Olausson P O, Lichtenstein P, Cnattingius S
Department of Medical Epidemiology, Karolinska Institute, Stockholm, Sweden.
Twin Res. 2000 Mar;3(1):23-7. doi: 10.1375/136905200320565652.
The aims of the present study were to evaluate the contribution of the genetic and environmental factors to the risk of teenage childbearing, and to study whether life style, socio-economic conditions, and personality traits could explain possible familial effects. We linked two population-based registers: the Swedish Twin Register and the Swedish Medical Birth Register. The study covers female twin pairs born between 1953 and 1958, having their first infant before the age of 30 years (n = 1885). In order to separate familial effects from other environmental influences, and genetic effects from shared environmental effects, only complete twin pairs with known zygosity were included, in all 260 monozygotic and 370 dizygotic twin pairs. We used quantitative genetic analyses to evaluate the importance of genetic and environmental effects for liability to teenage childbearing. Logistic regression analyses were used to estimate the effects of life style, socio-economic situation, and personality on the probability of teenage childbearing, and to study whether psychosocial factors could explain possible familial effects. Fifty-nine percent (0-76%) of the variance in being a teenage mother was attributable to heritable factors; 0% (0-49%) was due to shared environmental factors; and 41% (23-67%) was explained by non-shared environmental factors. Thus, the data were consistent with the hypothesis that the familial aggregation of teenage childbearing is completely explained by genetic factors, although the alternative hypothesis that familial aggregation is entirely explained by shared environmental factors cannot be ruled out. Significant effects of smoking habits, housing conditions, and educational level were found in relation to liability to teenage childbearing. However, the familial effects on risk of teenage childbearing were not mediated through similarities in life style and socio-economic factors. When studying risk factors for teenage childbearing, it is recommended to include life style and socio-economic variables as well as information about family history of teenage childbearing. Twin Research (2000) 3, 23-27.
本研究的目的是评估遗传和环境因素对青少年生育风险的影响，并研究生活方式、社会经济状况和人格特质是否能够解释可能存在的家族效应。我们将两个基于人群的登记册进行了关联：瑞典双胞胎登记册和瑞典医学出生登记册。该研究涵盖了1953年至1958年出生、在30岁之前生育第一胎的女性双胞胎对（n = 1885）。为了将家族效应与其他环境影响区分开来，以及将遗传效应与共同环境效应区分开来，仅纳入了已知合子性的完整双胞胎对，共计260对同卵双胞胎和370对异卵双胞胎。我们使用定量遗传分析来评估遗传和环境因素对青少年生育易感性的重要性。采用逻辑回归分析来估计生活方式、社会经济状况和人格对青少年生育概率的影响，并研究心理社会因素是否能够解释可能存在的家族效应。成为青少年母亲的差异中有59%（0 - 76%）可归因于遗传因素；0%（0 - 49%）归因于共同环境因素；41%（23 - 67%）由非共同环境因素解释。因此，数据与以下假设一致，即青少年生育的家族聚集完全由遗传因素解释，尽管不能排除家族聚集完全由共同环境因素解释的替代假设。发现吸烟习惯、住房条件和教育水平与青少年生育易感性存在显著关联。然而，家族对青少年生育风险的影响并非通过生活方式和社会经济因素的相似性来介导。在研究青少年生育的风险因素时，建议纳入生活方式和社会经济变量以及青少年生育家族史的信息。《双胞胎研究》（2000年）第3卷，第23 - 27页
