The Association of Thyroid Function With Bone Density During Childhood.

Abstract

Although the skeleton is a well-known thyroid hormone target organ, very little data are available on the association of thyroid function with bone outcomes during childhood. To study the association of thyroid function with bone mass during childhood. Population-based prospective cohort including 4204 children with TSH and free T4 (FT4) measured at the age of 6 years. Bone density was assessed by a total body dual-energy X-ray absorptiometry scan at the median age of 6 years (95% range, 5.6 to 7.9) and at the age of 10 years (95% range, 9.0 to 10.9) in 4204 and 3404 participants, respectively. There was an inverse association of TSH with bone mineral density (BMD) at the age of 6 (β -0.028 ± 0.011, P = 0.009) and with follow-up measurements at the age of 10 (β -0.027 ± 0.011, P = 0.014), but not with bone mineral content (BMC) at the age of 6 (β -0.028 ± 0.015, P = 0.06) or for follow-up measurements of BMC at the age of 10 (β -0.011 ± 0.015, P = 0.47). There was an inverse association of FT4 with BMD (β -0.016 ± 0.006, P = 0.014) and BMC (β -0.023 ± 0.009, P = 0.009) cross-sectionally, and also at the age of 10 years (BMD: β -0.018 ± 0.007, P = 0.007; BMC: β -0.021 ± 0.009, P = 0.020). A higher FT4 concentration is associated with lower bone mass at the age of 6 and at the age of 10 years. These data provide insights into the effects of thyroid function on bone physiology during childhood.