Background
The BROUHAHA study responded to a growing scientific need to better understand how environmental exposures influence short-term physiological responses in real-life conditions. Although the study did not aim to investigate cancer at this initial stage, its focus on environmental noise exposure and acute cardiometabolic responses is highly relevant for cancer research. Indeed, exposure to noise has been shown to disturb sleep, trigger stress, and stimulate excessive secretion of cortisol and adrenaline, leading to inflammation and metabolic disturbances—biological pathways that may intersect with mechanisms implicated in carcinogenesis.
 
Objectives
The Brouhaha study aimed to assess short-term noise exposure and variations in cardiometabolic markers measured with e-health devices in the E3N-Generations Cohort.

Methods
In total, 120 participants from the second generation of the E3N-Generations cohort residing in the Île-de-France and Auvergne-Rhône-Alpes regions (France) were enrolled in three successive waves. During 7 days, each participant was equipped with connected devices designed to measure environmental noise and physiological markers. In addition, mobile applications were installed on their phone. These included:
continuous noise dosimeters, worn throughout the day to quantify real?time exposure to environmental noise;
a GPS tracker application to link noise measurements collected by the dosimeter to geographic locations;
NoiseCapture mobile application, which provides geolocated noise measurements
e-health devices (a connected watch for physical activity, heart rate and sleep measurements, a tensiometer for blood pressure measurements, and a blood glucose sensor);
MyFoodRepo application, to record realtime dietary intake through photo-based meals and drinks,
digital daily questionnaires designed to contextualize exposure by documenting perceived stress, medication, adherence to the protocol.Finally, each participant collected his/her blood on dried blood spot cards, twice a day (morning and evening) over two days.
Each participant received all the equipment individually, accompanied by pedagogical and technical support to guarantee correct installation and optimal functioning of all tools and applications.

Results
Participants were recruited in three waves, requiring outreach to 821–1,057 cohort members per wave, and ultimately resulted in the inclusion of 104 participants across the three waves between March and September 2025. Participants ranged in age from 36 to 73 years (mean 54, ±7) and included 73 women and 31 men.
All participants completed the seven-day monitoring protocol. At least 90% of glucose measurements were successfully recorded for 79% of participants, and 65% of participants completed all four scheduled measurements for blood pressure monitoring. Daily follow-up questionnaires were fully completed each day by 63% of participants. Additionally, 96% of participants indicated that they would be willing to repeat the protocol. Data analyses are still ongoing, and the detailed results will be presented at the congress.

Conclusion
The Brouhaha study highlights the potential of integrating wearable technologies and monitoring to generate datasets in population-based research. In cancer research, this approach provides a framework for capturing rapid responses to environmental stressors, including stress activation, circadian disruption, and inflammatory signaling. Demonstrating adherence and technical reliability, the study lays a foundation for future research linking environmental exposures, stress responses, and long-term health outcomes relevant to cancer.