Kehl et al. BMC Public Health 2010, 10:424 http://www.biomedcentral.com/1471-2458/10/424 Table 2 Infants’ cotinine creatinine ratios (microgram/mmol) in urine during the period of 7 days Subject Sex Age Cotinine creatinine ratio (microgram/mmol) in infants’ urine no. (month) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 F F F F F M F M F M F M F M M F M M M F F F M F M M M M 2 3 4 6 6 6 7 8 8 8 11 11 12 13 18 20 20 23 26 26 27 29 30 32 33 35 38 43 Mean (SD) mon tue wed thu 165,93 664,62 570,83 937,50 20,41 20,83 22,34 38,46 * * * * 11,64 20,37 22,05 14,04 5,71 6,17 16,95 13,51 8,95 6,91 8,70 5,45 42,15 87,80 42,86 * 32,70 44,35 36,59 23,28 39,76 41,57 32,63 29,89 16,67 10,05 13,41 17,81 33,33 24,20 80,41 * 8,10 13,21 22,18 25,40 18,52 32,31 32,66 85,29 1,31 3,48 5,62 2,62 2,94 5,00 3,50 2,82 65,86 74,55 18,87 40,23 * * 3,68 * 12,94 11,98 12,89 20,00 4,95 2,53 3,30 1,92 23,61 20,38 27,21 * 8,17 3,70 15,15 6,02 5,88 2,01 2,89 2,77 6,67 6,27 4,60 4,81 27,04 43,35 26,49 - 14,85 8,96 7,54 - * 20,88 15,38 18,12 17,23 18,99 19,50 15,06 21,64 28,25 26,12 22,99 24.68 47.03 40.53 63.24 (33.01) (127.79) (107.23) (201.21) fri 290,00 22,73 * 14,77 10,99 - * 26,44 112,17 18,98 26,53 125,00 40,22 2,13 22,73 41,11 * 16,60 24,39 * 16,65 10,10 10,96 31,72 24,79 37,14 13,12 18,05 41.62 (61.71) sat sun 470,67 489,23 * 17,86 * * 12,30 18,57 13,33 8,26 - - 80,88 175,74 29,68 25,66 77,33 157,14 * * * 31,06 20,33 6,08 8,22 200,00 1,98 3,52 2,26 3,83 87,80 96,30 3,08 *. 42,36 17,41 3,38 3,45 * * 5,84 7,90 2,24 4,39 13,05 11,67 31,15 38,02 13,76 * 46,23 40,00 15,64 14,18 34,06 36,23 46.16 63.93 (98.39) (111.65) mean sd 512,68 251,36 23,77 7,40 - - 16,25 4,08 10,71 4,19 7,50 1,64 85,89 54,47 31,24 7,33 70,07 48,57 15,38 3,63 39,11 23,37 31,47 41,87 59,60 66,51 2,95 1,42 6,15 7,36 60,67 28,20 3,38 0,43 19,17 10,63 6,27 8,04 23,73 3,41 9,06 4,92 4,32 2,89 8,29 3,50 32,96 6,56 13,98 6,79 29,63 13,05 16,25 2,41 26,76 6,61 43.23 (96.27) Indoor - outdoor smoking indoor outdoor outdoor outdoor outdoor outdoor outdoor indoor indoor indoor indoor indoor indoor outdoor outdoor indoor outdoor indoor outdoor indoor outdoor outdoor outdoor indoor indoor indoor indoor indoor Page 5 of 8 No. of smokers in home 2 2 1 2 1 1 1 2 2 2 2 1 2 1 1 1 1 1 2 1 2 2 2 1 1 2 2 2 Notes: - = no material; * = too little material to analyse urine. Table 3 Smoking at home and infant cotinine-to-creatinine ratio Cotinine-to-creatinine ratio (μg/mmol) with log e transformation B SE z p > |z| 95% CI Household smoking Smoking outside the home Smoking inside the home Number of smokers living in home One smoker Two smokers Cpd smoked in the presence of the infant Time infants spend in rooms in which smoking occurs (minutes) Ref. 1.23 Ref. .33 .02 .00 0.41 0.44 0.05 0.00 3.00 0.75 0.43 0.96 < .01 .46 .67 .34 .43 -.54 -.08 -.00 2.04 1.20 .13 .01 Generalized estimation equation models predict the infant’s cotinine-to-creatinine ratio (CCR), taking into account cluster correlation within subjects across study days. Models are based on an exchangeable correlation structure for repeated observations within subjects. Predictor variables were adjusted for study day