (2.3 percent) were concordant for multiple sclerosis. The concordance rate for 4582 nontwin siblings of patients at two multiple sclerosis clinics was 1.9 percent, closely paralleling the concordance rate in dizygotic twins. To the extent that the difference in concordance rates between monozygotic and dizygotic twins indicates genetic susceptibility, the results of this study show a major genetic component in susceptibility to multiple sclerosis.

Canada↗
PubMed1986

Risks to sibs of probands with neural tube defects: data for clinic populations in British Columbia.

The purpose of this study is to determine whether couples receiving genetic counselling because of a child with a neural tube defect (NTD) are a selected group and therefore not representative of the general population with respect to sib risks for NTDs. British Columbia (B.C.) provides an excellent opportunity to look at this for several reasons. Firstly, genetic counselling services are centralized. Secondly, there is virtually complete ascertainment of all infants with NTDs in the province. Thirdly, sib risks for NTDs in the general population have been derived previously [McBride, 1979] and, therefore, are available for comparison with the risks for sibships in the clinic populations. In the present study, data were available on 398 sibships in which the index case had anencephaly and/or spina bifida. In all instances, sib risks for the clinic populations did not differ significantly from those for the general population. In addition, congenital malformations other than NTDs did not occur among sibs of index cases more often than expected, based on provincial incidence data.

Anencephaly↗
PubMed1986

Prevalence of multiple sclerosis in British Columbia.

A province wide prevalence study on multiple sclerosis (MS) was conducted in British Columbia (B.C.). The prevalence date was July 1, 1982. The major portion of this study was a review of all the files of neurologists practicing in B.C. as this was judged to be the most accurate source for identifying MS patients. 239,412 neurologists' files were hand searched by one researcher using modified Schumacher criteria for classification. Other sources used during the study for identifying MS patients were the MS Clinic, general practitioners, ophthalmologists, urologists, specialized facilities such as long term care facilities and rehabilitation centres, and patient self-referrals. A total of 4,620 non-duplicated cases were identified and classified. 4,112 of these (89%) were classified according to information contained in neurologists' records. The prevalence estimate for definite/probable MS in B.C. was 93.3/100,000 population. This increased to 130.5/100,000 population if possible MS and optic neuritis were also included. These rates are among the highest reported in Canada or elsewhere. The cooperation of B.C. neurologists made this study unique in its scope and accuracy of diagnosis.

Adolescent↗
PubMed1986

Fetal mortality in sibships of cases with neural tube defects.

Rates of fetal mortality in sibships of probands with neural tube defects (NTDs) may reflect liability to NTDs. Expectations from the multifactorial model predict that fetal loss should be higher in sibships of male probands; in multiplex sibships; and sibships where the proband had no additional malformations. This was analysed for 715 pregnancies from 398 sibships. In general, the results did not support the expectations of the multifactorial model.

Abortion, Spontaneous↗