Table 1

Demographics and characteristics for the 48 study participants

Individual characteristicsNPer cent
Smoking status (current smoker)*1940
Other characteristics
 Time of ECG (AM)†1838
 Season of ECG (Winter)‡3369
 Heart problems§510
Age at start of study 2010 (years)4012
Number of years as a boilermakers (years)99
Last weld day before study (days)4451
  • *Current smokers versus non-smokers and previous smokers.

  • †Morning (AM) versus afternoon (PM).

  • ‡Winter versus summer.

  • §Heart problems include reported previous history of arrhythmia, cardiac sinus problems or palpitations.