Biomedical subjects

B Floderus-Myrhed

Publications and source records attributed to B Floderus-Myrhed.

8 recordsLinked to original sources

PubMed1984

Familial factors in mortality with control of epidemiological covariables. Swedish twins born 1886-1925.

A Cox proportional hazard regression analysis was carried out that evaluated age-specific death risk among 21,890 twins born in Sweden during 1886 through 1925 and followed during 1962 through 1980. Cotwin's survival was used as the primary covariable, and auxiliary covariables were smoking, marital status and, among men, police registration for alcohol abuse. In each age, sex and zygosity group, except the oldest DZ males, cotwin's mortality had a significant, independent, positive relationship to the mortality risk of the individual. The auxiliary covariables, except marital status among females, had significant, independent, positive relationships to mortality among the youngest twins of both zygosity groups and in the middle age group of MZ twins. In the oldest age group, the death of MZ cotwins was the only variable significantly related to the individual's mortality. Heritability estimates for the age-specific probability or death risk, developed by different methods for different analysis groups, range between 0.4 and 0.6. They have reasonable internal consistency, are not much affected by the covariates, and are in agreement with other studies that did not control covariates.

Aged↗

PubMed1984

Twin analysis as a potential tool for examining psychosocial factors associated with and preceeding smoking behaviors.

Data from the young cohort of the Swedish Twin Registry are being used in an attempt to describe characteristics which distinguish among current, non- and ex-smokers prior to the development of a smoking habit versus those present after establishment of the habit (or lack of one). With twins as a sample of individuals, the psychosocial variables instability, extroversion, leisure activity, relative weight, alcohol, coffee and psychopharmaceutic drug use were examined jointly as predictors of current smoking status in multiple regression analyses. This phase was intended to replicate and expand upon earlier studies characterizing current, non- and ex-smokers. These analyses were then performed on MZ nonsmoking twin individuals who were classified on the basis of their cotwins' smoking status. Pattern of variation in the psychosocial variables across the groups of nonsmokers were similar to the pattern seen for current, ex- and nonsmokers. Characteristics in MZ nonsmokers which are predictive of their cotwins' smoking status may be interpreted as those present prior to development of a smoking habit. Selected results from these analyses will be presented.

Adult↗

PubMed1984

Swedish early separated twins: identification and characterization.

A sample of twins separated early in life has been identified in the Swedish Twin Registry. When the registry was compiled in 1961 (old cohort) and 1973 (young cohort), one or both members of 961 pairs indicated that they were separated by the age of 10. In May 1979, both members of 698 pairs were alive and were sent a questionnaire concerning the circumstances of separation. Items included reasons and timing of separation, biological relatedness of rearing parents, degree of contact after separation (including whether they lived in the same area, attended the same school, or lived together again), rough measures of selective placement, and current frequency of contact. An attempt was then made to categorize the pairs based on degree of separation. A total of 257 pairs met the criteria: rearing parents of one twin biologically unrelated to rearing parents of the cotwin, twins not living together again after separation, and contact after separation a few times a year or less. As much as 50% were separated by their first birthday, and 80% by the age of five. Various data from the twin registry are presented describing the entire sample of early separated twins as compared to a matched sample of twins reared together.

Adolescent↗

PubMed1983

Co-twin control study of the relationship between smoking and some periodontal disease factors.

The study was based on 164 twin pairs from the older cohort of the Swedish twin registry. The main purpose of the study was to analyze previously recorded data concerning gingival bleeding in members of twin pairs with differing smoking exposure. Other periodontal disease factors analyzed were plaque index, alveolar bone index and tooth loss. It was found that the degree of alveolar bone loss and the number of teeth lost were greater in twins with a high life-time smoking exposure than in their twin partners with a low life-time exposure. Contrary to expectation, it was found that gingival bleeding propensity was less prevalent in the high exposure group. It is concluded that the validity of gingival bleeding as a sign and a symptom of inflammatory periodontal disease may be reduced as a consequence of smoking.

Adult↗

PubMed1982

Cigarette smoking and alcohol use in Finland and Sweden: a cross-national twin study.

Cigarette smoking and alcohol use habits in Finland and Sweden were studied using data from the Finnish and Swedish studies on like-sexed adult twin pairs aged 18-47 (total of 20 056 pairs). Finnish men were heavier consumers of tobacco and alcohol than Swedish men. When heavy consumers (greater than 500g of alcohol/month and greater than 20 cigarettes/day) were considered, the prevalence rate was 9.7% in Finnish men and 5.1% in Swedish men. This difference might account for the higher morbidity in Finland than in Sweden from many smoking- and alcohol-associated diseases. Genetic factors in smoking and alcohol use were assessed by comparing observed and expected coincidence rates, and by multivariate analyses. Genetic and familial effects were defined as an excess coincidence in monozygotic (MZ) pairs compared to dizygotic (DZ) pairs, and by an increased DZ coincidence rate compared to that expected. Significant genetic and familial effects were observed for cigarette smoking, and for smoking more than one pack of cigarettes a day. Significant familial effects for alcohol use was observed, and a significant genetic effect was obtained for men. A significant genetic effect could not be observed for the combined heavy use of alcohol and heavy smoking. The genetic and familial effects seemed to be mostly independent of country and sex.

Adult↗

PubMed1982

A cross-national epidemiological resource: the Swedish and Finnish cohort studies of like-sexed twins.

Two large-scale studies of adult like-sexed twin pairs are ongoing in Sweden and Finland. Both studies comprise an unselected series that has been studied in a comparable fashion. Zygosity determination and health questionnaire data-gathering were carried out in 1973 for the Swedish study and in 1975 for the Finnish study for the comparable age groups. Data on hospital usage, cancer incidence and mortality are collected by record-linkage from the respective national registries. Cross-national twin studies can permit testing of hypotheses of the relationships between genetic and cultural factors and major chronic diseases and their risk factors.

Adult↗

PubMed1980

Assessment of heritability for personality, based on a short-form of the Eysenck Personality Inventory: a study of 12,898 twin pairs.

The influence of genetic factors for two personality dimensions was analyzed using data from 12,898 unselected twin pairs of the Swedish Twin Registry. The heritability index was 0.50 (men) and 0.58 (women) for psychosocial instability. Corresponding figures for psychosocial extraversion were 0.54 and 0.66. Thus, about half the phenotypic variation may be attributed to genetic factors.

Adult↗

PubMed1977

'Workload' and risk of myocardial infarction--a prospective psychosocial analysis.

The study group consisted of 5187 building construction workers aged 41-61 in Greater Stockholm who had all responded to a psychosocial questionnaire and had been in full-time work without long-lasting illness episodes in the year before the study. A factor analysis of about 60 psychosocial variables was performed, and on this basis three indices were formed. The study group was followed for two years in official registers yielding information on morbidity and mortality. The 'workload' index was demonstrated to be significantly associated with subsequent risk of myocardial infarction.

Adult↗