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Subclinical hypothyroidism unrelated to weight gain in older adults
Subclinical hypothyroidism does not appear to be an independent risk factor for weight gain in the elderly, according to findings from the Cardiovascular Health Study.
The current study utilized data from the longitudinal, population-based analysis of adults aged at least 65 years. The researchers identified for evaluation 427 subclinically hypothyroid participants and 2,864 participants with normal thyroid function. The study participants returned for annual evaluations throughout the study period, ending in 1999. These visits entailed a comprehensive medical history, physical examination and blood testing after a 12-hour fast. The blood samples were assayed for serum thyroid-stimulating hormone, free thyroxine and total triiodothyronine.
The researchers used generalized estimating equations to evaluate the association between annual weight change and thyroid status, measured both at a single time point (the 1992-1993 visit) and continuously for 2 years. A subset of 1,276 participants who underwent DXA scanning were assessed cross-sectionally for thyroid function and body weight.
The researchers found an overall weight loss during the follow-up (–0.38 kg/year for men, –0.37 kg/year for women). There was no association between subclinical hypothyroidism and weight change vs. euthyroidism, either at a single time point or continuously for 2 years. There also was no association between subclinical hypothyroidism and changes in lean mass, fat mass or fat percentage vs. patients with normal thyroid function.
In women only, there was an association between TSH level — 1 mU/L higher within the euthyroid or subclinical range and a 0.51-kg higher baseline weight (P<.001) — although this association did not apply to changes in weight in either gender. Also in women only, there was a relationship between a 1-ng/dL higher free T4 level and both lower baseline weight and 0.32-kg/year greater weight loss (P=.003).
The researchers said the nature of the cross-sectional relationship between TSH, free T4, weight and fat mass in older women remains unclear, adding that their study does not support the treatment of subclinical hypothyroidism in the elderly for weight-control purposes.
“Intentional weight loss in the elderly remains controversial, and our findings do not support the treatment of subclinical hypothyroidism to prevent weight gain or treat obesity in the elderly,” the researchers wrote.
Disclosure: The researchers report no relevant financial disclosures.