Investigation
Do Bluetooth earbuds expose the head to stronger radiofrequency (RF) fields than phones—and cause brain tumours?
Qualifies
The 2024 Zhou et al. primary questionnaire/modeling paper distributed 1,000 questionnaires, retained 600 valid responses and 393 Bluetooth-headset users, then selected 48 respondents reporting thyroid nodules and 48 without for a balanced 96-person modeling set. Its reported XGBoost AUC 0.95 and SHAP importance for use duration do not quantify RF dose, diagnose nodules by imaging, establish prospective incidence or demonstrate a causal thyroid or brain effect.