The Chinese Migrant Population Health Cohort is a prospective, multi-center study jointly initiated by Professor Yong Ji, President of Harbin Medical University, and Academician Guoqiang Chen, President of Hainan Medical University, in collaboration with regional partners. It targets older adults (≥60 years) who engage in seasonal migration between cold (Heilongjiang) and tropical (Hainan) regions. The primary objective is to investigate cardiovascular and metabolic disease risks, underlying biological and environmental mechanisms, and effective preventive strategies in this unique population.

Participants are recruited from both origin and destination sites and undergo standardized baseline assessments, including questionnaires, physical examinations, medical imaging, biospecimen collection (blood, stool, hair, nails), and environmental exposure monitoring. Longitudinal follow-up includes periodic reassessments, remote monitoring, and data linkage with hospital information systems to capture health outcomes.

The study aims to:

Define migration-related health risk profiles and disease phenotypes.

Elucidate biological and environmental mechanisms influencing disease onset and progression.

Develop AI-driven risk prediction models and evaluate targeted interventions through nested randomized controlled trials.

Translate findings into clinical guidelines and scalable cross-regional health management models.

This is the first cohort in China to systematically investigate the health impacts of seasonal migration in older adults. By integrating epidemiology, multi-omics, environmental data, and health policy translation, the study seeks to improve continuity of care, strengthen climate adaptation, and promote healthy ageing.

Inclusion Criteria:

1. Permanent residents of Harbin or Hainan who will continue to reside in Harbin or Hainan for the next 5 years.
2. Baseline age ≥60 years, with basic communication and comprehension abilities.
3. No confirmed diagnosis of end-stage major organic diseases (e.g., advanced heart failure, advanced liver failure, advanced kidney failure, malignant tumors).
4. Able to perform activities of daily living independently and capable of completing questionnaires and physical examinations.
5. Willing to participate in the study, provide written informed consent, accept long-term follow-up, and provide biological specimens.

Exclusion Criteria:

1. Occurrence of life-threatening acute events (e.g., myocardial infarction, acute heart failure, stroke) within the past 30 days.
2. Currently receiving chronic treatment with antiviral drugs (e.g., for HIV) or antipsychotic medications.
3. Presence of moderate to severe cognitive impairment preventing survey completion or follow-up cooperation.
4. Current acute infectious diseases such as influenza or fever.
5. Simultaneous participation in other interventional clinical studies.
6. Refusal to sign informed consent or unwillingness to provide biological specimens.
7. Any other condition deemed unsuitable for study participation by the investigators based on overall assessment.

The study will enroll community-dwelling adults aged ≥60 years from Harbin (cold region) and Hainan (tropical region), China. Four groups will be included: 1. Winter Migrant Group: ~5,000 Harbin residents who habitually migrate to Hainan during the cold season for ≥2 months each time, with ≥2 consecutive years of such migration and plans to continue; 2. Summer Migrant Group: ~1,000 Hainan residents who habitually migrate to Harbin during the hot season for ≥2 months, with similar migration history and plans; 3. Cold-Region Resident Group: ~10,000 Harbin residents, including matched controls for migrant groups and randomly selected residents, with no >2 months residence outside Harbin in the past 5 years; 4. Tropical-Region Resident Group: ~10,000 Hainan residents with similar matching criteria and residency requirements.

All participants must be able to communicate, perform daily activities independently, consent to long-term follow-up, and provide biospecimens.