Given that serum phosphorus is a risk factor for cognitive decline in CKD and that higher FGF-23—often elevated in the context of higher serum phosphorus—represents a risk factor for cerebral small vessel disease, we hypothesized that mild elevation in serum phosphorus—even when serum phosphorus levels remain within the reference range—may be associated with increased risk of incident dementia. This evidence concerns the gene FGF23 and dementia.