Evidence map›Paper›PMID 35436963›Full record

ArticleEnvironmental health : a global access science source2022

Extended two-stage designs for environmental research.

Francesco Sera, Antonio Gasparrini

Erratum issuedAbstract read
In one paragraph

Article in Environmental health : a global access science source, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 61 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
61citing papers in PubMed, 2 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

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

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

61 citing papers in PubMed, 2 syntheses or guidelines pooled it.

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  7. Heat- and Cold-Associated Mortality in Germany, 2000-2023.Deutsches Arzteblatt international · 2026
    Observational
  8. Heat Stress and Placental Abruption: A Space-Time Stratified Case-Crossover Study.BJOG : an international journal of obstetrics and gynaecology · 2026
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1 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

2 authors.

Francesco SeraDepartment of Statistics, Computer Science and Applications "G. Parenti", University of Florence, Florence, Italy. francesco.sera@unifi.it.ORCID 0000-0002-8890-6848
Antonio GasparriniDepartment of Public Health, Environments and Society, London School of Hygiene & Tropical Medicine, London, UK.

Funding

Medical Research Council MR/M022625/1
6 · The paper itself

Abstract

backgroundThe two-stage design has become a standard tool in environmental epidemiology to model multi-location data. However, its standard form is rather inflexible and poses important limitations for modelling complex risks associated with environmental factors. In this contribution, we illustrate multiple design extensions of the classical two-stage method, all implemented within a unified analytic framework.

methodsWe extended standard two-stage meta-analytic models along the lines of linear mixed-effects models, by allowing location-specific estimates to be pooled through flexible fixed and random-effects structures. This permits the analysis of associations characterised by combinations of multivariate outcomes, hierarchical geographical structures, repeated measures, and/or longitudinal settings. The analytic framework and inferential procedures are implemented in the R package mixmeta.

resultsThe design extensions are illustrated in examples using multi-city time series data collected as part of the National Morbidity, Mortality and Air Pollution Study (NMMAPS). Specifically, four case studies demonstrate applications for modelling complex associations with air pollution and temperature, including non-linear exposure-response relationships, effects clustered at multiple geographical levels, differential risks by age, and effect modification by air conditioning in a longitudinal analysis.

conclusionsThe definition of several design extensions of the classical two-stage design within a unified framework, along with its implementation in freely-available software, will provide researchers with a flexible tool to address novel research questions in two-stage analyses of environmental health risks.

Indexed as

Air PollutantsAir PollutionEnvironmental ExposureHumansLinear ModelsMeta-Analysis as TopicSoftwareTemperatureTime FactorsAir PollutantsEnvironmental epidemiologyMeta-analysisPollutionTemperatureTwo-stage design

Identifiers

PMID35436963
PMCPMC9017054

What OpenQuestion holds

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LicenceCC BY
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Registered trials

None linked

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.