Table 1.

Subject characteristics

Variable		Statistic
Heel quantitative ultrasound	N = 3231	Mean (SD)
BUA (dB/MHz)		80.3 (18.9)
SOS (m/s)		1550.9 (34.1)
QUI		97.8 (21.2)
Areal bone mineral density	N = 735	Mean (SD)
Lumbar spine (g/cm2)		1.055 (0.175)
Femoral neck (g/cm2)		0.807 (0.127)
Frailty index	N = 2450	n (%)
Low		2016 (82.3)
Medium		342 (14.0)
High		92 (3.8)
Fried frailty phenotype	N = 2965	n (%)
Robust		2110 (71.2)
Pre-frail		783 (26.4)
Frail		72 (2.4)
Components of Fried frailty phenotype	N = 2965	n (%)
Low physical activity		305 (10.3)
Exhaustion		239 (8.1)
Slowness		291 (9.8)
Weakness		198 (6.7)
Sarcopenia		168 (5.7)