Table 4 Odds ratios (ORs) and 95 % confidence intervals (CIs) for high levels of serum gamma-glutamyltransferase (GGT) by Mt5178 C/A genotype and coffee consumption

Serum GGT levels <60 U/L

Serum GGT levels ≥60 U/L

Mt5178C

 <1 cup per day

69 (60.0)

46 (40.0)

1 (reference)

1 (reference)

 1–2 cups per day

52 (65.8)

27 (34.2)

0.779 (0.429–1.414)

0.575 (0.280–1.177)

 ≥3 cups per day

43 (75.4)

14 (24.6)

0.488 (0.240–0.993)*

0.313 (0.110–0.640)**

P for trend = 0.049

P for trend = 0.002

Mt5178A

 <1 cup per day

41 (66.1)

21 (33.9)

1 (reference)

1 (reference)

 1–2 cups per day

36 (52.9)

32 (47.1)

1.735 (0.854–3.528)

1.775 (0.775–4.066)

 ≥3 cups per day

27 (67.5)

13 (32.5)

0.940 (0.404–2.189)

0.838 (0.320–2.190)

P for trend = 0.911

P for trend = 0.711

Serum GGT levels ≤51 U/L

Serum GGT levels >51 U/L

Mt5178C

 <1 cup per day

62 (53.9)

53 (46.1)

1 (reference)

1 (reference)

 1–2 cups per day

48 (60.8)

31 (39.2)

0.756 (0.422–1.352)

0.569 (0.280–1.155)

 ≥3 cups per day

42 (73.7)

15 (26.3)

0.418 (0.209–0.837)*

0.231 (0.095–0.561)**

P for trend = 0.015

P for trend < 0.001

Mt5178A

 <1 cup per day

37 (59.7)

25 (40.3)

1 (reference)

1 (reference)

 1–2 cups per day

32 (47.1)

36 (52.9)

1.665 (0.830–3.339)

1.709 (0.746–3.911)

 ≥3 cups per day

23 (57.5)

17 (42.5)

1.094 (0.488–2.450)

1.025 (0.412–2.549)

P for trend = 0.673

P for trend = 0.988