From health check-ups to "City sewage health scan": Multidimensional chemical analysis for wastewater-based epidemiology in Hong Kong.

Wastewater-based epidemiology (WBE) can provide a multidimensional "health check-up" for community-wide health. We conducted a "city sewage health scan" in Hong Kong by analyzing 401 time-proportional composite samples from 12 sewersheds over five weeks, classifying 117 biomarkers, referencing the local drug formulary and WHO ICD-11, into 45 features and seven health categories (infectious, endocrine, central nervous system, cardiovascular, respiratory, pain-related, and lifestyle). Our findings contextualized Hong Kong's longevity, showing that Hong Kong's biomarker levels are moderate globally, but with a relatively high burden of chronic disease and respiratory medications. Respiratory medication use was more strongly linked to ambient air quality-especially traffic-related CO-than to nicotine exposure, underscoring environmental factors associated with the respiratory burden. This multidimensional approach enables systematic mapping of health burdens and needs at intra-city level as well, highlighting the value of WBE for targeted public health monitoring. Furthermore, by comparing WBE-based estimates with traditional survey data, we demonstrate that WBE captures community-level pharmacotherapy for chronic conditions and reveals underreported antibiotic and tobacco use, supporting improved public health surveillance.