Dietary inflammatory potential and risk of mortality in metabolically healthy and unhealthy phenotypes among overweight and obese U.S. adults

Abstract

Background and Aims

This study was designed to investigate the association between the dietary inflammatory index (DII ^®) scores, metabolic phenotypes, and risk of mortality risk in overweight/obese individuals from a representative sample of the U.S. population.

Methods

Data from 3733 overweight/obese adults (BMI≥25kg/m ²) aged 20–90 years from the National Health and Nutrition Examination Survey III, 1988–1994 were analyzed; these participants were followed for mortality through December 31, 2011. DII scores were computed based on baseline dietary intake using 24-hour dietary recalls. Metabolically unhealthy status was defined as having 2 or more of these metabolic abnormalities: high glucose, insulin resistance, elevated blood pressure, triglycerides, C-reactive protein levels, or low high-density lipoprotein-cholesterol values.

Results

In metabolically unhealthy overweight/obese (MUO) individuals, DII score was associated with increased risk of all-cause mortality (HR _{Tertile 3 vs Tertile 1} 1.44; 95% CI 1.11–1.86 P _trend=0.008; HR _{1SD increase} 1.08; 95% CI 0.99–1.18). Additionally, a stronger association with cardiovascular mortality was observed (HR _{T3 vs T1} 3.29; 95% CI 2.01–5.37 P _trend<0.001; HR _{1SD increase} 1.40; 95% CI 1.18–1.66), after adjusting for potential confounders. Furthermore, when analyses were restricted to obese individuals (BMI≥30 kg/m ²), the association was more pronounced, especially for cardiovascular mortality (HR _{T3 vs T1} 5.55; 95% CI 2.11–14.57 P _trend=0.006; HR _{1SD increase} 1.74; 95% CI 1.21–2.50). No association was observed between DII score and risk of mortality in individuals with metabolically healthy overweight/obese (MHO) phenotype, or for cancer mortality in either MHO or MUO phenotype.

Conclusions

A pro-inflammatory diet appears to increase risk of all-cause and cardiovascular mortality in the MUO phenotype, but not among the MHO phenotype.