Exploring the role of anthropometric measurements to assess nutritional status in amyotrophic lateral sclerosis: a longitudinal prospective cohort study.

Objective: To observe longitudinal correlations between limb anthropometry against weight, BMI and functional decline in patients with amyotrophic lateral sclerosis.

Methods: A longitudinal, prospective, cohort study was undertaken. Four consecutive measurements of weight, height, triceps skinfold thickness (TSF), mid-upper arm (MUAC) and calf circumferences were collected at three-monthly intervals. Fat- and lean body mass were estimated using measurements of TSF and derivations of arm muscle area, respectively. Correlation analyses indicated associations between anthropometric assessments and functional decline (ALSFRS-R). Longitudinal changes were assessed using repeated measures analyses.

Results: Data from 18 participants was analyzed. At enrollment, weight positively correlated with MUAC (n = 17, p = 0.0001), arm muscle area (n = 17, p = 0.04) and calf circumference (n = 17, p < 0.0001). The ALSFRS-R score negatively correlated with weight (n = 17, p = 0.03), MUAC (n = 18, p = 0.01), TSF (n = 18, p = 0.04), and calf circumference (n = 18, p = 0.003). Function significantly declined by a difference of 6.3 points per month (p = 0.009). A positive correlation was observed between the changes in weight and calf circumference over nine months (r = 0.70, p = 0.02, n = 10).

Conclusion: Limb anthropometric measurements may be surrogate indicators of weight and BMI; TSF may be a practical, reliable indicator of fat mass, whilst changes in calf circumference may be alternatively used to monitor changes in nutritional status in the clinic.