Limited Association between the Total Healthy Eating Index-2015 Score and Cardiovascular Risk Factors in Individuals with Long-Standing Spinal Cord Injury: An Exploratory Study: An Exploratory Study

Abstract

Background: The healthy eating index-2015 (HEI-2015) reflects diet quality in reference to the 2015-2020 Dietary Guidelines for Americans (DGA). Little is known regarding its application in individuals with chronic spinal cord injury (SCI).

Objective: To explore the relationship between diet quality as assessed by the HEI-2015 and cardiovascular risk factors among individuals with chronic SCI.

Design: This is a cross-sectional analysis of baseline data collected from August 2017 through November 2019 for an interventional study that evaluates the effects of a high-protein/low-carbohydrate diet on cardiovascular risk factors in individuals with chronic SCI at the University of Alabama at Birmingham.

Participants/setting: Twenty-four free-living adults with SCI (mean age, 45 ± 12 y; 8F/16M, level of injury: nine cervical, 15 thoracic; mean duration of injury: 20 ± 13 y) were included.

Main outcome measures: Participants underwent a 2-hour oral glucose tolerance test (OGTT) and a dual-energy x-ray absorptiometry scan. Dietary intake was assessed by three, 24-hour multiple-pass dietary recalls to calculate the HEI-2015 using the simple HEI scoring algorithm method.

Data analysis: Multiple linear regression analyses were performed to predict indices of lipid metabolism and glucose homeostasis and C-reactive protein (CRP) from the HEI-2015. Principal component analysis was used to reduce the number of covariates (level of injury, sex, and body fat percentage).

Results: On average, participants' diets were of low quality (HEI-2015, 47.2 ± 10.8). The regression models for fasting glucose (FG), cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and CRP had moderate to large effect sizes (adjusted R² ≥ 13%), suggesting good explanatory abilities of the predictors. Small or limited effect sizes were observed for glucose tolerance, fasting insulin, triglycerides, and Matsuda index (adjusted R² < 13%). The HEI-2015 accounted for a moderate amount of variation in FG (partial omega-squared, ω_P² = 13%). Each 10-point HEI-2015 score increase was associated with a 3.3-mg/dL decrease in FG concentrations. The HEI-2015 accounted for a limited amount of variation in other indices (ω_P² < 5%).

Conclusions: Among participants with SCI, higher conformance to the 2015-2020 DGA was 1) moderately associated with better FG homeostasis; and 2) trivially associated with other cardiovascular risk factors. Because of the small sample size, these conclusions cannot be extrapolated beyond the study sample. Future larger studies are warranted to better understand the relationship between diet quality and cardiovascular disease risks in this population.

Keywords: Cardiovascular health; Dietary patterns; Healthy Eating Index; Multi-pass dietary recalls; Spinal cord injury.