Scalable Big Data Platform With End-to-End Traceability for Health Data Monitoring in Older Adults: Development and Performance Evaluation.

Background: The increasing use of real-time health data from wearable devices and self-reported questionnaires offers significant opportunities for preventive care in aging populations. However, current health data platforms often lack built-in mechanisms for data and model traceability, version control, and coordinated management of heterogeneous data streams, which are essential for clinical accountability, regulatory compliance, and reproducibility. The absence of these features limits the reuse of health data and the reproducibility of analytical workflows across research and clinical environments. Objective: This work presents DeltaTrace, a unified big data health platform designed with traceability as a key architectural feature. The platform integrates end-to-end tracking of data and model versions with real-time and batch processing capabilities. Built entirely on open source technologies, DeltaTrace combines components for data management, model management, orchestration, and visualization. The main objective is to demonstrate that embedding traceability within the architecture enables scalable, auditable, and version-controlled processing of health data, thereby facilitating reproducible analytics and long-term maintenance of health monitoring systems. Methods: DeltaTrace adopts a medallion architecture implemented with Delta Lake to ensure atomic and version-controlled data transformations. Apache Spark is used for distributed computation, Apache Kafka for continuous data ingestion, and Apache Airflow for orchestration of batch and streaming workflows. MLflow manages the lifecycle and versioning of machine learning models, while Grafana provides visualization dashboards for real-time and aggregated data inspection. The platform is evaluated using continuous physiological signals from wearable devices and batch-ingested questionnaire data, combining synthetic and real data from the LifeSnaps dataset. Performance tests are conducted on central processing unit-only servers with 8-core and 24-core configurations to assess ingestion, aggregation, visualization, and anomaly detection latency. Results: DeltaTrace supports continuous processing for approximately 1500 users with end-to-end delays below 10 minutes. Ingestion and visualization tasks operate between mean 4.9 (SD 0.12) and 7.5 (SD 0.28) minutes, while aggregation and anomaly detection required less than mean 5.6 (SD 0.04) and 10.5 (SD 1.70) minutes, respectively. Increasing from 8 to 24 cores improved ingestion and cleaning latency by up to 25% and anomaly detection performance by up to 50%. The system maintains consistent performance across different data types, processing modes, and loads. Conclusions: DeltaTrace provides a scalable and modular architecture that incorporates traceability as a core component together with functions for model management, orchestration, and visualization. The platform enables complete version control across data and models and maintains performance under limited hardware conditions. These characteristics support reproducible and auditable health data processing and make DeltaTrace suitable for continuous monitoring and preventive health care in aging populations.