Rebollo Irene, Boomsma Dorret I
Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 1, NL-1081 BT Amsterdam, The Netherlands.
Psychosom Med. 2006 May-Jun;68(3):437-42. doi: 10.1097/01.psy.0000204631.76684.28.
There is a dose-response positive relationship between type A behavior (TABP) and cardiovascular disease-related symptoms. Estimates of heritability for TABP from previous studies vary; this might be explained by limitations in the sizes and compositions of the samples.
This study combines a large sample size, twin and parental, data from males and females, two generations of young adults and older adults, and the use of structural equation modeling (SEM) and full information maximum likelihood (FIML) estimation. To assess TABP, the Jenkins Activity Survey (JAS) was collected from MZ and DZ twins and their parents (n = 1670 twin families). Structural equation modeling is used to evaluate and estimate the effects of additive and nonadditive genetic effects, nonshared environmental effects, and competitive sibling interaction.
Forty-five percent of the variance in TABP was the result of genetic factors (28% were additive and 17% were nonadditive). The remaining 55% of the variance was explained by environmental factors not shared by the members of the same family. Competitive sibling interaction effects were not significant. There was no evidence of sex differences either in variances or means.
Understanding the sources of variance on TABP is important for therapy and prevention. According to the present results, the relevant environmental factors for the development of TABP are not shared by the members of the same family. The genetic portion of the variance is also worth considering for therapeutic purposes. Although the genetic code cannot be altered, its effects on behavior may be modifiable through the treatment of the biological mediators.
A型行为模式（TABP）与心血管疾病相关症状之间存在剂量反应正相关关系。以往研究对TABP遗传力的估计各不相同；这可能是由于样本大小和构成的局限性所致。
本研究结合了大样本量、双胞胎及父母的数据，涵盖男性和女性、两代年轻成年人及老年人，并运用结构方程模型（SEM）和全信息最大似然估计（FIML）。为评估TABP，从同卵双胞胎（MZ）和异卵双胞胎（DZ）及其父母（n = 1670个双胞胎家庭）中收集了詹金斯活动调查（JAS）。采用结构方程模型来评估和估计加性和非加性遗传效应、非共享环境效应以及竞争性同胞互动的影响。
TABP中45%的变异是由遗传因素导致的（28%为加性遗传，17%为非加性遗传）。其余55%的变异由同一家庭成员未共享的环境因素解释。竞争性同胞互动效应不显著。在变异或均值方面均无性别差异的证据。
了解TABP变异的来源对于治疗和预防至关重要。根据目前的结果，TABP发展的相关环境因素并非同一家庭成员所共享。变异的遗传部分在治疗方面也值得考虑。尽管遗传密码无法改变，但其对行为的影响可能通过对生物介质的治疗来调节。
