The BHARAT study: a multi-modal, multi-omics investigation of aging signatures in the Indian population

India is undergoing a rapid demographic transition, with its elderly population projected to exceed 347 million by 2050. Although aging is the primary risk factor for multiple chronic diseases, most biological age (BA) models have been developed for Western populations, with limited applicability to Indian demographics. The BHARAT study (Biomarkers of Healthy Aging, Resilience, Adversity, and Transitions) aims to develop and validate composite signatures of aging in the Indian population by integrating multi-omics, biochemical, clinical, and lifestyle data. The BHARAT study is a multi-center, cross-sectional observational study designed using a hub-and-spoke model, with the Indian Institute of Science (IISc) serving as the central hub for omics analyses, biobanking, and data integration. Participants are stratified into five age groups (18–29, 30–44, 45–59, 60–74, ≥75 years) with balanced rural–urban and gender representation. The study primarily includes healthy participants, excluding those with chronic diseases that are not resolved by medication. Data collection encompasses comprehensive clinical and cognitive assessments, lifestyle and quality-of-life questionnaires, and biological sampling (including blood, urine, stool, cheek swabs, and hair). Multi-omics profiling spans epigenomics, proteomics, metabolomics, lipidomics, metagenomics, and immune phenotyping, integrating untargeted discovery-based Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) with targeted assays under harmonized protocols and quality-controlled biobanking standards. As the first large-scale, discovery-driven aging cohort in India, BHARAT will generate population-specific reference datasets, (re)train and calibrate biological clocks, develop a data-driven framework for organ-specific clocks, and identify biomarkers of physiological resilience and decline. Given that presently this study is cross-sectional in design, it will help establish a scalable framework for subsequent longitudinal and translational research to develop context-specific diagnostics, predictive models, and therapeutic targets for healthy aging in India.