Risk factor | OR (95% CI) | p Value |
Acid exposure >first quartile | 2.408 (0.537 to 10.789) | 0.377 |
Acid exposure >second quartile | 3.179 (1.007 to 10.038) | 0.043 |
Acid exposure >third quartile | 5.678 (2.006 to 16.074) | 0.001 |
Upright acid exposure >first quartile | 2.408 (0.537 to 10.789) | 0.377 |
Upright acid exposure >second quartile | 3.179 (1.007 to 10.038) | 0.043 |
Upright acid exposure >third quartile | 7.609 (2.572 to 22.511) | 0.0002 |
Cut-off points are given at 25% of population intervals for acid. Cut-offs at the first, second and third quartile for acid exposure were 0.6%, 2.2% and 7.1% of time, respectively.