Chen W J, Faraone S V, Orav E J, Tsuang M T
Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts.
Genet Epidemiol. 1993;10(1):43-59. doi: 10.1002/gepi.1370100106.
Since many disorders have a variable age at onset, knowing the age at onset distribution of a disease facilitates epidemiologic analyses in several ways. The age at onset distribution is commonly used to estimate morbidity risks or the recurrence risks in genetic counseling. Unfortunately, estimation of a disease's age at onset distribution is not straightforward. The observed age at onset distribution obtained from prevalent cases is usually used in these epidemiologic analyses. Through simulation studies, we show that, in certain situations, the observed age at onset distribution has a non-negligible downward bias. This bias can lead to a substantial underestimation of the morbidity risk or the recurrence risk. The simulations also demonstrate that a non-parametric approach for correcting the age at onset distribution works well even when mortality increases after onset. The results have implications for diseases that have adult onset and/or increased mortality after onset. We suggest that researchers should use corrected age at onset distributions, rather than relying on observed distributions, in the calculation of either morbidity risks or recurrence risks.
由于许多疾病的发病年龄各不相同，了解疾病的发病年龄分布有助于从多个方面进行流行病学分析。发病年龄分布通常用于估计遗传咨询中的发病风险或复发风险。不幸的是，估计疾病的发病年龄分布并非易事。在这些流行病学分析中，通常使用从现患病例中获得的观察到的发病年龄分布。通过模拟研究，我们表明，在某些情况下，观察到的发病年龄分布存在不可忽视的向下偏差。这种偏差可能导致对发病风险或复发风险的严重低估。模拟还表明，即使发病后死亡率增加，一种用于校正发病年龄分布的非参数方法也能很好地发挥作用。这些结果对成年发病和/或发病后死亡率增加的疾病具有启示意义。我们建议研究人员在计算发病风险或复发风险时，应使用校正后的发病年龄分布，而不是依赖观察到的分布。
