Objectives Loss of fat mass (FM) in motor neurone disease (MND) is common and could impact disease progression. Thus, accurate predictions of FM in MND could inform strategies to manage body weight throughout disease course. The aim of this study was to determine whether anthropometric measurements of body mass index (BMI) and body adiposity index (BAI) are accurate predictors of FM in MND patients.
Methods BMI, BAI and percentage FM (determined by air displacement plethesmography (ADP)) were measured in control (n=46) and MND (n=42) study participants.
Results BMI and BAI correlated significantly with FM (p<0.01). Bland Altman analysis showed that BMI and BAI overestimated FM in MND (mean bias of 8.59 for BMI comparisons and 8.47 for BAI comparisons). In longitudinally assessed MND participants (n=23; 6 month assessment interval), a change in BMI (r2=0.61, p<0.01) but not BAI (r2=0.07, p<0.24), correlated significantly with a change in FM.
Conclusions Results from this study suggest that a single measurement of BAI and BMI is likely to overestimate FM in MND. Importantly, longitudinal assessment of BMI in MND patients could be used as an indicator of change in FM over time. Knowledge of limitations and strengths in using BMI and BAI could inform nutritional and dietary strategies to manage body weight in MND.