Evidence map›Paper›PMID 23211345›Full record

ArticleEpidemiology (Cambridge, Mass.)2013

Loss to follow-up in cohort studies: bias in estimates of socioeconomic inequalities.

Laura D Howe, Kate Tilling, Bruna Galobardes, Debbie A Lawlor

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Article in Epidemiology (Cambridge, Mass.), 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 183 papers, 9 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
183citing papers in PubMed, 9 pooled it
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1 · What the graph read from it

What it found

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

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3 · Its place in the literature

Who cites it

183 citing papers in PubMed, 9 syntheses or guidelines pooled it.

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123 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

4 authors.

Laura D HoweFrom the MRC Centre for Causal Analyses in Translational Epidemiology, School of Social & Community Medicine, University of Bristol, Bristol, UK. laura.howe@bristol.ac.uk
Kate Tilling
Bruna Galobardes
Debbie A Lawlor

Funding

Medical Research Council G0600705Medical Research Council G0900724Medical Research Council G1002375Medical Research Council G9815508Medical Research Council MC_UU_12013/5Wellcome Trust 089979Wellcome Trust 092731
6 · The paper itself

Abstract

backgroundAlthough cohort members tend to be healthy and affluent compared with the whole population, some studies indicate this does not bias certain exposure-outcome associations. It is less clear whether this holds when socioeconomic position (SEP) is the exposure of interest.

methodsAs an illustrative example, we use data from the Avon Longitudinal Study of Parents and Children. We calculate estimates of maternal education inequalities in outcomes for which data are available on almost the whole cohort (birth weight and length, breastfeeding, preterm birth, maternal obesity, smoking during pregnancy, educational attainment). These are calculated for the full cohort (n~12,000) and in restricted subsamples defined by continued participation at age 10 years (n∼7,000) and age 15 years (n∼5,000).

resultsLoss to follow-up was related both to SEP and outcomes. For each outcome, loss to follow-up was associated with underestimation of inequality, which increased as participation rates decreased (eg, mean birth-weight difference between highest and lowest SEP was 116 g [95% confidence interval = 78 to 153] in the full sample and 93 g [45 to 141] and 62 g [5 to 119] in those attending at ages 10 and 15 years, respectively).

conclusionsConsiderable attrition from cohort studies may result in biased estimates of socioeconomic inequalities, and the degree of bias may worsen as participation rates decrease. However, even with considerable attrition (>50%), qualitative conclusions about the direction and approximate magnitude of inequalities did not change among most of our examples. The appropriate analysis approaches to alleviate bias depend on the missingness mechanism.

Indexed as

Cohort StudiesData Interpretation, StatisticalHealth Status DisparitiesLost to Follow-UpSelection BiasSocioeconomic FactorsAdolescentBirth WeightBreast FeedingChildEducational StatusEnglandFemaleHumansInfant, NewbornModels, Statistical

Identifiers

PMID23211345
PMCPMC5102324

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.