Baseline Characteristics
Among 485 US career firefighters enrolled in this trial, 458 (94.4%) were male, and the mean (SD) age was 47 (7.5) years. A total of 69 participants were Black (14.3%), 401 were White (82.9%), and 14 were another race or ethnicity (including American Indian or Alaska Native, Asian, Hispanic, or Native Hawaiian or Other Pacific Islander; 2.9%). After exclusion of 1 participant for total daily energy intake levels beyond predefined limits, 484 firefighters were included in the primary analysis (