Body mass indices and skeletal size in 394 Canadians aged 55-86 years

Demispan (finger web to midline) is the preferred index of stature in the study of the elderly where height is unreliable because of age-related loss or distortion. As a consequence, two alternative mass indices, Demiquet (male mass. demispan-2) and Mindex (female mass. demispan-1), have been proposed for use in the elderly, in place of body mass index calculated from height, which might be suspect. These gender-specific indices reflect the squared and linear relationship of height to mass in men and women respectively. To assess the independence of Demiquet and Mindex from stature and the reliability of demispan, height, demispan (second fingerweb to midline), and mass were recorded in a random sample of independent Canadian men (182) and women (212) aged 55-86 years. Both Demiquet and Mindex were highly correlated with mass, r = 0.81 (p = 0.001) and r = 0.96 (p = 0.001), respectively. In both gender groups these mass indices were independent of height and demispan. The demispan within- and between-observer errors were small -0.04(-0.16 to 0.08)cm and -0.09(-0.22 to 0.03) cm and the between-observer intraclass correlation estimate of reliability was 0.96 (lower-bound one-sided 95% CI 0.90). Demispan is a reliable and reproducible measure of stature in the elderly. Demiquet and Mindex are useful mass indices, independent of stature and suitable for use in the study of the elderly where the use of mass indices based on height may be questionable.