To the Editor.— The recent article by Drs. Boukhris and Becker in the March 6, 1972, issue ofThe Journaldocuments nicely the previously noted association between calcification of the abdominal aorta and osteoporosis. The authors speculate that calcium adsorbed from osteoporotic bones might be preferentially deposited in the arterial intima, but otherwise do not discuss mechanisms which might lead to the association which they describe. Absence of this discussion reflects the very limited degree to which the etiology and pathogenesis of osteoporosis are understood. Our recent experience suggests that the perpetual villain, cigarette smoking, may be a prominent, but presently unappreciated factor in this etiology, and thereby at least partially explains the association reported. Having observed that patients with symptomatic osteoporosis before age 65 included a striking predominance of heavy habitual smokers, we examined all appropriate and retrievable records from the three small local hospitals. This search yielded data