Diet quality as measured by the Diet Quality Index-International is associated with prospective changes in body fat among Canadian children.

OBJECTIVE: To quantify the association of dietary quality with prospective changes in adiposity.

DESIGN: Children participating in the QUALITY (QUebec Adipose and Lifestyle InvesTigation in Youth) study underwent examination at baseline and at 2-year follow-up. Dietary quality was assessed by the Diet Quality Index-International (DQII) using three non-consecutive 24 h diet recalls at baseline. The DQII has four main categories: dietary adequacy, variety, moderation and overall balance. Fat mass index (FMI; [fat mass (kg)]/[height (m)]2), central FMI (CFMI; [trunk fat mass (kg)]/[height (m)]2), percentage body fat (%BF; [total fat mass (kg)]/[total mass (kg)]) and percentage central BF (%CBF; [trunk fat mass (kg)]/[total mass (kg)]) were assessed through dual-energy X-ray absorptiometry.

SETTING: Children were selected from schools in the greater Montreal, Sherbrooke and Quebec City metropolitan areas between 2005 and 2008, Quebec, Canada.

SUBJECTS: A total of 546 children aged 8-10 years, including 244 girls and 302 boys.

RESULTS: Regression analysis adjusting for age, sex, energy intake, physical activity and Tanner stage revealed that every 10-unit improvement in overall DQII score was associated with lower gain in CFMI (β=-0·08; 95 % CI -0·17, -0·003) and %BF (β=-0·55; 95 % CI -1·08, -0·02). Each unit improvement in dietary adequacy score was associated with lower gain in FMI (β=-0·05; 95 % CI -0·08, -0·008), CFMI (β=-0·03; 95 % CI -0·05, -0·007), %BF (β=-0·15; 95 % CI -0·28, -0·03) and %CBF (β=-0·09; 95 % CI -0·15, -0·02).

CONCLUSIONS: Promotion of dietary quality and adequacy may reduce weight gain in childhood and prevent chronic diseases later in life.