The results from the currents study should be interpreted in the light of 3 limitations. First, the analyses are limited to men, and therefore cannot be extended to women. Second, the sample comprises only native Virginians of Caucasian origin. The results should therefore be generalized with caution to other male populations. Last, the unstable influences on the occasion-specific measures of LTH-AD and error of measurement, are not necessarily unimportant factors (Carey and Gottesman, 1978). They could comprise aspects valid to a general clinical evaluation, like failing memory, poor communication with the interviewer, or distracting events that happened the day of the interview. Therefore, the factors conceptualized as error of measurement in this study could be of importance in other studies.
