TABLE 5

Caffeinated coffee consumption in relation to plasma SHBG levels and type 2 diabetes stratified by SHBG SNPs

SHBG genotype
rs6259rs6257
GG (wild type)AG or AA (variant)CT or CC (variant)TT (wild type)
Plasma SHBG levels (nmol/l)*nnnn
    Caffeinated coffee intake
        Low (<2 cups per day)27723.2 (16.6–32.5)7023.3 (16.4–32.9)6920.3 (14.2–29.0)28523.2 (16.6–32.4)
        High (≥2 cups per day)24624.4 (17.4–34.3)7627.8 (19.4–39.7)7221.6 (15.2–30.8)24425.2 (17.9–35.4)
P for interaction0.180.84
ORs(Case subjects/control subjects)(Case subjects/control subjects)(Case subjects/control subjects)(Case subjects/control subjects)
    Caffeinated coffee intake
        Low (<2 cups/day)152/1251.00 (reference)40/300.90 (0.40–2.00)42/271.00 (reference)149/1360.41 (0.19–0.88)
        High (≥2 cups/day)122/1240.70 (0.42–1.16)26/500.54 (0.26–1.11)34/380.40 (0.16–1.02)109/1350.38 (0.18–0.83)
P for interaction0.790.13
  • Data are OR (95% CI) and n.

  • *The multivariate-adjusted geometric mean SHBG levels with 95% CIs for combinations of SHBG genotypes and caffeinated coffee intake levels (≥2 vs. <2 cups/day) adjusted for matching factors, smoking status, physical activity, family history of diabetes, alcohol use, total calories, and BMI.

  • †Wald tests were used to test for statistical interaction by entering product terms into the regression models.

  • ‡The multivariate-adjusted ORs and 95% CIs of type 2 diabetes risk for combinations of SHBG genotypes and caffeinated coffee intake levels (≥2 vs. <2 cups/day) adjusted for matching factors, smoking status, physical activity, family history of diabetes, alcohol use, total calories, and BMI.