Covariate Data

Data on age, sex, education, medication use, smoking, alcohol consumption, physical activity, occupational history, and diet were collected at baseline by trained interviewers using semistructured questionnaires. Medication use was assessed by asking participants about all medications used in the previous 2 wk. Physical activity was classified as exercise for at least 20 min per week for more than half a year, based on information about activity at work and at leisure. Occupation category was measured as the most recent occupation engaged for more than 3 y before retirement. Diet was classified according to usual intakes of major food groups (meats, vegetables, fruits, beans, eggs, and dairy) in the previous 1 y using a simplified food frequency questionnaire. Participants also were asked about previous medical diagnoses and about their family history of specific diseases (limited to first-degree family members and doctor-diagnosed conditions), including CHD.

Standing height and body weight were measured by trained personnel during the baseline physical examination. In addition, each participant’s resting blood pressure [systolic (SBP) and diastolic (DBP)] was measured one time, and average SBP and DBP values were calculated. Fasting blood was drawn for laboratory assays of blood lipids, fasting glucose, and renal function. Hypertension was defined if the measured BP values were  ≥ 140 mmHg for SBP or  ≥ 90 mmHg for DBP, or if the participant self-reported physician diagnosis or use of antihypertensive medications. Hyperlipidemia was defined if total cholesterol was  ≥ 5.72 mmol/L, or triglycerides was  ≥ 1.70 mmol/L, or the participant self-reported physician diagnosis or use of antihyperlipidemia medications. Diabetes was defined if the fasting glucose level was  ≥ 7.0 mmol/L, or the participant self-reported physician diagnosis or use of antidiabetic medications (insulin or oral hypoglycemic agents). We applied the Modification of Diet in Renal Disease equation based on the Chinese patients with chronic kidney disease to calculate estimated glomerular filtration rates (eGFR) (Ma et al. 2006).