To the Editor: An important point in the study by Watts et al. (July 12 issue)* leaves the reader with questions about the validity of the study. With regard to the changes in the bone mineral density of the spine, group 1 — the double-placebo group — had an increase in spinal bone mineral density during the two-year study period. This increase is striking, since this group would be expected to have a decrease in spinal bone density with age. Have the authors an explanation for this increase? Furthermore, the authors did not comment on the slightly higher rates of. © 1990, Massachusetts Medical Society. All rights reserved.
