Headache and Hormone Use Among Transgender Population in Thailand: A Cross-Sectional Online Study

• gender-affirming hormone therapy (Drug): Current or previous use of gender-affirming hormone therapy as part of the participant's usual care. Information about medication name, dose, route, frequency, duration, and adherence will be collected through an online questionnaire. The researchers will not assign or modify hormone therapy.
• Gender-Affirming Surgery (Procedure): History of gender-affirming surgery received as part of the participant's usual care. The type and date of surgery will be collected through an online questionnaire. No surgical procedure will be assigned or performed as part of this study.
• HIV Pre-Exposure Prophylaxis (Drug): Current or previous use of HIV pre-exposure prophylaxis as part of the participant's usual care. Information about PrEP use will be collected through an online questionnaire. The researchers will not prescribe or modify PrEP as part of this study.

Primary outcomes

• Prevalence of Headache [At enrollment during the one-time online questionnaire]: Number and percentage of participants who report headache in 1 year based on the structured online headache questionnaire.
• Clinical Characteristics of Headache [At enrollment during the one-time online questionnaire]: Number and percentage of participants reporting headache characteristics, including headache location, pain quality, aggravation by physical activity, nausea or vomiting, sensitivity to light, sensitivity to sound, aura symptoms, and reported headache triggers.

Secondary outcomes

• Prevalence of Migraine [At enrollment during the one-time online questionnaire]: Number and percentage of participants who screen positive for migraine based on the ID Migraine and American Migraine Prevalence and Prevention/American Migraine Study questionnaires.
• Headache-Related Disability Assessed Using the Migraine Disability Assessment Questionnaire [During the 3 months before enrollment]: Headache-related disability measured using the total Migraine Disability Assessment (MIDAS) score. Higher scores indicate greater headache-related disability.
• Association Between Gender-Affirming Hormone Therapy Use and Headache [At enrollment during the one-time online questionnaire]: Association between current or previous gender-affirming hormone therapy (GAHT) use and the presence of headache, as assessed by a self-reported headache item in the study questionnaire. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio
• Association Between Gender-Affirming Surgery and Headache [At enrollment during the one-time online questionnaire]: Association between a history of gender-affirming surgery and the presence of headache, as assessed by a self-reported headache item in the study questionnaire. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio
• Association Between HIV Pre-Exposure Prophylaxis Use and Headache [At enrollment during the one-time online questionnaire]: Association between current or previous HIV pre-exposure prophylaxis (PrEP) use and the presence of headache, as assessed by a self-reported headache item in the study questionnaire. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio
• Association Between Gender-Affirming Hormone Therapy Use and Migraine [At enrollment during the one-time online questionnaire]: Association between current or previous gender-affirming hormone therapy (GAHT) use and the presence of migraine, assessed using the ID Migraine and American Migraine Prevalence and Prevention/American Migraine Study questionnaires.. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio
• Association Between Gender-Affirming Surgery and Migraine [At enrollment during the one-time online questionnaire]: Association between a history of gender-affirming surgery and the presence of migraine, as assessed by the ID Migraine and American Migraine Prevalence and Prevention/American Migraine Study questionnaires. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio
• Association Between HIV Pre-Exposure Prophylaxis Use and Migraine [Time Frame: At enrollment during the one-time online questionnaire]: Association between current or previous HIV pre-exposure prophylaxis (PrEP) use and the presence of migraine, as assessed by the ID Migraine and American Migraine Prevalence and Prevention/American Migraine Study questionnaires. The association will be estimated using logistic regression and reported as an odds ratio with a 95% confidence interval. Unit of Measure: Odds ratio

Sex: All, ages: 18 Years to any, accepts healthy volunteers

Inclusion Criteria:

* Age 18 years or older
* Self-identifies as transgender
* Currently attends or has previously attended the Tangerine Clinic in Bangkok, Thailand
* Able to understand the study information and provide electronic informed consent
* Able to complete the online study questionnaire

Exclusion Criteria:

* Alcohol or drug use, or a medical condition that, in the investigator's judgment, could interfere with completion of the study procedures or the ability to provide informed consent
* A medical condition known to cause a secondary headache disorder unrelated to migraine, such as head trauma, a structural brain lesion, or an infection

• Results publication: Trovao Diniz E, Rocha Leite JB, Ribeiro Coutinho Madruga C, Maia Arca V, Macedo Cavalcanti Albuquerque JA, Sampaio Rocha-Filho PA. Headache in transgender men using gender-affirming hormone therapy: A case-control study. Headache. 2025 Sep;65(8):1449-1456. doi: 10.1111/head.14944. Epub 2025 Apr 18. PMID 40251852
• Results publication: Zavala LJ, Gil Ramirez A, Vetvik KG, Jensen RH, Hougaard A. Headache in individuals undergoing hormone therapy for gender transition: A cross-sectional, observational study. Headache. 2026 Mar;66(3):725-732. doi: 10.1111/head.15076. Epub 2025 Oct 16. PMID 41103036
• Results publication: Yalinay Dikmen P, Ertas M, Kosak S, Cimentepe C, Kocoglu M, Oztosun G, Direk Tecirli N, Onur Aysevener E. Primary headaches among gender dysphoric female-to-male individuals: A cross-sectional survey on gender transition experience. Headache. 2021 Sep;61(8):1194-1206. doi: 10.1111/head.14203. Epub 2021 Aug 31. PMID 34463974
• Results publication: Hranilovich JA, Kaiser EA, Pace A, Barber M, Ziplow J. Headache in transgender and gender-diverse patients: A narrative review. Headache. 2021 Jul;61(7):1040-1050. doi: 10.1111/head.14171. PMID 34363408

• Prakit Anukoolwittaya, M.D., Principal investigator, Chulalongkorn University
• Sirawit Roongrojwittayakul, M.D., Principal investigator, Ratchaburi Hospital
• Akarin Hiransuthikul, M.D., M.Sc., Study director, Chulalongkorn University
• Sekh Thanprasertsuk, M.D., Study director, Chulalongkorn University
• Jakkrapatara Boonruang, M.D., Study director, Institute of HIV Research and Innovation