In a cohort of women aged 40-64 at entry, 12 h urine samples were obta
ined at the beginning of a follow-up period of up to 15 years in which
incident cases of lung cancer were registered as well as deaths from
lung cancer. In this cohort a nested case-control study (n = 397) was
carried out by measuring urinary cotinine. The method for quantitation
of cotinine was sensitive enough to study lung cancer risk not only i
n active smokers but also in passive smokers. The results seem to indi
cate that cotinine estimations in single 12 h samples of urine art eno
ugh to predict lung cancer risk Relative risk rose with increasing lev
els of nicotine intake already in the range associated with passive sm
oking. The smoking-related risk of adenocarcinoma was much less than t
hat of other lung carcinomas.