... The overall characteristics of the included studies are reported in Supplementary Table 4: fourteen employed a cohort design [17, 21, 40, 42, 43, 46, 48, 51-54, 58-60, 62, 65], thirteen were cross-sectional [18, 20, 38, 39, 41, 44, 45, 47, 49, 50, 55-57, 61, 63, 64] and one was casecontrol [37]. These studies were conducted between 2007 and 2024, and spanned multiple nations: United States [17,21,37,40,42,46,54,60,61,65], United Kingdom [59], China [20,43,44,50,58,64], Iran [18,41,47,49], Taiwan [38,45,48,56], the Netherlands [53], Spain [51,52,62], Croatia [57], Korea [55], Japan [63] and Thailand [39]. The maximally adjusted RR specific to each study was recorded for a total of 786,216 individuals across the included publications and was subsequently pooled for a meta-analysis aimed at evaluating the relationship between UPFs and CKD risk. ...