Environmental and ethnic differences in short-term risk of first acute myocardial infarction: a prospective multiethnic cohort protocol.

The study will recruit 2,340 adults aged 20-85 years with an estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk of ≥20%.

• Participants will be enrolled from five hospitals in Gansu Province, China.
• The age range spans 20-85 years.
• Eligibility requires an estimated 10-year ASCVD risk ≥20%.
• The study targets a high-risk population to capture incident AMI events within the follow-up window.

The study will include four distinct ethnic populations representing variation in ethnicity, altitude, and healthcare access.

• Ethnic groups included are Han, Hui, Tibetan, and Kazakh populations.
• Recruitment sites were selected to represent variation in altitude and healthcare accessibility.
• Five hospitals across Gansu Province serve as recruitment centers.
• This multiethnic design allows comparison of AMI risk across populations with differing genetic backgrounds and environmental exposures.

Participants will be followed every 3 months for a total of 24 months with repeated measurements of behavioral, physiological, and biomarker indicators.

• Follow-up intervals are set at 3 months throughout the 24-month study period, yielding up to 8 repeated measurement occasions per participant.
• Repeated measures include behavioral, physiological, and biomarker indicators.
• Wearable electrocardiographic monitoring is included as part of the repeated assessment protocol.
• The frequent follow-up schedule is designed to capture short-term within-individual changes in risk indicators.

The primary outcome of the study is first incident acute myocardial infarction (AMI).

• Only participants without a prior AMI at baseline are eligible, making this an incident AMI study.
• Time-to-event models with time-varying variables will be used as the primary analytic approach.
• The analytic framework is designed to examine how within-individual changes in risk indicators are associated with AMI across environmental and ethnic contexts.
• Environmental exposures and healthcare accessibility will be assigned using geospatial data.

Baseline assessments will include standardized questionnaires, clinical evaluation, and cardiometabolic profiling alongside geospatially assigned environmental exposure data.

• Baseline data collection includes standardized questionnaires, clinical evaluation, and cardiometabolic profiling.
• Environmental exposures will be assigned to participants using geospatial data.
• Healthcare accessibility will also be characterized using geospatial methods.
• This combination of individual-level and area-level data enables examination of contextual influences on AMI risk.

The study protocol has received ethics approval and is registered as a clinical trial.

• The study has been approved by the Ethics Committee of Gansu Provincial Hospital.
• Written informed consent will be obtained from all participants.
• The trial is registered under ChiCTR2500104518.
• Findings will be disseminated through peer-reviewed publications and scientific presentations.

Current risk assessment approaches based on baseline measurements are identified as insufficient for capturing short-term AMI risk or population heterogeneity.

• The authors note that 'current risk assessment approaches based on baseline measurements may not adequately capture short-term risk or population heterogeneity.'
• AMI risk varies substantially across populations shaped by 'environmental conditions, geographic context, and healthcare accessibility.'
• The study's repeated-measures design with time-varying covariates is proposed as a methodological improvement over cross-sectional baseline approaches.
• AMI 'remains a leading cause of mortality worldwide' with substantial population-level variation.