No.	Item	Guide questions/description	Response/page number
Domain 1: Research team and reflexivity
Personal characteristics
1.	Interviewer/facilitators	Which author/s conducted the interview?	Page 6 (Procedures): Reported in Methods under Procedures section.
2.	Credentials	What were the researcher’s credentials?	Page 6 (Procedures): The interviewer was a research assistant (bilingual, trained at the MA level in global health with experience in qualitative research).
3.	Occupation	What was their occupation at the time of the study?	Page 6 (Procedures): The interviewer was a research assistant at the time of the study.
4.	Gender	Was the researcher male or female	Page 6 (Procedures): The interviewer identified as female.
5.	Experience and training	What experience or training did the researcher have?	Page 6 (Procedures): The interviewer is bilingual and has experience in qualitative research, with an MA in global health. She also has experience as a translator and leading Spanish-language outreach programs.
Relationship with participants
6.	Relationship established	Was a relationship established prior to the study commencement?	The interviewer had no prior relationships with the research participants. SWL, ABS, and SL had prior relationships with some of the community centers where recruitment occurred, based on outreach work.
7.	Participant knowledge of the interviewer	What did the participants know about the researcher? E.g. personal goals, reasons for doing the research.	Research participants were aware of the goals of the study based on information provided by the interviewer at the time of recruitment and consent.
8.	Interviewer characteristics	What characteristics were reported about the interviewer/facilitator? e.g. Bias, assumptions, reasons and interests in the research topic.	No characteristics were reported to participants.
Domain 2: Study design
Theoretical framework
9.	Methodological orientation and theory	What methodological orientation was stated to underpin the study? E.g. grounded theory, discourse analysis, ethnography, phenomenology, content analysis.	Page 6–7 (Data Analysis): Qualitative content analysis was used to identify key themes.
Participant selection
10.	Sampling	How were participants selected? E.g. purposive, convenience, consecutive, snowball	Page 5–6 (Participants): We used purposive and snowball sampling to recruit participants.
11.	Method of approach	How were participants approached? (e.g. face-to-face, telephone, mail, email)	Page 5–6 (Participants): We used ads, flyers, and a face-to-face approach.
12.	Sample size	How many participants were in the study?	Page 7 (Sample Characteristics): 30 participants were interviewed.
13.	Non-participation	How many people refused to participate or dropped out? Reasons?	Not applicable - all who signed up for interviews took part. No one dropped out.
Setting
14.	Setting of data collection	Where was the data collected? E.g. home, clinic, workplace	Page 6 (Procedures): interviews were conducted at community sites chosen by the participants.
15.	Presence of non-participants	Was anyone else present besides the participants and researchers?	Not applicable - no other people were present during the interviews.
16.	Description of sample	What are the important characteristics of the sample (e.g. demographic data)	Page 7 (Sample Characteristics); Table 1
Data Collection
17.	Interview guide	Were questions, prompts, guides provided by the authors? Was it pilot tested?	Page 6 (Procedures): Interview guide was developed by a multidisciplinary team based on a review of literature and topics identified during brain health education outreach.
18.	Repeat interviews	Were repeat interviews carried out? If yes, how many?	Not applicable - interviews were only conducted once.
19.	Audio/visual recording	Did the research use audio or visual recording to collect the data?	Page 6 (Procedures): Audio recordings were collected.
20.	Field notes	Were field notes made	Not applicable - the data consisted of interview transcripts.
21.	Duration	What was the duration of the interviews or focus groups?	Page 6 (Procedures): Interviews lasted 45–60 minutes.
22.	Data saturation	Was data saturation discussed?	Page 6 (Data Analysis): Data saturation was reached.
23.	Transcripts returned	Were transcripts returned to participants for comment and/or correction?	Not applicable - transcripts were not returned to participants.
Domain 3: Analysis and findings
Data analysis
24.	Number of data coders	How many data coders coded the data?	Page 6–7 (Data Analysis): Data was analyzed by two coders (SWL, ABS) using content analysis to identify key themes.
25.	Description of the coding tree	Did authors provide a description of the coding tree?	Page 7–16 (Results)
26.	Derivation of themes	Were themes identified in advanced or derived from the data?	Page 6–7 (Data Analysis): Themes were derived both inductively and deductively.
27.	Software	What software, if applicable, was used to manage the data?	Page 6 (Procedure): Interviews were analyzed in Dedoose Version 8.3.17.
28.	Participant checking	Did participants provide feedback on the findings?	Not applicable - participants did not provide feedback on the findings.
Reporting
29.	Quotations presented	Were participant quotations presented to illustrate the themes/findings? What each quotation identified? E.g. participant number.	Page 7–16 (Results)
30.	Data and findings consistent	Was there consistency between the data presented and the findings?	Page 7–16 (Results): Findings presented represent the data.
31.	Clarity of major themes	Were major themes clearly presented in the findings?	Page 7–16 (Results): Major themes are presented in our results.
32.	Clarity of minor themes	Is there a description of diverse cases or discussion of minor themes?	Page 7–16 (Results): Within each theme, we also discuss a diversity of responses.