Planetary Health Diet, Socioeconomic Inequalities, and CKD and Mortality Risk

Key Points Higher planetary health diet score was related to improved kidney function, reduced prevalence and incidence of CKD, and lower all-cause mortality. Higher planetary health diet score was correlated with lower greenhouse gas emission and land use, but with higher water use. Socioeconomic deprivation linked to lower planetary health diet adherence and weakened planetary health diet benefits on cystatin C and all-cause mortality. Background While planetary health diet (PHD) benefits human and environmental health, its effect on CKD under socioeconomic deprivation remains unclear. We investigated the associations between PHD and kidney function, CKD, mortality, and environmental effects, while evaluating the moderating role of socioeconomic deprivation. Methods We included 125,581 UK Biobank and 35,021 National Health and Nutrition Examination Surveys (NHANES) participants. The associations between PHD score, kidney function, CKD, mortality, and environmental impacts were assessed using Cox proportional-hazards model, logistic regression, or multiple linear regression models. Multiplicative interactions between PHD scores and index of multiple deprivation and its domains on these associations were evaluated. Results In the UK Biobank and NHANES, median PHD score was 62.34 (53.74–70.97) and 40.45 (31.38–50.21), respectively. In UK biobank, each one-point higher PHD score was associated with greater eGFR ( β [95% confidence interval], 0.05 [0.04 to 0.05]). Compared with the lowest quartile (Q1) of PHD score, the highest quartile (Q4) was associated with lower CKD (hazard ratio [95% confidence interval], 0.75 [0.69 to 0.81]) and all-cause mortality (0.83 [0.78–0.89]). Similarly, in NHANES participants each one-point higher PHD adherence was associated with greater eGFR (0.06 [0.05–0.08]), lower CKD prevalence (OR Q4 versus Q1 : 0.80 [0.73–0.88]), and lower risk of all-cause mortality (hazard ratio Q4 versus Q1 : 0.85 [0.77–0.93]). Higher PHD score was correlated with lower greenhouse gas emission and land use, but with higher water use. Stronger inverse associations of PHD with cystatin C were observed among individuals with higher health deprivation ( P < 0.01), while stronger inverse associations with all-cause mortality were observed among those with higher employment and living environment deprivation ( P = 0.01). Conclusions PHD was associated with improved kidney health, lower all-cause mortality, greenhouse gas emission, and land use, with strongest health benefits in socioeconomically deprived populations. Our study supports PHD as a strategy for concurrent human and planetary health, highlighting its potential to address health inequities.