Table 4.
Multiple regression analysis for biomarkers (adjusted for creatinine) The model for each biomarker includes all the covariates from the univariate analysis that were significant with p-value<0.1.
| Dependent variable=TNE nmol/mg creatinine (N=343) | R-squared=0.32 | |
| Covariates | Coefficent (SE) | P-value |
| Intercept | 1.9 (20.0) | 0.925 |
| Annual income > 15K | −5.1 (7.1) | 0.470 |
| Number of years using snuff daily | 1.3 (0.3) | <0.001 |
| Age when 1st used snuff | 0.04 (0.42) | 0.937 |
| Dependence score | −0.5 (1.0) | 0.608 |
| Tins per week (tobacco history form) | 5.0 (1.7) | 0.004 |
| Mean dips per day | −0.2 (2.2) | 0.945 |
| Mean duration per dip (min) | −0.01 (0.20) | 0.958 |
| Mean daily dipduration (hr) | 7.6 (2.4) | 0.002 |
| Constituent yield: Free nicotine mg/g wet wt | −1.9 (2.2) | 0.402 |
| Dependent variable=total NNAL pmol/mg creatinine* (N=342) | R-squared=0.50 | |
| Covariates | exp(Coeff) (95% CI) | P-value |
| Annual income > 15K | 0.97 (0.81, 1.16) | 0.724 |
| Number of years using snuff daily | 1.02 (1.01, 1.03) | <0.001 |
| Age when 1st used snuff | 1.00 (0.99, 1.01) | 0.520 |
| Dependence score | 1.00 (0.98, 1.03) | 0.939 |
| Tins per week | 1.13 (1.08, 1.18) | <0.001 |
| Mean dips per day | 1.05 (0.99, 1.11) | 0.089 |
| Mean duration per dip (min) | 1.01 (1.00, 1.01) | 0.045 |
| Mean daily dip duration (hr) | 1.07 (1.01, 1.14) | 0.027 |
| Constituent yield: NNK µg/g wet wt | 1.38 (1.16, 1.64) | <0.001 |
| Constituent yield: NNK/free nicotine | 0.84 (0.50, 1.39) | 0.497 |
| Dependent variable=total NNN pmol/mg creatinine* (N=326) | R-squared=0.43 | |
| Covariates | exp(Coeff) (95% CI) | P-value |
| Annual income > 15K | 0.85 (0.69, 1.06) | 0.156 |
| Number of years using snuff daily | 1.02 (1.01, 1.03) | <0.001 |
| Age when 1st used snuff | 1.01 (1.00, 1.02) | 0.180 |
| Dependence score | 1.01 (0.98, 1.04) | 0.473 |
| Smoked >100 cigarettes in lifetime | 1.21 (0.99, 1.49) | 0.067 |
| Tins per week | 1.12 (1.06, 1.18) | <0.001 |
| Mean dips per day | 1.04 (0.97, 1.11) | 0.301 |
| Mean duration per dip (min) | 1.01 (1.00, 1.01) | 0.067 |
| Mean daily dip duration (hrs) | 1.07 (1.04, 1.15) | 0.058 |
| Constituent yield: NNN µg/g wet wt | 1.12 (1.05, 1.20) | 0.001 |
| Constituent yield: NNN/free nicotine | 0.94 (0.76, 1.18) | 0.614 |
*
Analyzed in the logarithmic scale
Note: For total NNN/creat, one subject with NNN >60 was excluded from the analysis