a Odds ratio calculated without consideration of possible confounders (ratio of exposed to unexposed cases divided by the ratio of exposed to unexposed controls).
b 95% confidence intervals for the odds ratio calculated without consideration of possible confounders.
c Includes all factors considered as potential confounders whether or not statistical adjustments were made for them.
d VHCC, very high current configuration.
e OHCC, ordinary high current configuration.
f OLCC, ordinary low current configuration.
g End pole, very low current configuration.