Statistical analysis of the organ weights in 1,000 autopsy cases of Japanese aged over 60 years.

For practical use in comparing organ weights of autopsy cases in the aged, and also for evaluating gerontological parameters during human senescence, a method of organ weight standardization was introduced. In the method used in this study, a Gaussian distribution was applied to the main peak that appeared in each distribution of organ weights. The Gaussian distribution best fitted the main peak of the distribution even in the elderly autopsy cases when a large number of cases was accumulated. The smaller peak was adopted in a cardiac weight distribution which showed a double peak because clinicopathological analysis to define a background of the double peak revealed that the larger peak was essentially represented by hypertensive hearts. By using the data from standardized values as well as those from arithmetic means and from means of each individual ratio, the following parameters were obtained: weight ratio of each organ to the body, and weight ratio of each organ and of the body to the brain. In these parameters, comparison of the ratios obtained from standardized values with those obtained by the other procedures showed that the age-related change in the ratios from standardized values were the most reasonably smooth and seemed to be less exaggerated by pathological changes. In elderly autopsy cases, organ changes due to geriatric disorders are difficult to distinguish from those due to ordinary physiological changes, which makes the estimation of "normal values" in the aged problematical. The standardized values obtained in the present study, however, represent mass ecological values and may be applicable as comprehensive practical values in geriatric autopsy pathology as well as in gerontological studies.