Department of Psychiatry, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8134, St Louis, MO 63110, USA.
Addiction. 2009 Sep;104(9):1512-8. doi: 10.1111/j.1360-0443.2009.02648.x.
To estimate the magnitude of genetic and environmental influences on timing of first alcohol use and alcohol dependence (AD) and to quantify the overlap in these influences across the two alcohol-related outcomes.
The sample consisted of 5382 twins (2691 complete pairs), aged 24-36 years, from the Australian Twin Registry.
History of alcohol use and DSM-IV alcohol dependence were assessed by structured telephone interview.
In both sexes, the relationship between age at first alcohol use and risk for AD followed a linear trend, such that the highest rates of AD were observed in individuals who began drinking at an earlier than average age (14 years or younger). Heritability estimates for timing of first alcohol use and AD were 36% and 53%, respectively. Shared environmental factors accounted for 15% of variance in initiation. There was no evidence of shared environmental influences on AD. The genetic correlation between timing of first alcohol use and AD was 0.59.
Findings highlight the substantial role of genetics in the development of AD and the early manifestation of that genetic risk in the timing of alcohol use initiation which, unlike AD, is also influenced to a modest degree by shared environmental factors. The considerable overlap in heritable influences-and the virtual absence of overlap in individual-specific environmental influences-on initiation of alcohol use and AD indicates that the association between age at first drink and AD is attributable in large part to common genetic sources of variance.
评估遗传和环境因素对首次饮酒和酒精依赖（AD）时间的影响程度，并量化这两种与酒精相关的结果之间的影响重叠。
该样本由来自澳大利亚双胞胎登记处的 5382 对双胞胎（2691 对完整双胞胎）组成，年龄在 24-36 岁之间。
通过结构化电话访谈评估饮酒史和 DSM-IV 酒精依赖。
在男性和女性中，首次饮酒年龄与 AD 风险之间的关系呈线性趋势，即饮酒年龄较早（14 岁或更早）的个体 AD 发生率最高。首次饮酒时间和 AD 的遗传度估计值分别为 36%和 53%。共享环境因素解释了起始阶段 15%的变异。AD 不存在共享环境影响的证据。首次饮酒时间和 AD 之间的遗传相关性为 0.59。
研究结果强调了遗传因素在 AD 发病机制中的重要作用，以及遗传风险在饮酒起始时间上的早期表现，与 AD 不同，后者也受到共享环境因素的适度影响。首次饮酒时间和 AD 之间可遗传影响的高度重叠，以及个体特定环境影响的几乎不存在重叠，表明首次饮酒年龄与 AD 之间的关联主要归因于常见的遗传变异源。
