Table 2.

Results from two conditional logistic regression spline models with the outcome skin lesions (n = 1708)

Main effects model
Interaction model
OR (95% CI)OR (95% CI)
Hb (threshold at 12 g/dL)0.79 (0.69-0.91)
    Males— (—)0.60 (0.49-0.73)
    Females— (—)1.16 (0.92-1.46)
BMI1.01 (0.97-1.05)1.01 (0.96-1.05)
Education
    No school (able to write)1.18 (0.80-1.73)1.24 (0.83-1.85)
    Primary0.81 (0.50-1.30)0.84 (0.52-1.38)
    Secondary0.48 (0.30-0.74)0.45 (0.28-0.72)
    College+0.90 (0.44-1.85)0.35 (0.17-0.73)
Smoked cigarettes0.80 (0.53-1.22)0.77 (0.49-1.19)
Smoked biri0.48 (0.31-0.74)0.45 (0.28-0.71)
Chewed betel nuts1.44 (1.00-2.09)1.50 (1.02-2.19)
Chewed tobacco0.49 (0.31-0.78)0.48 (0.30-0.77)
Logged toenail arsenic1.79 (1.52-2.10)1.82 (1.54-2.15)
Spline (logged water arsenic) linear1.14 (1.05-1.23)1.13 (1.04-1.23)
Nonlinear (P < 0.0001)Nonlinear (P < 0.0001)
  • NOTE: The first model presents main effects and the second an interaction between gender and Hb. The estimates for Hb are valid above a level of 12 g/dL.