Wilens and colleagues (2008) studied the association between bipolar disorder and substance abuse. In their study, they reported at a 95% CI that "bipolar disorder was associated with an age-adjusted risk for ... alcohol abuse (7.66[2.20, 26.7]), drug abuse (18.5[2.46, 139.10]), dependence (12.1[1.54, 95.50]) ... and cigarette smoking (12.3[2.83, 53.69])" (p. 188). To clarify, the estimates for their study were reported as follows: point estimate [lower confidence limit, upper confidence limit].
(a) Which risk factor was associated with the least variability?
(b) Which risk factor was associated with the most variability?