We investigate long-term cognitive effects of an intervention, where systolic blood pressure (sBP) is monitored at more optimal levels, in a large representative sample. A limitation with previous research on the potential risk reduction of such interventions is that they do not properly account for the reduction of mortality rates. Hence, one can only speculate whether the effect is a result from changes in cognition or changes in mortality. As such, we extend previous research by providing both an etiological and a prognostic effect estimate. To do this we propose a Bayesian semi-parametric estimation approach for an incremental intervention, using the extended G-formula. We also introduce a novel sparsity-inducing Dirichlet hyperprior for longitudinal data, demonstrate the usefulness of our approach in simulations, and compare the performance relative to other Bayesian decision tree ensemble approaches. In our study, there were no significant prognostic- or etiological effects across all ages, indicating that sBP interventions likely do not have a strong effect on memory neither at the population level nor at the individual level.

翻译：我们基于一个大规模代表性样本，探讨了将收缩压（sBP）维持在更优化水平的干预措施对认知功能的长期影响。既往关于此类干预措施潜在风险降低效果的研究存在局限性，即未能充分考虑死亡率下降的影响。因此，当前学界只能推测该效应源于认知变化还是死亡率变化。为此，我们通过同时提供病因学效应和预后效应估计值来拓展既往研究。我们提出了一种基于扩展G公式的贝叶斯半参数估计方法，用于评估增量干预的效果；同时引入了一种新颖的纵向数据稀疏化Dirichlet超先验分布，通过模拟实验验证了该方法的有效性，并将其性能与其他贝叶斯决策树集成方法进行了比较。本研究发现，各年龄段均未观察到显著的预后或病因学效应，表明收缩压干预措施在群体层面和个体层面均可能对记忆力无显著影响。