Abstract Body (Do not enter title and authors here): Introduction: Diet is multidimensional encompassing the quantity, quality, and timing of food intake. Diet quality and chrononutrition metrics have been independently linked to cardiometabolic risk factors, but their interplay in mortality risk has not been evaluated.
Research Question: To evaluate independent and joint associations of diet quality and eating timing with all-cause and cardiovascular (CV) mortality in a nationally representative US cohort.
Methods: Participants were 29,357 adults (mean age 48y, 51% female, 11% Black, 13% Hispanic, 69% White) from the 2003-2018 National Health and Nutrition Examination Survey. A diet quality score was computed per the AHA’s Life’s Essential 8 (LE8) guidelines. Eating timing metrics were estimated from two baseline 24-hour dietary recalls. A data driven approach was used to create a novel eating pattern construct combining diet quality and eating timing metrics predictive of mortality risk. Multivariable Cox proportional hazards models examined associations of diet quality, eating timing, and the novel hybrid construct with mortality in the overall sample and by BMI.
Results: There were 4,271 deaths (1,314 CV deaths). A high vs low LE8 diet score was associated with 30% and 37% lower all-cause and CV mortality risk, respectively (p-trend<0.001) (Figure 1). Among chrononutrition metrics, breakfast timing emerged as the sole significant predictor of mortality risk in the overall sample; those with breakfast intake <10:00 vs. ≥10:00AM had 21% and 25% lower all-cause and CV mortality risk, respectively. Notably, high diet quality combined with earlier breakfast timing more strongly predicted mortality risk than either construct alone; having a high LE8 diet score and breakfast timing <10AM vs. a low LE8 diet score and breakfast timing ≥10:00AM was associated with 56% lower all-cause and CV mortality risk. In analyses stratified by BMI, associations of the LE8 diet score, breakfast timing, and novel hybrid construct were stronger among participants without obesity (Figures 2 and 3); the hybrid construct demonstrated excellent discriminative performance that was significantly improved from the LE8 diet construct (C-statistic: 0.865, p-value=0.031).
Conclusions: Higher diet quality combined with earlier breakfast timing predicted lower mortality risk in US adults, particularly those without obesity, highlighting that addressing both diet quality and eating timing may enhance primordial prevention efforts.