McClearn G E, Svartengren M, Pedersen N L, Heller D A, Plomin R
Program in Biobehavioral Health, College of Health and Human Development, Pennsylvania State University.
J Gerontol. 1994 Nov;49(6):264-8. doi: 10.1093/geronj/49.6.m264.
In addition to their value in assessing pulmonary health and disease, spirometric variables have been shown to be powerful predictors of time until death in aging populations. The sources of variability in these spirometric values are consequently of relevance to basic gerontological research, and also of potential value in clinical application. The objective of this study was to estimate genetic and environmental sources of variance in pulmonary function.
The study involved 230 Swedish twin pairs (mean age = 64.9 years), of which number 37 monozygotic (MZ) pairs and 72 dizygotic (DZ) pairs had been separated and reared apart. Comparing these groups to the 57 MZ and 64 DZ pairs reared together permits stronger interpretation than that of conventional twin studies. Measures of vital capacity (VC) and forced expiratory volume in one second (FEV1) were residualized for height, age, sex, and tobacco consumption in pack-years.
Maximum likelihood analyses of VC and FEV1 gave heritability estimates of .48 and .67, respectively. Age effects were explored both by dividing the sample into two cohorts, respectively above and below 65 years, and by moving interval analysis. In the two-cohort analysis, heritabilities were somewhat higher for the older cohort than the younger cohort for FEV1. The opposite was true for VC: heritability was lower in the older cohort, and there was evidence for a shared rearing environmental effect for this group. Moving interval analysis suggests these differences are gradual rather than saltatory. There were no gender differences in parameter estimates.
Genetic factors account for between one-half and two-thirds of the variability in pulmonary function. There is a suggestion of age differences in the relative importance of genetic and environmental influences.
除了在评估肺部健康和疾病方面的价值外，肺功能测定变量已被证明是老年人群直至死亡时间的有力预测指标。因此，这些肺功能测定值的变异性来源与基础老年学研究相关，在临床应用中也具有潜在价值。本研究的目的是估计肺功能变异的遗传和环境来源。
该研究涉及230对瑞典双胞胎（平均年龄 = 64.9岁），其中37对同卵双胞胎（MZ）和72对异卵双胞胎（DZ）是分开抚养长大的。将这些组与一起抚养长大的57对MZ和64对DZ双胞胎进行比较，比传统双胞胎研究能得出更强有力的解释。肺活量（VC）和一秒用力呼气量（FEV1）的测量值针对身高、年龄、性别和以包年计算的烟草消费量进行了残差分析。
对VC和FEV1的最大似然分析得出遗传率估计值分别为0.48和0.67。通过将样本分为两个队列（分别为65岁以上和以下）以及移动区间分析来探讨年龄效应。在双队列分析中，FEV1方面，老年队列的遗传率比年轻队列略高。VC则相反：老年队列的遗传率较低，并且有证据表明该组存在共同抚养环境效应。移动区间分析表明这些差异是渐进的而非跳跃式的。参数估计中没有性别差异。
遗传因素占肺功能变异性的二分之一到三分之二。遗传和环境影响的相对重要性存在年龄差异的迹象。
