Subgroups can be defined using various criteria, including: - Demographic Factors: Age, sex, race, ethnicity, and marital status. - Socioeconomic Factors: Income level, education, occupation, and housing status. - Behavioral Factors: Smoking, alcohol consumption, physical activity, and diet. - Clinical Factors: Presence of comorbidities, genetic predispositions, and previous medical history. - Geographic Factors: Urban vs. rural residence, region, and environmental exposures.
