BACKGROUND:

From 1971-1991 the Occupational Health Service of Los Angeles Country measured physical fitness and other CHD risk factors (including physical activity, anthropometric measures, blood pressure, smoking, family history of CHD, and levels of total cholesterol, uric acid, and glucose) in Los Angeles County firefighters at application and routine intervals (approximately every three years). The entire cohort of 3403 firefighters is now followed for mortality up to 1996.

DESIGN NARRATIVE:

The entire cohort of 3,403 firefighers is followed up to 1996 in this longitudinal study. The investigators are using a variety of tracing sources, including the National Death Index, and obtaining death certificates to determine date and cause of death. Cohort data will be analyzed to address the following aims: (1) To provide a longitudinal description of and determine the interrelationships among physical fitness, physical activity, and other measured risk factors; (2) to determine whether levels of physical fitness are related, independently of other known and measured risk factors, CHD and all-cause mortality; (3) To determine whether there is a gradient of decreasing CHD risk with increasing levels of physical fitness, or whether there appears to be some threshold of physical fitness, above which CHD risk stabilizes; (4) To determine whether the relationship between physical fitness and CHD and all-cause mortality varies by such cardiovascular risk factors as age, cholesterol levels, blood pressure, smoking, and obesity.