Thyroid-stimulating hormone levels may be related to body weight

Small increases in serum thyroid-stimulating hormone concentrations within the reference range may be linked to weight gain, according to a recent study.

Researchers from the National Heart, Lung and Blood Institute’s Framingham Heart Study and other sites in Massachusetts analyzed 2,407 participants from the Framingham Offspring Study. The participants had baseline serum TSH concentrations of 0.5 to 5 mIU/L and follow-up concentrations of 0.5 to 10 mIU/L. None of the participants were taking thyroid hormone therapy and they all attended two consecutive routine exams.

According to the abstract, at baseline the women had an adjusted mean weight of 64.5 kg in the lowest TSH concentration quartile and 70.2 kg in the highest TSH concentration quartile; men had adjusted mean weight of 82.8 kg in the lowest quartile and 85.6 kg in the highest. Mean body weight increased by 1.5 kg in women and by 1.0 kg in men during 3.5 years of follow-up.

At follow-up, researchers found that an increase in TSH was associated with weight gain. In women, weight gain ranged from 0.5 to 2.3 kg across increasing quartiles of TSH concentration change (P<.001 for trend). In men, weight gain ranged from 0.4 to 1.3 kg across quartiles of TSH concentration change (P=.007), according to the study. – by Stacey L. Adams

Arch Intern Med. 2008;168:587-592.