Association between serum phosphate levels within the normal range and all-cause mortality among US adults

Abstract Introduction Hyperphosphatemia is associated with increased mortality in chronic kidney disease (CKD), but the clinical relevance of variation within the normal serum phosphate range remains unclear. This study evaluated the association between higher-normal serum phosphate levels within the normal range and all-cause mortality among US adults. Methods We conducted a cohort study using data from 15 848 individuals aged ≥20 years with serum phosphate levels between 2.5 and 4.5 mg/dL from the Third National Health and Nutrition Examination Survey (1988-1994) linked to mortality data ascertained by the National Center for Health Statistics with the National Death Index through December 2019. Baseline serum phosphate was the exposure. Participants were categorized into lower-normal (2.5 mg/dL to