Dataset Information

Imputation Procedures for Cognitive Variables in the Mexican Health and Aging Study: Evaluating the Bias from Excluding Participants with Missing Data.

ABSTRACT: Non-response of cognitive data in cohort studies is a barrier to cognitive aging research. We describe the procedures for the imputation of non-responses for cognitive data in the Mexican Health and Aging Study (MHAS). Data came from the 2001-2015 MHAS waves. We also describe the association of cognition with education, age, and other variables in 2015 with and without the imputed values. Between 12.3% and 37.9% of participants were missing data for at least one cognition variable. When we conducted the analysis with and without the imputed values, the relationships between education, age, and cognition were similar in direction and significance, but different in magnitude. Non-response of cognitive data is common and non-random in the MHAS. Investigators should use the data sets that include the imputed values, which are publicly available.

SUBMITTER: Downer B

PROVIDER: S-EPMC8553231 | biostudies-literature | 2021 May-Aug

REPOSITORIES: biostudies-literature

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Publications

Imputation Procedures for Cognitive Variables in the Mexican Health and Aging Study: Evaluating the Bias from Excluding Participants with Missing Data.

Downer Brian B Avila Jaqueline J Chen Nai-Wei NW Wong Rebeca R

Realidad, datos y espacio : revista internacional de estadistica y geografia 20210501 2

Non-response of cognitive data in cohort studies is a barrier to cognitive aging research. We describe the procedures for the imputation of non-responses for cognitive data in the Mexican Health and Aging Study (MHAS). Data came from the 2001-2015 MHAS waves. We also describe the association of cognition with education, age, and other variables in 2015 with and without the imputed values. Between 12.3% and 37.9% of participants were missing data for at least one cognition variable. When we condu ...[more]

PMID: 34721821

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Project description:BackgroundEpidemiological and clinical studies often have missing data, frequently analysed using multiple imputation (MI). In general, MI estimates will be biased if data are missing not at random (MNAR). Bias due to data MNAR can be reduced by including other variables ("auxiliary variables") in imputation models, in addition to those required for the substantive analysis. Common advice is to take an inclusive approach to auxiliary variable selection (i.e. include all variables thought to be predictive of missingness and/or the missing values). There are no clear guidelines about the impact of this strategy when data may be MNAR.MethodsWe explore the impact of including an auxiliary variable predictive of missingness but, in truth, unrelated to the partially observed variable, when data are MNAR. We quantify, algebraically and by simulation, the magnitude of the additional bias of the MI estimator for the exposure coefficient (fitting either a linear or logistic regression model), when the (continuous or binary) partially observed variable is either the analysis outcome or the exposure. Here, "additional bias" refers to the difference in magnitude of the MI estimator when the imputation model includes (i) the auxiliary variable and the other analysis model variables; (ii) just the other analysis model variables, noting that both will be biased due to data MNAR. We illustrate the extent of this additional bias by re-analysing data from a birth cohort study.ResultsThe additional bias can be relatively large when the outcome is partially observed and missingness is caused by the outcome itself, and even larger if missingness is caused by both the outcome and the exposure (when either the outcome or exposure is partially observed).ConclusionsWhen using MI, the naïve and commonly used strategy of including all available auxiliary variables should be avoided. We recommend including the variables most predictive of the partially observed variable as auxiliary variables, where these can be identified through consideration of the plausible casual diagrams and missingness mechanisms, as well as data exploration (noting that associations with the partially observed variable in the complete records may be distorted due to selection bias).

Dataset Information

Imputation Procedures for Cognitive Variables in the Mexican Health and Aging Study: Evaluating the Bias from Excluding Participants with Missing Data.

Publications

Imputation Procedures for Cognitive Variables in the Mexican Health and Aging Study: Evaluating the Bias from Excluding Participants with Missing Data.

Similar Datasets

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