PMC:7795804 / 19337-19664 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T114","span":{"begin":0,"end":150},"obj":"Sentence"},{"id":"T115","span":{"begin":151,"end":327},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"The results of this study should be interpreted with caution as they derive from a cross-sectional design, which makes causal inferencing challenging. Moreover, the survey sampling was based on an online invitation, which does not allow for generalization because the population that does not use the Internet was not explored."}