Inflammatory potential of diet and risk of mortality in normal-weight adults with central obesity

Abstract

Background & aims: Inflammatory potential of diet may contribute to poor health outcomes in individuals with metabolic disorders. In a representative sample of the U.S. population, we investigated the association between consuming a pro-inflammatory diet and mortality risk in adults with normal range of body mass index (BMI) but with central obesity.

Methods: This prospective cohort study included 3521 adults 20-90 years of age with normal BMI who participated in the National Health and Nutrition Examination Survey III, 1988-1994 and did not have a history of cardiovascular disease (CVD) or cancer and did not change their dietary intake in the year preceding baseline measurements. Mortality from all causes, CVD, and cancer was ascertained from the National Death Index. Normal-weight central obesity (NWCO, n = 1777) was defined as those with BMI 18.5 to <25 kg/m² and waist-to-hip ratio (WHR) ≥0.85 in women and ≥0.90 in men. Severe central obesity was defined as WHR ≥0.92 in women and ≥1.00 in men. The dietary inflammatory index (DII®) was computed based on baseline dietary intake using 24-h dietary recalls, and associations with mortality were estimated using multivariable Cox proportional hazards regression.

Results: In individuals with NWCO, DII score (i.e., more pro-inflammatory diet) was associated with increased risk of CVD mortality (HR_{T3 vs T1}, 1.89 [95% CI, 1.01-3.53], P trend = 0.04; HR _{1 SD increase} 1.29 [95% CI, 1.06-1.57]). This association was stronger with more severe central obesity (HR_{T3 vs T1}, 2.79 [95% CI, 1.10-7.03], P trend = 0.03; HR _{1 SD increase} 1.52 [95% CI, 1.05-2.21]). DII score was not associated with increased risk of mortality in normal-weight individuals without central obesity or with risk of cancer mortality in either group.

Conclusion: Among individuals in the normal-weight range of BMI, a pro-inflammatory diet assessed by high DII scores was associated with increased risk of CVD mortality in those with central obesity.

Keywords: Body mass index; Dietary inflammatory index; Mortality; National Health and Nutrition Examination Survey; Normal-weight central obesity; Waist-to-hip ratio.