Table 1 Search strategy and selection procedure

One

(Initial search in PubMed and Wiley Web of Science)

ALL (“enrol”*) AND (“health insurance” OR “NHIS”) AND (“individual facilitators” OR “individual enablers”) (“older adults” OR older people OR “adults”)

Two

(search across, Scopus, PsycINFO, Science Direct, Ovid, and Sage)

ALL (“enrol”* OR “register”* OR “join”) AND (“health insurance” OR “NHIS” OR “health protection”) AND (“predisposing” OR “need” OR “enabling” OR “motivations”) AND (“older adults” OR older people OR “adults” OR “older folks” OR “older individuals”) (“enrol”* OR “register”* OR “join” OR “subscribe”) AND (“health insurance” OR “NHIS” OR “health protection” OR “health cover”) AND (“personal factors” OR “enablers” OR “motivators” OR “motivations” OR “drivers” OR “stimulus”) AND (“older adults” OR older people OR “adults” OR “older folks” OR “older individuals” OR “elderly”)

Three

Hand searching of the reference lists