The Dietary Inflammatory Index and Sarcopenia in Older Adults in Four Chinese Provinces: A Cross-Sectional Study

Background: Sarcopenia associated with aging severely affects the quality of life of the elderly; diets have been shown to elicit an inflammatory response in the body, and diets that promote inflammation may lead to damage to muscles. The Dietary Inflammatory Index (DII) has been developed to quantify the inflammatory potential of individual diets. Therefore, this study aimed to investigate the association between the DII, sarcopenia and its components in elderly Chinese people. Methods: In this study, data were obtained from the China Nutrition Improvement Strategies and Applications for the Elderly Research Programme. An assessment of sarcopenia was carried out according to the Asian Working Group on Sarcopenia's (AWGS2019) criteria. The DII was calculated using food intake data obtained using the FFQ method, and then the quartile method was used to categorize the subjects into four groups. Multifactor logistic regression was conducted to examine the associations between DII, sarcopenia and its components. Results: This study included 993 subjects over the age of 65, and the prevalence of sarcopenia was 20.2%. The mean DII score of the study population was 0.99 ± 0.1. After adjusting for the confounders age, gender, marital status, and educational level, the risk of sarcopenia was 1.66 times higher in group Q4 than in group Q1 (p-trend < 0.05). However, this relationship is not statistically significant when other more confounding factors are added. Nevertheless, when further analyzing the relationship between DII and sarcopenia components, it was found that after adjusting the model, a higher DII was associated with a risk of muscle strength loss (OR = 1.65, p-trend < 0.05). Conclusions: Higher DII scores increase the risk of muscle strength loss in older adults. By guiding older adults to adopt a more anti-inflammatory diet, muscle health can be improved in terms of increased muscle strength. Further cohort or interventional studies are necessary to validate our findings.