Table 1.

Clinical and demographic characteristics of the 72 boilermaker construction worker participants

Observation hours		2993
Arrhythmia events
Ventricular (beats/hour)
	Mean (SD)	14 (69)
	Min, Med, Max	0, 0, 877
Supraventricular (beats/hour)
	Mean (SD)	1 (4)
	Min, Med, Max	0, 0, 92
General*
Male	n (%)	72 (100)
Age (yrs)	Mean (SD)	38 (11)
	Range	19 – 60
Current smoker		31 (43)
Years as a boilermaker	Mean (SD)	10 (12)
	Range	0 – 40
Diagnoses†	n (%)
Cardiovascular
Angina pectoris		1 (1)
Ischemic heart disease		3 (4)
Myocardial infarction		4 (6)
Hypertension		17 (24)
Respiratory
Chronic bronchitis		9 (13)
Asthma		5 (7)

^*at first enrollment

^†at least once during monitoring