The relationship between dietary inflammatory index (DII) and muscle mass and strength in Chinese children aged 6-9 years.

BACKGROUND AND OBJECTIVES: The dietary inflammatory index (DII®) is a measure of the overall inflammatory potential of a person's diet. However, there have been no studies looking at the effect of DII on measures of muscle mass and strength. We aimed to examine the association between DII and skeletal muscle mass and strength in Chinese children.

METHODS AND STUDY DESIGN: A total of 466 children aged 6-9 years completed the study. Total body skeletal muscle mass (TSM), appendicular skeletal mass (ASM) and appendicular lean mass (ALM) were determined using Dual-energy X-ray absorptiometry. TSM/Height², TSM/Weight, ASM/Height² and ASM/Weight were calculated. The residual method was applied to compute ALM index (ALMI) adjusted for height and body fat. Hand grip strength was measured using hand dynamometer. DII scores were calculated from a 79-item food frequency questionnaire.

RESULTS: Fully adjusted linear regression models showed a statistically significant negative relationship between DII and ASM, ASM/Height², ASM/Weight, ALMI, TSM, TSM/Height², and TSM/Weight (p: 0.019‒0.014). The analysis of covariance indicated that the percentage differences in the extreme quartiles (Q4 vs Q1) of DII for the above-mentioned measures ranged from -1.04% to -4.36% (p-trend: <0.001‒0.013). When boys and girls were analyzed separately, similar findings were observed for boys but not for girls. No significant associations were detected between DII and hand grip strength.

CONCLUSIONS: DII score was inversely associated with skeletal muscle mass in boys but not in girls aged 6-9 years old. No significant associations were observed between DII and hand grip strength.