Monetary diet cost is positively associated with diet quality and obesity: an analysis of school-aged children in Southwest China

Background Little is known about the relationships between diet cost, dietary intake and obesity in Chinese populations. This study explored how diet cost was related to diet quality and obesity among school-aged children in Southwest China. Methods Data from a cross-sectional study was analysed. Diet cost was estimated based on dietary intake assessed with 24-h dietary recalls and retail food prices. Diet quality was measured using the Chinese Children Dietary Index. Body height, weight, waist circumference and skinfold thicknesses were measured, and their body mass index standard deviation score (BMISDS), waist-to-height ratio (WHtR), fat mass index (FMI) and fat-free mass index (FFMI) were calculated. Multivariate regression models were used to explore the relevance of diet cost to diet quality and obesity. Results After adjustment for potential confounders, a positive association was observed between diet quality and energy-adjusted diet cost (beta = 0.143, 95% confidence interval, CI: 0.014-0.285, Pfor-trend = 0.0006). Energy-adjusted diet cost also showed a positive association with FMI (beta = 0.0354, 95% CI: 0.0001-0.0709, Pfor-trend = 0.01), BMISDS (beta = 0.0200, 95% CI: 0.0006-0.0394, Pfor-trend = 0.002) and WHtR (beta = 0.0010, 95% CI: 0.0003-0.0017, Pfor-trend = 0.02). Conclusions Energy-adjusted diet cost was independently and positively associated with diet quality and obesity among Chinese school-aged children.