Final answer:
The risk factor model is used at the individual level primarily for personalized health planning. It allows for the prediction of disease risk based on genome analysis and guides individual lifestyle modifications and medical interventions to prevent disease onset and promote better health outcomes.
Step-by-step explanation:
The risk factor model is useful at the individual level, primarily for D. Personalized Health Planning. Genomic analysis can predict disease risks and help in devising specific health strategies for individuals. For example, genome sequencing might reveal a genetic predisposition to certain diseases which can be mitigated through lifestyle changes and medical interventions before the onset of the disease. These interventions are particularly effective for diseases arising from a single gene mutation and can also be relevant for polygenic diseases influenced by environmental factors, such as diet for heart disease. Moreover, understanding behavioral risk factors enables individuals to make healthier lifestyle choices, significantly reducing the risk of noninfectious diseases like cardiovascular diseases, diabetes, and some cancers. This preventive approach based on individual risk assessment can lead to better health outcomes and longevity, underscoring the utility of risk factor models in personal health planning.