Low muscle strength, BMI in young males predict eventual ALS
In healthy, young males, low muscle strength, body mass index (BMI) and erythrocyte volume fraction predict amyotrophic lateral sclerosis (ALS) later in life, a recent study has shown.
The researchers performed a prospective cohort study on 1,819,817 young males with an average age of 18.3±0.7 years. Over the 46-year follow-up period, 526 participants were diagnosed with ALS. The median age at first diagnosis was 50.0 years.
Baseline BMI was significantly lower in those who eventually developed ALS than in those who did not (21.9±3.0 vs 21.1±2.5 kg/m2; p=0.03). Difference in baseline muscle strength also showed a trend toward significance, wherein low muscle strength was more common in those who developed ALS later in life (p=0.06 for trend).
Mean erythrocyte volume fraction was likewise significantly lower in those who developed ALS than in those who did not (46.4±2.4 percent vs 46.2±2.5 percent; p=0.05).
The same trends were observed in a multivariate logistic regression model adjusted for potential confounders. For instance, BMI (hazard ratio [HR], 0.96; 95 percent CI, 0.93–0.99) remained a significant predictor of eventual ALS. Erythrocyte volume fraction was also significantly correlated with the risk of ALS (HR, 0.96; 0.92–0.998).
Finally, relative to high muscle strength at baseline, low muscle strength was likewise significantly predictive of ALS development later in life (HR, 1.36; 1.01–1.83).
In contrast, there appears to be no correlation between the risk of eventual ALS and erythrocyte sedimentation rate, physical fitness at baseline, parental education or psychiatric disorders.