The association between dietary factors and body weight and composition in boys with Duchenne muscular dystrophy

Background Duchenne muscular dystrophy (DMD) is a X-linked neuromuscular disorder. Boys with DMD have high rates of obesity, although little is known about dietary factors that may contribute to weight gain in this population. The present study aimed to explore the relationship between dietary factors, body mass index (BMI) z-score, body composition and motor function and to describe dietary intake in boys with DMD. Methods A cross-sectional analysis of 3-day food diaries from ambulant and steroid treated boys with DMD aged 5-13 years was conducted. Correlation analysis explored the relationship between dietary factors, BMI z-score, fat mass percentage (FM%) and lean mass percentage (LM%). Results The median age was 8.5 years (interquartile range [IQR] = 7.2-10.5 years). Median energy kg(-1) day(-1) in those within a healthy weight range (n = 11) was 316 kJ kg(-1) day(-1) (IQR = 276-355 kJ kg(-1) day(-1)) and greater than estimated requirements and, for those above a healthy weight (n = 26), energy intake was 185 kJ kg(-1) day(-1) (IQR = 143-214 kJ kg(-1) day(-1)) and lower than estimated requirements. Energy kg(-1) day(-1) was negatively associated with BMI z-score (r = -0. 650) and FM% (r = -0.817) but positively associated with LM% (r = 0.805; all analyses p = <0.01). Younger age was associated (r = -0.609 p = <0.01) with a higher energy kg(-1) day(-1). For all participants, vegetable, grains, meat/alternatives and dairy intakes were sub-optimal. Conclusions Younger boys with DMD within a healthy weight range are overconsuming energy dense nutrient poor foods. A focus on improving diet quality during early childhood may prove to be a useful strategy for reducing excess weight gain and supporting healthier eating habits in this vulnerable clinical population.