**5. Impact of thyroid hormone treatment on bone metabolism**

Effects of thyroid replacement therapy or thyroid suppressive therapy on bone mineral density (BMD) are controversial. Results of previous studies are confounded by differences in study design, insufficient prospective data and small numbers of subjects. In the population study by Vestergaard et al (2005), the use of anti-thyroid drugs was associated with a significantly reduced fracture risk, no effect of levothyroxine on fracture risk was observed. No influence of L-thyroxine therapy on BMD was reported in young adults with congenital hypothyroidism (Salerno et al, 2004). Recently published population based casecontrol study has demonstrated a significantly increased fracture risk in adults over 70 years treated by levothyroxine (Turner et al, 2011). Publications on the association between the thyroid replacement and suppressive treatments and the bone mineral metabolism will be discussed.
