Low mid-upper arm circumference, calf circumference, and body mass index and mortality in older persons

Abstract

Background: Low body mass index is a general measure of thinness. However, its measurement can be cumbersome in older persons and other simple anthropometric measures may be more strongly associated with mortality. Therefore, associations of low mid-upper arm circumference, calf circumference, and body mass index with mortality were examined in older persons.

Methods: Data of the Longitudinal Aging Study Amsterdam, a population-based cohort study in the Netherlands, were used. The present study included community-dwelling persons 65 years and older in 1992-1993 (n = 1,667), who were followed until 2007 for their vital status. Associations between anthropometric measures and 15-year mortality were examined by spline regression models and, below the nadir, Cox regression models, transforming all measures to sex-specific Z scores.

Results: Mortality rates were 599 of 826 (73%) in men and 479 of 841 (57%) in women. Below the nadir, the hazard ratio of mortality per 1 standard deviation lower mid-upper arm circumference was 1.79 (95% confidence interval, 1.48-2.16) in men and 2.26 (1.71-3.00) in women. For calf circumference, the hazard ratio was 1.45 (1.22-1.71) in men and 1.30 (1.15-1.48) in women and for body mass index 1.38 (1.17-1.61) in men and 1.56 (1.10-2.21) in women. Excluding deaths within the first 3 years after baseline did not change these associations. Excluding those with a smoking history, obstructive lung disease, or cancer attenuated the associations of calf circumference (men) and body mass index (women).

Conclusions: Based on the stronger association with mortality and given a more easy assessment in older persons, mid-upper arm circumference seems a more feasible and valid anthropometric measure of thinness than body mass index in older men and women.

Figure 1.

Dose–response associations between anthropometric measures and 15-year mortality among men, the Longitudinal Aging Study Amsterdam, 1992–1993. The left column shows the hazard ratios plotted on a logarithmic scale in the total study sample, the middle after excluding all deaths occurring within first 3 years after baseline, and the right column after excluding current and former smokers, obstructive lung disease (25), or cancer. The associations found in the total study sample (left) are superimposed in black on the other figures. Dotted lines represent the 95% confidence intervals, which converge to the median reference value (hazard ratio = 1) because standard errors become infinitely small when approaching the reference point. Rug plots are shown along the x-axes of the graphs to depict the distribution of the anthropometric measures.

Figure 2.

Dose–response associations between anthropometric measures and 15-year mortality among women, the Longitudinal Aging Study Amsterdam, 1992–1993. The left column shows the hazard ratios plotted on a logarithmic scale in the total study sample, the middle after excluding all deaths occurring within first 3 years after baseline, and the right column after excluding current and former smokers, obstructive lung disease (25), or cancer. The associations found in the total study sample (left) are superimposed in black on the other figures. Dotted lines represent the 95% confidence intervals, which converge to the median reference value (hazard ratio = 1) because standard errors become infinitely small when approaching the reference point. Rug plots are shown along the x-axes of the graphs to depict the distribution of the anthropometric measures.