PMC:7795804 / 20744-21099 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T121","span":{"begin":128,"end":336},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"es that certainly could not change during the study period and cannot be intermediate effectors of the other putative exposure. However, this approach does not allow us to rule out that some of the observed associations were not independent and could have been due to confounding or could have been mediated by other putative exposures.\nDespite these limi"}