Abstract：
BACKGROUND: Empirical evaluation of inverse probability weighting (IPW) for self-selection bias correction is inaccessible without the full source population. We aimed to: (i) investigate how self-selection biases frequency and association measures and (ii) assess self-selection bias correction using IPW in a cohort with register linkage.
METHODS: The source population included 17 936 individuals invited to the Copenhagen Aging and Midlife Biobank during 2009-11 (ages 49-63 years). Participants counted 7185 (40.1%). Register data were obtained for every invited person from 7 years before invitation to the end of 2020. The association between education and mortality was estimated using Cox regression models among participants, IPW participants and the source population.
RESULTS: Participants had higher socioeconomic position and fewer hospital contacts before baseline than the source population. Frequency measures of participants approached those of the source population after IPW. Compared with primary/lower secondary education, upper secondary, short tertiary, bachelor and master/doctoral were associated with reduced risk of death among participants (adjusted hazard ratio [95% CI]: 0.60 [0.46; 0.77], 0.68 [0.42; 1.11], 0.37 [0.25; 0.54], 0.28 [0.18; 0.46], respectively). IPW changed the estimates marginally (0.59 [0.45; 0.77], 0.57 [0.34; 0.93], 0.34 [0.23; 0.50], 0.24 [0.15; 0.39]) but not only towards those of the source population (0.57 [0.51; 0.64], 0.43 [0.32; 0.60], 0.38 [0.32; 0.47], 0.22 [0.16; 0.29]).
CONCLUSIONS: Frequency measures of study participants may not reflect the source population in the presence of self-selection, but the impact on association measures can be limited. IPW may be useful for (self-)selection bias correction, but the returned results can still reflect residual or other biases and random errors.
METHODS: The source population included 17 936 individuals invited to the Copenhagen Aging and Midlife Biobank during 2009-11 (ages 49-63 years). Participants counted 7185 (40.1%). Register data were obtained for every invited person from 7 years before invitation to the end of 2020. The association between education and mortality was estimated using Cox regression models among participants, IPW participants and the source population.
RESULTS: Participants had higher socioeconomic position and fewer hospital contacts before baseline than the source population. Frequency measures of participants approached those of the source population after IPW. Compared with primary/lower secondary education, upper secondary, short tertiary, bachelor and master/doctoral were associated with reduced risk of death among participants (adjusted hazard ratio [95% CI]: 0.60 [0.46; 0.77], 0.68 [0.42; 1.11], 0.37 [0.25; 0.54], 0.28 [0.18; 0.46], respectively). IPW changed the estimates marginally (0.59 [0.45; 0.77], 0.57 [0.34; 0.93], 0.34 [0.23; 0.50], 0.24 [0.15; 0.39]) but not only towards those of the source population (0.57 [0.51; 0.64], 0.43 [0.32; 0.60], 0.38 [0.32; 0.47], 0.22 [0.16; 0.29]).
CONCLUSIONS: Frequency measures of study participants may not reflect the source population in the presence of self-selection, but the impact on association measures can be limited. IPW may be useful for (self-)selection bias correction, but the returned results can still reflect residual or other biases and random errors.
摘要：
背景：在没有完整的源种群的情况下，无法获得用于自我选择偏差校正的逆概率加权（IPW）的经验评估。我们的目标是：（i）调查自我选择如何偏差频率和关联措施，以及（ii）在具有注册链接的队列中使用IPW评估自我选择偏差校正。
方法：来源人群包括2009-11年间邀请到哥本哈根老龄化和中年生物样本库的17936人（年龄49-63岁）。参与者计数7185（40.1%）。从邀请前7年到2020年底，获得了每个受邀人的注册数据。使用Cox回归模型估计参与者之间的教育和死亡率之间的关联，IPW参与者和来源人群。
结果：受试者在基线前的社会经济地位较高，医院接触者较少。IPW后参与者的频率测量接近源人群的频率测量。与小学/初中教育相比，高中，短三级，学士和硕士/博士与参与者死亡风险降低相关(调整后风险比[95%CI]：0.60[0.46;0.77]，0.68[0.42;1.11]，0.37[0.25；0.54]，0.28[0.18;0.46]，分别)。IPW略微改变了估计值(0.59[0.45；0.77]，0.57[0.34;0.93]，0.34[0.23;0.50]，0.24[0.15；0.39]），但不仅针对源人群的人群（0.57[0.51；0.64]，0.43[0.32;0.60]，0.38[0.32;0.47]，0.22[0.16；0.29]）。
结论：研究参与者的频率测量可能无法反映存在自我选择的来源人群，但对关联措施的影响可能是有限的。IPW可用于(自)选择偏差校正，但是返回的结果仍然可以反映残差或其他偏差和随机误差。
方法：来源人群包括2009-11年间邀请到哥本哈根老龄化和中年生物样本库的17936人（年龄49-63岁）。参与者计数7185（40.1%）。从邀请前7年到2020年底，获得了每个受邀人的注册数据。使用Cox回归模型估计参与者之间的教育和死亡率之间的关联，IPW参与者和来源人群。
结果：受试者在基线前的社会经济地位较高，医院接触者较少。IPW后参与者的频率测量接近源人群的频率测量。与小学/初中教育相比，高中，短三级，学士和硕士/博士与参与者死亡风险降低相关(调整后风险比[95%CI]：0.60[0.46;0.77]，0.68[0.42;1.11]，0.37[0.25；0.54]，0.28[0.18;0.46]，分别)。IPW略微改变了估计值(0.59[0.45；0.77]，0.57[0.34;0.93]，0.34[0.23;0.50]，0.24[0.15；0.39]），但不仅针对源人群的人群（0.57[0.51；0.64]，0.43[0.32;0.60]，0.38[0.32;0.47]，0.22[0.16；0.29]）。
结论：研究参与者的频率测量可能无法反映存在自我选择的来源人群，但对关联措施的影响可能是有限的。IPW可用于(自)选择偏差校正，但是返回的结果仍然可以反映残差或其他偏差和随机误差。
