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Education policy and the heritability of educational attainment.

https://arctichealth.org/en/permalink/ahliterature65600
Source
Nature. 1985 Apr 25-May 1;314(6013):734-6
Publication Type
Article
Author
A C Heath
K. Berg
L J Eaves
M H Solaas
L A Corey
J. Sundet
P. Magnus
W E Nance
Source
Nature. 1985 Apr 25-May 1;314(6013):734-6
Language
English
Publication Type
Article
Keywords
Achievement
Education
Educational Status
Environment
Female
Genetics
Humans
Intelligence
Pregnancy
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Sex Factors
Twins
Abstract
Many workers assume that genetically determined differences in intellectual ability will be influenced little by changes in educational policy or other environmental interventions. Others, however, have suggested that increasing equality of educational opportunity will lead to an increase in the heritability of educational attainment. The resolution of this issue has been delayed until now because of the extremely large sample sizes which would be required. Education data on twins and their parents, from the Norwegian twin panel, provide a unique opportunity to determine the impact on the heritability of educational attainment of the more liberal social and educational policies introduced in Norway after the Second World War. As reported here, for individuals born before 1940 there is a strong effect of family background on educational attainment, accounting for 47% of the variance, though genetic factors account for an additional 41% of the variance. For females born after 1940 and before 1961, the relative importance of genetic (38-45%) and familial environmental (41-50%) differences changes very little. For males born during the same period, the broad heritability of educational attainment has increased substantially (67-74%), and the environmental impact of family background has correspondingly decreased (8-10%). For males, at least, having well-educated parents no longer predicts educational success, as measured by duration of education, independent of the individual's own innate abilities.
PubMed ID
4039415 View in PubMed
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The effect of perinatal screening in Norway on the magnitude of noninherited risk factors for congenital dislocation of the hip.

https://arctichealth.org/en/permalink/ahliterature38968
Source
Am J Epidemiol. 1987 Feb;125(2):271-6
Publication Type
Article
Date
Feb-1987
Author
A A Kramer
K. Berg
W E Nance
Source
Am J Epidemiol. 1987 Feb;125(2):271-6
Date
Feb-1987
Language
English
Publication Type
Article
Keywords
Cross-Sectional Studies
Delivery, Obstetric
Female
Hip Dislocation, Congenital - epidemiology - etiology
Humans
Infant, Newborn
Male
Norway
Parity
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Twins
Abstract
Several investigators have noted an increase in the rate of congenital dislocation of the hip shortly after the initiation of neonatal screening procedures. This increase has been attributed to the detection of temporarily unstable hips which require no corrective treatment. To test whether neonatal screening had low specificity, the authors obtained data on 17,145 offspring of 7,896 twins from the Norwegian Twin Panel. Information from maternal reproduction history questionnaires was available on the presence or absence of congenital dislocation of the hip, type of obstetric delivery, and parity. The reported prevalence of the disorder did indeed begin to rise sharply during the late 1950s, at which time neonatal screening started in Norway. Infants were then grouped by year of birth (born before or after 1960), and odds ratios were calculated for breech delivery and early (first or second) parity. For the pre-screening group, the odds ratio of congenital dislocation of the hip was 7.7 among children delivered by breech presentation and 2.6 among those of early parity. These values are similar to those found in other studies. In the post-screening group, the odds ratios for breech delivery and early parity were 1.5 and 1.2, respectively. Breech delivery and early parity have been consistent risk factors for congenital dislocation of the hip. Their diminished influence in the post-screening group, as well as sharply increased rates of the disorder, suggests that in Norway neonatal screening programs may have had low specificity in detecting cases that required treatment.
PubMed ID
3492911 View in PubMed
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The epidemiology of pregnancy complications and outcome in a Norwegian twin population.

https://arctichealth.org/en/permalink/ahliterature64894
Source
Obstet Gynecol. 1992 Dec;80(6):989-94
Publication Type
Article
Date
Dec-1992
Author
L A Corey
K. Berg
M H Solaas
W E Nance
Author Affiliation
Department of Human Genetics, Medical College of Virginia, Richmond.
Source
Obstet Gynecol. 1992 Dec;80(6):989-94
Date
Dec-1992
Language
English
Publication Type
Article
Keywords
Female
Humans
Male
Marital status
Norway - epidemiology
Pregnancy
Pregnancy Complications - epidemiology
Pregnancy Outcome - epidemiology
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Twins - genetics
Abstract
OBJECTIVE: To measure the contribution of genetic factors to selected pregnancy complications, including miscarriage, twinning, hypertension-toxemia, and nausea-vomiting. METHODS: Information on 22,241 pregnancies of 8675 female twins or spouses of male twins was obtained by questionnaire from members of the population-based Norwegian Twin Panel. Comparisons of observed tetrachoric correlations were used to assess the importance of genetic influences on the variables examined. RESULTS: Pregnancy history information was provided by both members of 830 monozygotic and 902 dizygotic female twin pairs and by the spouses of both members of 459 monozygotic and 464 dizygotic male twin pairs. The incidence of twin pregnancy in general, and of opposite-sexed twins in particular, found among dizygotic twin women was nearly twice that observed for any other group. Monozygotic female twin pairs were more concordant than dizygotic female twin pairs for the occurrence of miscarriage, nausea or vomiting during pregnancy, and hypertension or overt toxemia. A similar pattern of twin similarity was observed for the use of certain medications during pregnancy including vitamins, aspirin, and nausea medication. CONCLUSIONS: Maternal genetic factors make an important contribution to a predisposition for dizygotic twinning, contribute to the risk of miscarriage, and appear to determine, in part, whether a woman experiences nausea-vomiting or hypertension-toxemia during pregnancy. In addition, health-seeking behaviors of women during pregnancy, as reflected by the use of several classes of medication, appear to be influenced somewhat by genetic factors.
PubMed ID
1448270 View in PubMed
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Familial aggregation of congenital dislocation of the hip in a Norwegian population.

https://arctichealth.org/en/permalink/ahliterature233763
Source
J Clin Epidemiol. 1988;41(1):91-6
Publication Type
Article
Date
1988
Author
A A Kramer
K. Berg
W E Nance
Author Affiliation
Department of Social and Preventive Medicine, SUNY, Buffalo 14214.
Source
J Clin Epidemiol. 1988;41(1):91-6
Date
1988
Language
English
Publication Type
Article
Keywords
Diseases in Twins
Female
Hip Dislocation, Congenital - epidemiology - genetics
Humans
Male
Marriage
Mothers
Norway
Probability
Abstract
Previous studies of congenital dislocation of the hip have not used adequate control groups in estimating the level of genetic influence on that trait. Furthermore, it could not be demonstrated that alleged maternal effects were not an artifact of reporting bias. To that end, information was obtained on the presence of the anomaly in the families of adult twins and their spouses participating in the Norwegian Twin Registry. The prevalence odds ratio for having that disorder in first degree relatives was 10.0. Stratifying by class of relatives, the prevalence odds ratio was 8.1 for fathers, 35.8 for mothers, 12.7 for siblings, and 3.3 for offspring. The increased prevalence odds ratio for mothers over that of fathers suggests a maternal effect. Since both males and females reported on the anomaly for each parental type, it is unlikely that the difference in prevalence odds ratios is due to general reporting bias.
PubMed ID
3335875 View in PubMed
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The heritability of smoking behaviour in pregnancy, and the birth weights of offspring of smoking-discordant twins.

https://arctichealth.org/en/permalink/ahliterature60292
Source
Scand J Soc Med. 1985;13(1):29-34
Publication Type
Article
Date
1985
Author
P. Magnus
K. Berg
T. Bjerkedal
W E Nance
Source
Scand J Soc Med. 1985;13(1):29-34
Date
1985
Language
English
Publication Type
Article
Keywords
Birth weight
Comparative Study
Female
Genetics, Behavioral
Humans
Infant, Newborn
Pregnancy
Prenatal Exposure Delayed Effects
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Smoking
Twins
Twins, Dizygotic
Twins, Monozygotic
Abstract
Questionnaire information on smoking habits in pregnancy was collated in 341 monozygotic (MZ) and 321 dizygotic (DZ) female twin pair cases from a population-based Norwegian Twin Panel. In a multifactorial model, the intra-pair correlation in smoking was 0.797 (+/- 0.042) in monozygotic (MZ) and 0.443 (+/- 0.075) in dizygotic (DZ) twin pairs, indicating a substantial genetic influence on liability to smoke in pregnancy. The questionnaire information was linked with birth records in the Medical Birth Registry of Norway, and birth weights of offspring of 62 MZ and 100 DZ smoking-discordant twin pairs were studied. Offspring of smoking MZ twins weighed 127 g less than birth order matched offspring of the non-smoking co-twins. This finding is additional evidence that smoking is a direct cause of reduced birth weight in offspring.
PubMed ID
3992213 View in PubMed
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The influence of secular effects and gravidity on the rate of ectopic pregnancy in a Norwegian population.

https://arctichealth.org/en/permalink/ahliterature65472
Source
Int J Epidemiol. 1987 Sep;16(3):431-5
Publication Type
Article
Date
Sep-1987
Author
G M Buck
A A Kramer
W E Nance
K. Berg
Author Affiliation
Department of Social and Preventive Medicine, School of Medicine, State University of New York, Buffalo 14214.
Source
Int J Epidemiol. 1987 Sep;16(3):431-5
Date
Sep-1987
Language
English
Publication Type
Article
Keywords
Diseases in Twins
Epidemiologic Methods
Female
Humans
Norway
Parity
Pregnancy
Pregnancy, Ectopic - epidemiology - etiology
Abstract
In order to assess the influence of secular effects and gravidity on the incidence rate of ectopic pregnancy, information from reproductive history questionnaires was obtained for 7804 gravid females identified through the Norwegian Twin Panel. The overall ectopic pregnancy incidence rate was 5.6 per 1000 estimated conceptions, with rates increasing for women born after 1950. Women experiencing their first pregnancy were at lowest risk for that pregnancy being ectopic. When women were stratified by whether they were born before or after 1950, gravidity still had an effect on the incidence rate of ectopic pregnancy. Conversely, year of birth was influential when stratifying by gravidity. The results obtained here suggest that the recent increase in the incidence of ectopic pregnancy is unrelated to the number of prior pregnancies.
PubMed ID
3667043 View in PubMed
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The occurrence of epilepsy and febrile seizures in Virginian and Norwegian twins.

https://arctichealth.org/en/permalink/ahliterature65040
Source
Neurology. 1991 Sep;41(9):1433-6
Publication Type
Article
Date
Sep-1991
Author
L A Corey
K. Berg
J M Pellock
M H Solaas
W E Nance
R J DeLorenzo
Author Affiliation
Department of Human Genetics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0033.
Source
Neurology. 1991 Sep;41(9):1433-6
Date
Sep-1991
Language
English
Publication Type
Article
Keywords
Diseases in Twins - epidemiology - genetics
Epilepsy - epidemiology - genetics
Female
Humans
Male
Norway - epidemiology
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.
Seizures, Febrile - epidemiology - genetics
Twins, Dizygotic
Twins, Monozygotic
Virginia - epidemiology
Abstract
Twin studies provide an efficient method for examining the importance of genetic and environmental factors in the etiology of disorders such as epilepsy. Population-based twin registries are especially valuable for studies of this type since effects of reporting and self-selection biases on the resulting data are minimized. Among 14,352 twin pairs contained in the Virginia and Norwegian twin panels for whom questionnaire information was available, there was a history of epilepsy in one or both members of 286 pairs; febrile seizures were reported in 257 pairs. Analyses of questionnaire data revealed no significant differences in concordance rates between Virginian and Norwegian twins for either epilepsy or febrile seizures. Probandwise concordance rates for epilepsy were 0.19 in monozygotic twins and 0.07 in dizygotic twins. Analogous rates for febrile seizures were 0.33 (monozygotic) and 0.11 (dizygotic). These results provide further evidence that genetic factors do have a role in the expression of epilepsy and febrile seizures.
PubMed ID
1891093 View in PubMed
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14 records – page 1 of 2.