Beginning in 1981, NHLBI supplemented the NHANES examination protocol by including questions about history of heart, lung, and blood diseases, and their treatment. The examination also included the Rose questionnaires for angina, myocardial infarction and peripheral vascular disease, 12-lead electrocardiograms, questions about known and suspected risk factors including active and passive smoking, weight history, use of exogenous hormones, family history of heart, lung and blood diseases, and selected aspects of diet, psychosocial characteristics (depression, anxiety, social support, job control and demands, and anger experience and expression), and lifestyle. If feasible, 2-hour ECG Holter monitor records were obtained to identify and classify premature ventricular contractions and to detect episodes of ischemia. Pulmonary function tests were performed using standardized methods and strict quality assurance procedures and the American Thoracic Society-Division of Lung Diseases respiratory disease questionnaires were administered. Waist and hip girth measurements were obtained along with other anthropometric measures. Blood pressure determinations were made in the home as well as in the mobile examination center. Blood tests included lipids and lipoproteins, fibrinogen, hematocrit, white blood cell count, and differentials, fasting and post-challenge insulin and glucose concentrations, and nutritional biochemistries.