Kim BJ, et al. - Using data from the Korea National Health and Nutrition Examination Surveys, researchers conducted a nationally representative population-based, cross-sectional study to examine the relationship of serum TSH and free T4 with handgrip strength (HGS) in euthyroid elderly. Particularly in older men, serum TSH level at the lower end of reference range might be related to low muscle strength.

Methods

• The study sample consisted of 650 men aged ≥50 years and 533 postmenopausal women.
• Researchers measured HGS using a digital grip strength dynamometer, and low muscle strength was characterized based on the Korean specific cutoff point of HGS (28.9 and 16.8 kg in men and women, respectively).

Results

• Findings suggested an association of lower serum TSH with lower HGS but not free T4 in men (P=0.032) after adjustment for confounders.
• It was noted that those with low-normal TSH consistently exhibited 5.0% lower HGS (P=0.027), with a linear decrease in HGS across decreasing serum TSH quartiles (P for trend = 0.018) vs men with high-normal TSH.
• Data reported that men with low muscle strength had 22.0% lower serum TSH than those without (P=0.015).
• They found that the odds for the risk of low muscle strength was 3.76 times higher among men with low-normal TSH than it was among those with high-normal TSH (P=0.021).
• They did not find these associations in postmenopausal women.