A Significant Association of Upper Limb Muscle Strength with Thyroid Function in Overweight and Obese Population: A Study of the Sixth Korea National Health and Nutrition Examination Survey (KNHANES 2014-2015)

Table 4

Relation of upper limb muscle strength with quartiles of TSH and FT4 in overweight and obese subjects (BM ≥23 kg/m²).

Age group	TSH				-value	FT4				-value
	Q1	Q2	Q3	Q4		Q1	Q2	Q3	Q4
Age 19–39 (n = 696)	40.88	39.25	39.82	38.41	0.0249	36.42	39.49	38.73	41.86	0.3236
Age ≥40 (n = 1285)	36.43	36.82	36.09	33.87	0.1533	33.32	35.62	36.61	38.74	0.0513

Corrected by sex, smoking, drinking, diabetes, and exercise. BMI, body mass index (calculated as weight divided by height squared (kg/m²)). FT4, free thyroxine. TSH, thyrotropin. TSH (mIU/L), Q1 ≤1.51, 1.51< Q2 ≤2.21, 2.21< Q3 ≤3.17, 3.17 Q4 ≤29.50. FT4 (ng/dL), Q1 ≤1.13, 1.13Q2 ≤1.23, 1.23 < Q3 ≤1.35, 1.35 < Q4 ≤1.76.