Assessing Sarcopenia through DXA Measurements

Whole body composition, including lean soft tissue mass (lean mass) and fat mass, was measured at baseline using DXA (Hologic Discovery A densitometer) as per standard procedures.²⁷ ALM (kg), composed of at least 95% skeletal muscle, was computed as the sum of the upper and lower limbs lean mass and ALM index (ALMI) calculated by dividing ALM by height squared (m²). The Canadian cut points for low ALMI^{3 (link)} that define sarcopenia were applied: less than 7.30 kg/m² for male individuals, and less than 5.42 kg/m² for female individuals. Body fat percentage was calculated as fat mass (kg) divided by total body weight (kg) multiplied by 100. In the CLSA, DXA contraindications were weight exceeding 204 kg, height exceeding 1.88 m, and exposition to an x-ray with contrast material or participation in a nuclear medicine study within the past 7 days (for accuracy of the measurements). Each DXA body weight was ascertained from weight measured by a scale and only participants with weight agreement were included in analyses.^{3 (link)}