Plant-based diet quality, fat mass, and cardiovascular disease: a mediation analysis of mid-aged adults in the UK Biobank
Year: 2025
Type: article
Abstract: Evidence supports plant-based dietary patterns for preventing cardiovascular diseases (CVD)(1). Fat mass is a strong predictor of CVD(2), however it’s unclear whether this mediates the relationship between plant-based dietary patterns and CVD. Hence, the aim of this study was to determine if longitudinal associations between plant-based dietary patterns and incidence of CVD events, CVD mortality and all-cause mortality are mediated by fat mass in mid-life. Dietary data (Oxford WebQ) from 14,247 adults (median 56 years [IQR 49–61]) in the UK Biobank cohort study were used to derive diet quality index scores for an overall plant-based diet (PDI), a healthy plant-based diet (hPDI), and a less healthy plant-based diet (uPDI). Health registries and national records provided CVD event and mortality data. Percentage fat mass was measured by dual X-ray absorptiometry. Cox proportional hazard ratios (95% CI) identified associations between each diet quality index and CVD events, CVD mortality or all-cause mortality. Regression-based mediation analysis was used to identify the direct effect (plant-based diet quality indices on CVD mortality, CVD events, or all-cause mortality), and the indirect effect, which was mediated by fat mass. New CVD events (n = 364), CVD mortality (n = 52) and all-cause mortality (n = 220) were identified with mean follow up of 11.6 (SD ± 0.4) years for CVD events, and 11.5 (SD ± 0.7) years for mortality. The mean score for PDI was 50.5 (SD ± 5.9), hPDI 52.8 (SD ± 7.2), and uPDI 54.0 (SD ± 6.8). The PDI and hPDI were inversely associated with fat mass, and the uPDI was positively associated with fat mass (p < 0.001). There was no association between the diet quality indices and health outcomes, with (direct effect) or without (total effect) the fat mass mediator for males and females (p ≥ 0.1). Fat mass was associated with risk of mortality in some models, after controlling for the indices, such as a lower risk of all-cause mortality after controlling for the hPDI (p < 0.1). There was a significant negative indirect effect of hPDI on CVD mortality via fat mass for females only (observed coefficient 0.81; 95% CI 0.60–0.99). Overall, there was limited evidence of a mediating effect from fat mass in the association between plant-based dietary patterns and incidence of CVD events, CVD mortality and all-cause mortality. Studies with larger samples and longer follow up are needed to determine whether the mediating effect of fat mass on hPDI and CVD mortality in females is reproducible.
Language: English
Topic: Nutritional Studies and Diet
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4410566261