Background: Most diet quality indices (DQIs) lack universal applicability and rely on detailed, often inaccessible nutrient composition data. In contrast, the Global Diet Quality Score (GDQS) measures diet quality using only food items, without population-specific adaptations. We aim to evaluate the association between the GDQS and cardiovascular disease (CVD) risk relative to other DQIs in U.S. adults. Hypothesis: Higher GDQS is associated with lower CVD risk, with magnitude and precision comparable to other DQIs. Methods: Prospective cohort data from the Nurses’ Health Study I (NHS I), II (NHS II), and Health Professionals Follow-up Study (HPFS) were used. Dietary intake was assessed every 2 to 4 years (NHS I: 1986-2010, NHS II: 1991-2015, HPFS: 1986-2018) using validated food-frequency questionnaires; medical, lifestyle, and anthropometric data were updated biennially. The GDQS, Alternative Healthy Eating Index (AHEI-2010), Adapted Mediterranean Diet Score (aMed), Dietary Approaches to Stop Hypertension (DASH) index, and Planetary Health Diet Index (PHDI) were computed. Incident CVD, coronary heart disease (CHD), and stroke were identified via medical and mortality records. Participants with baseline CVD, cancer, or implausible energy intake were excluded. Multivariable-adjusted Cox proportional hazard models estimated hazard ratios (HR; 95% CI) of incident outcomes per 1-standard deviation SD increase in continuous DQIs and across their quintiles. DQIs were standardized (mean=0; SD=1) for comparison. Estimates from the three cohorts were combined using fixed-effects meta-analysis. Result: During a median follow-up of 24 years (IQR: 8 years), 16,055 cases were identified among 200,823 U.S. adults. Each SD increase in GDQS was associated with a lower risk of total CVD, CHD, and stroke. The magnitude of associations strengthened progressively across increasing GDQS quintiles. The GDQS was similarly or more strongly associated with CVD risk compared to other DQIs, with quintile-specific 95% CIs overlapping those of the AHEI-2010, which was specifically designed for CVD assessment (Figure 1). Conclusion: The GDQS was associated with lower CVD risk and displayed magnitude and precision comparable to or stronger than other, more complex DQIs, supporting its utility for CVD risk assessment. These findings warrant further evaluation of the GDQS in other population settings.
Espinosa et al. (Tue,) studied this question.