Causal life course research examining consequences of early-life exposures has largely relied on associations between early-life environments and later-life outcomes using exogenous environmental shocks. Nonetheless, even with (quasi-)randomized early-life exposures, these associations may reflect not only causation (“scarring”) but also selection (i.e., which members are included in data assessing later life). Investigating this selection and its impacts on estimated effects of early-life conditions has, however, often been ignored because of a lack of pre-exposure data. This study proposes an approach for assessing and correcting selection, separately from scarring, using genetic measurements. Because genetic measurements are determined at the time of conception, any associations with early-life exposures should be interpreted as selection. Using data from the UK Biobank, we find that in utero exposure to a higher area-level infant mortality rate is associated with genetic predispositions correlated with better educational attainment and health. These findings point to the direction and magnitude of selection from this exposure. Corrections for this selection in examinations of effects of exposure on later educational attainment suggest underestimates of 26–74%; effects on other life course outcomes also vary across selection correction methods.

中文翻译：

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利用遗传数据分离疤痕效应和生命早期暴露的选择

因果生命历程研究检查早期生命暴露的后果，很大程度上依赖于早期生活环境与使用外源环境冲击的晚年结果之间的关联。尽管如此，即使是（准）随机的早期生命暴露，这些关联也可能不仅反映了因果关系（“疤痕”），而且还反映了选择（即，哪些成员被纳入评估晚年生活的数据中）。然而，由于缺乏暴露前数据，调查这种选择及其对生命早期状况的估计影响的影响常常被忽视。这项研究提出了一种使用遗传测量来评估和纠正选择的方法，与疤痕分开。由于遗传测量是在受孕时确定的，因此与生命早期暴露的任何关联都应解释为选择。利用英国生物银行的数据，我们发现，在子宫内暴露于较高地区婴儿死亡率与遗传倾向相关，而遗传倾向又与更好的教育程度和健康状况相关。这些发现指出了这次曝光的选择方向和程度。在暴露对以后受教育程度影响的检查中对这一选择的修正表明低估了 26-74%；不同选择校正方法对其他生命历程结果的影响也有所不同。