CONTROVERSY over whether levothyroxine sodium therapy causes bone mineral loss and osteoporosis has grown during the past decade, largely fueled by differences in the results of reported studies. This literature has been recently analyzed1 in the context of potentially differing effects of levothyroxine treatment when given in suppressive rather than replacement dosage, as defined by measurability of thyrotropin. The conclusions reached were that suppressive doses of levothyroxine in certain settings could be associated with loss of bone mineral density (BMD), whereas proof is lacking of a deleterious effect of levothyroxine on bone when it is given in a replacement dosage. The basis for the controversy appears to have related to the degree of known differences in a variety of potentially confounding factors, including study design (cross sectional vs longitudinal), patient population characteristics (age, race, ethnicity, sex, body mass, and menopausal status), type or duration of levothyroxine therapy (replacement