Perimenopausal women Inclusion criteria Age ≥40 years Female gender Between 1 and 6 menstrual cycles in the last 12 months GFR >40 mL/min/1.73 m2 Hematocrit ≥ 35% Willing to not donate blood during study 2 or more major risk factors1 (study population) or 0 or 1 risk factors (controls) Exclusion criteria Inability/unwillingness to provide informed consent Contraindication to MRI2 Known abnormality of iron metabolism3 Bleeding disorder or bleeding event in the past 6 months Known atherosclerotic heart or peripheral vascular disease Pregnancy Use of hormone therapy Active infection4 NOTES: 1-risk factors include hypertension, diabetes, smoking, and hyperlipidemia. 2-presence of ferromagnetic foreign body, aneurysm clip, any MRincompatible implant, inability to fit in MRI scanner; 3-examples include hereditary hemochromatosis, iron deficiency, paroxysmal nocturnal hemoglobinuria, hemosiderosis for any reason, atransferrinemia; 4-active infections include conditions like urinary tract infection, pneumonia, and viral illnesses.

Table 1: Inclusion and exclusion criteria.