Accelerated Anthropometric Ageing Links Loss of Physical Function and Lower Extremity Body Mass

Ageing is associated with anthropometric changes that have been linked to functional limitations and disease risk. However, previous work is limited to a few anthropometric measures, such as body mass index or waist-to-height ratio. Current imaging technology allows a rapid, burden-free and simultaneous assessment of multidimensional anthropometry. What anthropometric measures can predict chronological age and whether the anthropometric age gap (AAG) further predicts health outcomes beyond chronological ageing have not been previously studied. The identification of age-related anthropometric measures could be used clinically to identify individuals who undergo accelerated anthropometric ageing and may be at risk of developing adverse health outcomes.

In 302 Baltimore Longitudinal Study of Aging participants, each participant had 171 body anthropometric measurements collected (mean: 71.7 ± 13.4 years [27-95], 58% women, 30% Black, mean body mass index: 27.4 ± 4.5 kg/m²) using a 3D body scanner (Vitus by Human Solutions GmbH, Kaiserslautern, Germany). We used a LASSO machine learning model to identify anthropometric measures that jointly predicted chronological age after adjusting for sex, race and total body height. We further used covariate-adjusted linear mixed-effects models to examine whether the gap between anthropometric-predicted age and chronological age (AAG) would predict concurrent cognitive/physical functions and body composition, as well as longitudinal changes over the past 20 years (mean follow-up: 13 ± 5 years).

The LASSO regression identified 22 anthropometric measures associated with chronological age (R² = 0.689, mean absolute error = 4.5 years), notably lower thigh girth, waist-to-buttock length and calf girth with older age. Greater AAG was cross-sectionally associated with lower cognitive scores related to motor planning, lower physical function and lower extremity body mass (all p < 0.05). Great AAG was also associated with accelerated declines in sensorimotor functions, including manual dexterity, balance and eccentric muscle strength, and greater loss of lower extremity lean and fat mass (all p < 0.05).

Accelerated anthropometric ageing, involving key age-related measures, is associated with longitudinal declines in sensorimotor and muscle function. Anthropometric features that change with ageing may indicate loss of motor control, mobility and muscle function. Future studies are warranted to understand the mechanistic underpinnings of the associations with health outcomes.