Blood and Other Measurements

Demographic characteristics, smoking status, physical activity, medical history, and medication use (including aspirin, diabetes mellitus medications, antihypertensive medications, and lipid‐lowering medications) were collected through standardized questionnaires at the MESA baseline exam. Level of education was defined as <high school, some college, or college/graduate/professional school. Physical activity was estimated as the total amount of intentional exercise performed in a usual week and measured in metabolic equivalent task (MET)–minutes per week. Smoking status was categorized into never, former, or current smoker.

Physical examination variables (height, weight, blood pressure [BP], etc) were assessed by trained staff using standard MESA procedures.21 Body mass index (BMI) was calculated as weight (kg)/height (m²). After a 5‐minute rest, BP was measured 3 times in the seated position using a Dinamap model Pro 100 automated oscillometric sphygmomanometer (Critikon, Tampa, FL) with the average of the last 2 measurements used as the measure of BP.

Before the exam, participants were instructed to fast for 12 hours and refrain from smoking or strenuous exercise. Blood samples were drawn and stored at −80°C. Blood lipid variables were measured by standard chemical methods. C‐reactive protein (CRP) was measured by a high‐sensitivity assay (N High‐Sensitivity C‐reactive protein; Dade Behring, Deerfield, IL). Homocysteine was measured by fluorescence polarization immunoassay with an IMx Analyzer (IMx Homocysteine Assay; Axis Biochemicals ASA, Oslo, Norway).

Diabetes mellitus was classified as having a fasting blood glucose ≥126 mg/dL and/or the self‐reported history of a physician diagnosis of diabetes mellitus, or the use of diabetes mellitus medications. Hypertension was diagnosed as systolic BP ≥140 mm Hg, diastolic BP ≥90 mm Hg, or use of antihypertensive medications. eGFR was calculated based on the Modification of Diet in Renal Disease (MDRD) equation.27