Table 5.

Joint effect of the MTHFR genotypes/diplotypes and arsenic exposure on risk of skin lesions

MTHFR genotype/diplotypeJoint effect of MTHFR genotype/diplotype and time-weighted well arsenic concentration
Joint effect of MTHFR genotype/diplotype and urinary %MMA
TWA levelsMeans of TWAn (cases/controls)Adjusted ORs for skin lesions*P for interaction%MMAMeans of %MMAn (cases/controls)Adjusted ORs for skin lesionsP for interaction
MTHFR 677 (rs1801133)
    CC<7325.34155/3961.000.35<139.38150/4151.000.61
    CT<7329.5250/1081.13 (0.74-1.74)<139.7354/1071.32 (0.85-2.05)
    TT<7322.064/81.08 (0.28-4.19)<1310.132/60.44 (0.07-2.89)
    CC≥73204.92252/3182.15 (1.64-2.82)≥1317.24266/3241.36 (1.01-1.82)
    CT≥73204.5971/682.59 (1.69-3.96)≥1317.6070/781.38 (0.89-2.13)
    TT≥73195.458/35.73 (1.10-29.77)≥1317.7610/53.99 (1.05-15.13)
MTHFR 1298 (rs1801131)
    CC<7328.5420/701.000.38<139.2224/741.000.28
    AC<7325.5397/2350.99 (0.64-1.49)<139.5098/2470.97 (0.53-1.77)
    AA<7328.2588/1881.35 (0.87-2.08)<139.5387/1911.18 (0.64-2.18)
    CC≥73196.7942/592.14 (1.22-3.74)≥1318.1839/611.00 (0.49-2.05)
    AC≥73196.90148/1872.23 (1.49-3.35)≥1317.08152/1891.28 (0.71-2.33)
    AA≥73215.20140/1362.80 (1.84-4.26)≥1317.31147/1451.60 (0.87-2.94)
MTHFR diplotypes
    Other/other<7325.79149/3711.000.39<139.37147/3921.000.64
    TA/other<7329.9749/1021.21 (0.78-1.89)<139.7453/1041.29 (0.83-1.99)
    TA/TA<7322.064/81.07 (0.28-4.15)<1310.122/60.41 (0.07-2.37)
    Other/other≥73203.63241/3042.11 (1.57-2.82)≥1317.29252/3071.36 (1.02-1.81)
    TA/other≥73202.7468/682.47 (1.59-3.83)≥1317.5067/741.49 (0.97-2.29)
    TA/TA≥73195.458/36.31 (1.24-32.26)≥1317.7710/53.91 (1.06-14.41)
  • * ORs were adjusted for age and gender, smoking status, BMI, and water consumption per day. Cut points for TWA levels and % MMA were determined based on median values in the controls.

  • ORs were adjusted for age and gender, smoking status, BMI, water consumption per day, and well arsenic concentration.