Increased Thyroid Hormone and Weight Gain

According to a new study, small increases in thyroid stimulating hormone can lead to weight gain. The news comes as the result of a large, community-based study, reported in the March 24 issue of the Archives of Internal Medicine.

Thyroid function is measureable by testing TSH (thyroid stimulating hormone) levels in the bloodstream. When thyroid hormone levels are out of balance, high or low, we know it can lead to weight gain or weight loss respectively.

"Our findings raise the possibility that modest increases in serum TSH concentrations within the reference range may be associated with weight gain", according to Caroline S. Fox, MD, MPH, from the National Heart, Lung, and Blood Institute's Framingham Heart Study in Framingham, Massachusetts, and colleagues.

Further studies are needed to define how much these modest increases are a contribution to weight gain and obesity. In this particular study, very modest increases in TSH concentrations resulted in weight gain in both women and men.

Arch Intern Med. 2008;168:568-569, 587-592.