Table 2

NNAL, NNAL-Gluc, and total cotinine in the urine of elementary school-aged children

GroupNo. of familiesNo. of childrenpmol/mlTotal cotinine (ng/ml)
NNALNNAL-GlucNNAL + NNAL-Gluc
All66b74
 Meana (±SD)0.018c (±0.030)0.040d (±0.050)0.056e (±0.076)12.0 (±17.8)
 Geometric mean0.0050.0120.0152.5
 95% CI(0.003 to 0.009)(0.006 to 0.022)(0.008 to 0.028)(1.2 to 5.0)
Exposure reported33b38
 Meana (±SD)0.032f (±0.039)0.064g (±0.056)0.095h (±0.088)24.5i (±22.4)
 Geometric mean0.0110.0280.0412.6
 95% CI(0.006 to 0.021)(0.015 to 0.05)(0.022 to 0.074)(7.4 to 21.3)
No exposure reported32b35
 Meana (±SD)0.010 (±0.020)0.026 (±0.040)0.035 (±0.058)5.0 (±8.7)
 Geometric mean0.0030.0070.0081.0
 95% CI(0.001 to 0.007)(0.003 to 0.019)(0.003 to 0.023)(0.4 to 2.9)
Total cotinine <5 ng/ml1920
 Meana (±SD)0.005 (±0.010)0.012 (±0.020)0.016 (±0.030)1.2 (±1.6)
 Geometric mean0.0020.0040.0040.45
 95% CI(0.001 to 0.003)(0.002 to 0.01)(0.002 to 0.012)(0.2 to 1.0)
  • a Mean values are calculated from among family means, which in turn, are calculated from the student means within each family. The means are weighted to account for nonresponse and sample selection. For samples with levels below the detection limit, half of the minimum detectable level (0.0015 pmol/ml for NNAL and NNAL-Gluc and 0.2 ng/ml for cotinine) was added to calculate mean values.

  • b Of the 66 families that were tested for NNAL and NNAL-Gluc, only 1 family with 1 child did not have questionnaire data on exposure.

  • c Includes 28 not detected (ND), see footnote a.

  • d Includes 15 ND, see footnote a.

  • e Includes 12 ND, see footnote a.

  • f Significantly higher than “No exposure reported,” P = 0.002.

  • g Not significantly higher than “No exposure reported,” P = 0.053.

  • h Significantly higher than “No exposure reported,” P = 0.031.

  • i Significantly higher than “No exposure reported,” P < 0.001.