BMI-z scores of boys with Duchenne muscular dystrophy already begin to increase before losing ambulation: a longitudinal exploration of BMI, corticosteroids and caloric intake

•Overweight and obesity are highly prevalent in this study population of DMD patients.•Detailed, longitudinal exploration on the BMI-z course shows an increase around the period of losing ambulation, which starts already before patients become wheelchair bound.•Cross sectionally corticosteroid use was associated with higher BMI-z scores and exceeding the recommended caloric intake was associated with higher BMI in non- ambulatory patients.•Although longitudinal mixed model analysis did not show significant association between BMI-z score and corticosteroid use or caloric intake, explorative analysis of the longitudinal data show that BMI-z increases before caloric intake is adjusted (often from the moment patients become wheelchair bound). Earlier intervention in caloric intake could probably help to prevent obesity. We aimed to investigate BMI-z course in patients with Duchenne muscular dystrophy (DMD) during transition to loss of ambulation, and to explore the contribution of caloric intake and corticosteroid use. A retrospective multicenter longitudinal study was conducted. First, analyses of characteristics at first visit were carried out. Second, discontinuous change models were fitted to explore associations between BMI-z, loss of ambulation, caloric intake and corticosteroid use. 790 visits of 159 patients were collected. Cross sectional first visit analyses showed the presence of overweight and obesity was 44% in the ambulant group and 51% in the non-ambulant group. In the non-ambulatory group, exceeding the recommended caloric intake was associated with higher BMI-z scores (r 0.36, p = 0.04). Patients who were using corticosteroids had significantly higher BMI-z scores compared with patients not using corticosteroids (1.06 and 0.51 respectively, p = 0.02). Longitudinal analyses on patients ambulant at first visit showed an increase in BMI-z score during transition to the non-ambulatory phase. Caloric intake and corticosteroid use were not associated with BMI-z. Transition to the non-ambulatory phase may be crucial in the development of excessive weight gain. Early measures – starting before this time frame – may contribute to reduce development of obesity.