Nicotine measurement in hair is a practical and valid method for estimating average ETS exposure in children. An underreporting of ETS exposure was indicated.

Cord serum cotinine and thiocyanate concentrations are related to daily smoking rate during pregnancy, but these concentrations vary considerably among occasional smokers. Detailed information on smoking habits is the key issue in understanding the adverse fetal effects of occasional smoking during pregnancy.

To develop a procedure for maximizing the discrimination of smoking status, the authors analysed parallel samples of thiocyanate and cotinine in serum, and carbon monoxide (CO) in expired air in a cohort of 145 male subjects aged 45-65 years. The sensitivity and specificity were 93% and 82%, 97% and 83%, and 98% and 100% for thiocyanate, cotinine, and CO respectively. The results were not significantly improved when combining two or three methods as compared with CO separately. Also, cotinine in urine was analysed in a subgroup of 21 subjects. The correlation coefficient between cotinine in serum and urine was 0.92. In a subgroup of 44 subjects with extensive information on smoking habits, CO was the only indicator significantly related to the quantity of tobacco smoked. We conclude that CO seems sufficient for validating smoking status, but as atypical smokers who are vulnerable to misclassification may be overrepresented in smoking cessation programmes, combining two methods could still be useful. Validating the amount of tobacco smoked is of limited use with the current methods.

The aim of this study was to determine the impact of the administration route and cigarette smoking on plasma oestrogen levels during oral and parenteral oestrogen replacement therapy (ERT). Fourteen healthy postmenopausal women (six smokers and eight non-smokers) were recruited for a prospective, randomised, crossover study at a private outpatient medical centre in Oslo, Norway. All patients were randomised to receive cyclic therapy with oestradiol and norethisterone orally or by the transdermal route each for a 6-month period. Plasma levels of oestrone (Oe 1 ), oestradiol (Oe 2 ) and oestrone sulphate (Oe 1 S) were determined using highly sensitive RIA methods before and during hormone replacement therapy given by the oral and transdermal route. Comparing smokers and nonsmokers, plasma levels of Oe 1 , Oe 2 and Oe 1 S were all found to be 40-70% lower in smokers compared with non-smokers when ERT was given orally (Oe 1 S, P<0·05; Oe 1 and Oe 2 , P<0·01 for both). Oe 2 given orally caused a higher Oe 1 S/Oe 2 ratio but also a higher Oe 1 /Oe 2 ratio compared with parenteral therapy in smokers (40·2 versus 7 . 0, P<0·01; and 3·2 versus 0·8, P<0·05 respectively). No significant differences in these parameters in the different test-situations were seen in non-smokers. Except for a lower level of Oe 1 S in smokers (non-significant), no difference in plasma oestrogen levels between smokers and non-smokers was observed during parenteral therapy. In conclusion, cigarette smoking has been shown to have major impact on plasma oestrogen levels during oral but not during parenteral Oe 2 replacement.

No abstract