Bone remodeling in old age: Longitudinal monitoring in Arizona

Beginning in October, 1982, annual monitoring of the density of the radius has been conducted on a population of affluent elderly citizens of Sun City, Arizona. In the summer of 1983, a second component of the project was added, drawing on residents of subsidized retirement residences in Tucson, Arizona. The study, now in its eighth year, has followed the procedure of collecting data on 225 individuals in each city each year, adding new subjects to compensate for attrition as needed. Total sample size in this mixed-longitudinal study presently stands at 1209. In order to develop normative standards for all age groups and allow construction of sex-specific bone density profiles for the two populations, additional subjects were recruited from the University community and from health monitoring projects in progress in the College of Medicine. The total sample is presently slightly over 2,000 individuals, approximately 1,500 of whom are women. In addition to bone mineral density data, collected with a Lunar SP-2 photon absorptiometer at a site located one-third of the distance from the distal end of the radius, comprehensive questionnaire data concerning medical history, current medications, exercise habits, and nutritional intakes were collected in the Sun City and Tucson longitudinal studies. One of the most significant findings of this study to date has been the sharp difference between the remodeling patterns observed in men as opposed to women. In addition, longitudinal observations show that bone loss follows a pattern that is more episodic than steady in both sexes.