The association between Dietary Inflammatory Index and disability in older adults

Background & aims: The impact of the potential inflammatory effect of diet on disability has not been adequately investigated. We examined the association of Dietary Inflammatory Index (DII) on disability in older American adults and detected if these associations differed by stratification across sex and body mass index (BMI) level. Methods: Data were from the National Health and Nutrition Examination Survey (2007–2016). DII scores were calculated through two 24-h dietary recall interviews. Disability including functional limitations and activities of daily living (ADL) limitations were self-reported. The associations of DII scores on functional limitations and ADL limitations were evaluated by age-sex and multivariable adjusted logistic regression models and further stratification of these associations by sex and BMI level. Restricted cubic splines analyses were used to assess the shapes of these associations. Results: A total of 6893 participants aged 60 years and above were eligible for this study. DII was related to higher odds of functional limitations. Compared to the lowest quintile of DII scores, the odds ratio (OR) for participants in the second, third, fourth, and highest quintile were 1.61 (95%CI:1.20–2.15), 1.42(95%CI:1.09–1.85), 1.51 (95%CI:1.09–2.09) and 1.97 (95%CI:1.37–2.82) for functional limitations (P-trend = 0.003). The positive associations between DII scores and functional limitations were observed both in men and women. The corresponding ORs (95%CI) across all quintiles were 1.68(1.07–2.66), 1.54(1.06–2.25), 2.03(1.18–3.47), 2.11(1.19–3.74) in men (P-trend = 0.008) and 1.52(1.03–2.27), 1.32(0.86–2.02), 1.24(0.81–1.90), 1.74(1.11–2.73) in women (P-trend = 0.089). In the stratified analyses by BMI level, comparing the lowest quintiles, the corresponding ORs of functional limitations in second, third, fourth, and fifth quintiles were 2.71 (95% CI: 1.57–4.68), 2.39(95% CI: 1.38–4.11), 2.34(95% CI: 1.31–4.19), 2.54(95% CI: 1.25–5.13) in overweight (P-trend = 0.019) and 1.32(95% CI: 0.81–2.15), 1.17(95% CI: 0.71–1.92), 1.33(95% CI: 0.77–2.30), 2.15(95% CI: 1.19–3.87) in obesity (P-trend = 0.032). Conclusions: The results provide evidence of a positive association between DII score and functional limitations in American older adults, especially participants with overweight and obesity.