According to a study recently published in Neuromuscular Disorders, body mass index z (BMI-z) scores of patients with Duchenne muscular dystrophy (DMD) increase even before losing ambulation, which warrants early medical interventions to reduce obesity in these patients. 

Through a retrospective multicenter longitudinal study, the authors investigated the BMI-z scores of patients with DMD throughout their transition to ambulation loss and assessed the independent contributions of caloric intake and corticosteroid use. 

There were 159 patients enrolled and analyzed at the first visit; subsequently, the authors developed discontinuous models to study the interactions between BMI-z score, loss of ambulation, caloric intake, and corticosteroid use in further medical visits. 


Continue Reading

Read more about DMD complications

At the first visit, overweight and obesity were present in 44% and 51% of patients in the ambulant and nonambulant groups, respectively. In the nonambulant group, excessive caloric intake and corticosteroids were significantly associated with higher BMI-z scores. 

Longitudinal analyses in ambulant patients showed an increase in BMI-z scores while transitioning to the nonambulatory phase, and interestingly, caloric intake and corticosteroid use were not associated with BMI-z scores.

“We hypothesize that if the daily caloric intake is restricted earlier, possibly from the moment the diagnosis is known, or when patients reach their plateau phase, especially when starting corticosteroids, the onset of overweight and obesity can be prevented,” the authors wrote.

The authors recognized several limitations to their study, including the use of BMI-z for estimating obesity prevalence, the use of 2 different height measurements, the retrospective nature of the study, possible inaccuracies in the measurement or reporting of anthropometric measures, and the use of a 48-hour recall procedure for estimating caloric intake.

“Notwithstanding the limitations of our study, the average increase of BMI-z course which starts already before the actual loss of ambulation is evident. We hypothesize multiple factors may be of influence,” the authors said. Those factors include a decrease in physical activity and progressive replacement of muscle tissue with fibrosis and fat; still, further studies are required to clarify these hypotheses. 

“Obesity is a common problem in patients with DMD. This study showed that even a year before losing ambulation, BMI-z scores increased. Therefore, preventive measures are needed before this time frame,” the authors stated. “Earlier intervention in caloric intake may help to prevent obesity. Besides, stimulation of (adjusted or supported) physical activities during all disease stages can additionally prevent overweight and obesity in the later disease stages.”

Reference

Houwen-van Opstal SLS, Rodwell L, Daalmeyer A, et al. BMI-z scores of boys with Duchenne muscular dystrophy already begin to increase before losing ambulation: a longitudinal exploration of BMI, corticosteroids and caloric intakeNeuromuscul Disord. Published online February 9, 2022. doi:10.1016/j.nmd.2022.01.011