. Author manuscript; available in PMC: 2013 Apr 19.

Published in final edited form as: Pediatr Res. 2012 Mar 22;72(1):101–107. doi: 10.1038/pr.2012.36

Table 3.

Summary Statistics of Cut-off Between Active Smokers and Non-smokers /Passive Smokers Among 2,997 Women in The Norwegian Mother and Child Cohort Study, 2002–2003^a

		Percentile
	Mean	2.5th	25th	50th	75th	97.5th
Cut-off (cotinine units: nmol/l)^b	29.8	20.0	26.5	29.6	32.2	56.0
Sensitivity (%)^c	81.9	77.3	80.4	82.0	83.5	86.4
Specificity (%)^c	99.4	99.1	99.3	99.4	99.6	99.7

Estimates found by 10,000 re-samplings of the observed data (non-parametric bootstrap method).

Antilog of logarithmic values.

Sensitivity and specificity for self-reported daily smoking: information on smoking habits during pregnancy was missing for 22 women and excluded for 27 women using other kinds of nicotine products.