▪ Abstract  With an increasingly older population, there is considerable interest in understanding the potential for risk factor interventions in order to prevent, postpone, or slow down the common diseases seen in older persons. However, it is often reported that the strength of association between risk factors and common disease outcomes decreases with increasing age. Actually, many different age-related patterns are observed. Understanding these patterns requires knowledge of issues related to the pathophysiology of aging, including age-related physiologic and metabolic alterations, detection and diagnosis of disease in the elderly, measurement of risk factors, sample selection, comorbidity, competing risks, selective survival, ceiling effects, and methods of analysis in aging populations.