an increasing trendP = 0.11
For ever- smoking the OR was 1.18 (95% CI 0.96-1.46), and there was only weak evidence of an increasing trend in relative risks with smoking intensity (x2, = 2.58, P = 0.11) [average number of cigarettes per day multiplied by number of years smoked divided by (reference age minus 13 years)] but none with age at start of regular smoking (data not shown).