Abstract
A normal value is a laboratory parameter to discriminate between "normal" and "abnormal" in clinical decision-making. Because individual differences in the elderly are large, it can be difficult to determine a normal value as a group, thus reference values are basically used to assess laboratory parameters. However, the reference value only shows the range of average values in the healthy population, and does not determine or predict present and future health status. In geriatric practice, reference values of laboratory parameters in life-style related disease to predict independent life is indispensable. Although there are many risk factors of cognitive impairment related to independent life, the contribution rate of each factor is small and it is often difficult to determine a cut-off point by conventional methods. A new methodology is required to determine the optimal range of clinical parameter of life-style-related disease using longitudinal data.
