Table 1

Blood lead levels (BLLs) for the first and final round of testing and t-test results for differences by gender and job classification for log-transformed mean values

N (%)Mean ageGM BLL first round95% CIGM BLL final round*95% CIPer cent change (first vs final)P value (first vs final)†
Males41 (67)28.230.323.1 to 39.819.515.7 to 24.2−36<0.001
Females20 (33)20.934.429.1 to 40.726.522.6 to 31.0−230.001
Miners47 (77)26.028.523.0 to 35.320.116.7 to 24.3−29<0.001
Ore processors14 (23)24.944.730.6 to 65.227.020.9 to 35.0−400.002
Total participants 61 25.8 31.6 26.1 to 38.1 21.5 18.4 to 25.2 32 < 0.001
Total (1st–7th testing round) 58 25.5 31.4 25.7 to 38.3 21.4 18.2 to 25.2 32 < 0.001
  • *Final round indicates the 7th round of testing for all except for three individuals who were last tested in the 6th round.

  • †Significance tests were conducted based on logged values due to non-normal distribution.

  • GM, geometric mean.