Health has long been conceived as not just the absence of disease but also the presence of physical, psychological, and social well-being. Nonetheless, the traditional medical model focuses on specific organ system diseases. This representative study of US older adults living in their homes amassed not only comprehensive medical information but also psychological and social data and measured sensory function and mobility, all key factors for independent living and a gratifying life. This comprehensive model revealed six unique health classes, predicting mortality/incapacity. The healthiest people were obese and robust; two new classes, with twice the mortality/incapacity, were people with healed broken bones or poor mental health. This approach provides an empirical method for broadly reconceptualizing health, which may inform health policy.

Abstract

The World Health Organization (WHO) defines health as a “state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” Despite general acceptance of this comprehensive definition, there has been little rigorous scientific attempt to use it to measure and assess population health. Instead, the dominant model of health is a disease-centered Medical Model (MM), which actively ignores many relevant domains. In contrast to the MM, we approach this issue through a Comprehensive Model (CM) of health consistent with the WHO definition, giving statistically equal consideration to multiple health domains, including medical, physical, psychological, functional, and sensory measures. We apply a data-driven latent class analysis (LCA) to model 54 specific health variables from the National Social Life, Health, and Aging Project (NSHAP), a nationally representative sample of US community-dwelling older adults. We first apply the LCA to the MM, identifying five health classes differentiated primarily by having diabetes and hypertension. The CM identifies a broader range of six health classes, including two “emergent” classes completely obscured by the MM. We find that specific medical diagnoses (cancer and hypertension) and health behaviors (smoking) are far less important than mental health (loneliness), sensory function (hearing), mobility, and bone fractures in defining vulnerable health classes. Although the MM places two-thirds of the US population into “robust health” classes, the CM reveals that one-half belong to less healthy classes, independently associated with higher mortality. This reconceptualization has important implications for medical care delivery, preventive health practices, and resource allocation.