Bias Due to Left Truncation and Left Censoring in Longitudinal Studies of Developmental and Disease Processes
Open Access
- 21 March 2011
- journal article
- research article
- Published by Oxford University Press (OUP) in American Journal of Epidemiology
- Vol. 173 (9), 1078-1084
- https://doi.org/10.1093/aje/kwq481
Abstract
In longitudinal studies of developmental and disease processes, participants are followed prospectively with intermediate milestones identified as they occur. Frequently, studies enroll participants over a range of ages including ages at which some participants’ milestones have already passed. Ages at milestones that occur prior to study entry are left censored if individuals are enrolled in the study or left truncated if they are not. The authors examined the bias incurred by ignoring these issues when estimating the distribution of age at milestones or the time between 2 milestones. Methods that account for left truncation and censoring are considered. Data on the menopausal transition are used to illustrate the problem. Simulations show that bias can be substantial and that standard errors can be severely underestimated in naïve analyses that ignore left truncation. Bias can be reduced when analyses account for left truncation, although the results are unstable when the fraction truncated is high. Simulations suggest that a better solution, when possible, is to modify the study design so that information on current status (i.e., whether or not a milestone has passed) is collected on all potential participants, analyzing those who are past the milestone at the time of recruitment as left censored rather than excluding such individuals from the analysis.Keywords
This publication has 15 references indexed in Scilit:
- "Persistence" improves the 60-day amenorrhea marker of entry to late-stage menopausal transition for women aged 40 to 44 yearsMenopause, 2010
- Statistical methods for estimating the probability of spontaneous abortion in observational studies—Analyzing pregnancies exposed to coumarin derivativesReproductive Toxicology, 2008
- Recommendations from a multi-study evaluation of proposed criteria for Staging Reproductive AgingClimacteric, 2007
- Conditions for Bias from Differential Left TruncationAmerican Journal of Epidemiology, 2006
- Evaluation of Four Proposed Bleeding Criteria for the Onset of Late Menopausal TransitionJournal of Clinical Endocrinology & Metabolism, 2006
- Semiparametric Analysis of Survival Data with Left Truncation and Dependent Right CensoringBiometrics, 2005
- Menstrual patterns leading to the final menstrual periodMenopause, 2002
- Executive summary: stages of reproductive aging workshop (STRAW)Fertility and Sterility, 2001
- Three stages of the menopausal transition from the Seattle Midlife Womenʼs Health Study: toward a more precise definitionMenopause, 2000
- VARIATION OF THE HUMAN MENSTRUAL CYCLE THROUGH REPRODUCTIVE LIFEObstetrical & Gynecological Survey, 1968