Table 2 Reported results and statistical adjustments in the prospective studies included in the meta-analysis

Jacobsen, 1986 [19]

≥7 vs. ≤ 2 cups/d

0.99 (0.53–1.86)

0.98 (0.47–2.03)(M)

Age, sex, residence, and smoking (for M only)

Never, former, current (1–9, 10–19, ≥20 cig/d) (for M only)

Mills, 1991 [26]

≥2 cups/d vs. never

1.99 (0.91–4.34)

2.03 (0.70–5.87)(NS)

1.14 (0.46–2.80)(FS/CS)

Age, sex, and smoking

Never, former, current

Chyou, 1993 [27]

≥5 vs. ≤ 1 times/wk

2.07 (0.84–5.12)

Age and smoking

Pack-years (0, > 0–30, > 30)

Stensvold, 1994 [15]

≥7 vs. ≤ 2 cups/d

1.50 (0.45–5.02)(M)

2.40 (0.28–20.5)(W)

Age, residence, and smoking

Cig/d (continuous)

Michaud, 1999 [28]

≥4 cups/d vs. < 1 cup/mo

0.79 (0.48–1.30)

Age, region, energy intake, fruit and vegetable intake, and smoking

Smoking status (smoker, nonsmoker) and pack-years (6 categories)

Nagano, 2000 [29]

≥5 vs. 0 times/wk

0.90 (0.52–1.56)

Age, sex, radiation dose, education, BMI, calendar time, and smoking

Never, former, current (≤20, > 20 cig/d)

Zeegers, 2001 [16]

≥7 (M)/≥5(W) vs. < 2 cups/d

1.36 (0.82–2.04)(M)

0.32 (0.15–0.68)(W)

Age, tea consumption, and smoking

Cig/d (continuous), years of smoking (continuous)

Tripathi, 2002 [30]

≥4 cups/d vs. < 1 cup/mo

1.59 (0.95–2.68)

Age

None

Kurahashi, 2019 [17]

≥3(M)/≥1(W) cup/d vs. almost never

1.37 (0.75–2.51)(M)

0.55 (0.23–1.33)(W)

2.48 (0.88–7.05)(NS)(M)

2.09 (0.96–4.54)(FS)(M)

2.24 (1.21–4.16)(NS/FS)(M)

1.13 (0.65–1.97)(CS)(M)

Age, area, alcohol, green tea consumption, and smoking

Never, former, current (< 25, ≥25 pack-years)

Ros, 2011 [21]

≥875(M)/500(W) ml/d vs. < 429 (M)/250(W) ml/d

1.11 (0.85–1.43)

Age, sex, center, energy intake, and smoking.

Smoking status (never, former and current), duration (continuous), and lifetime intensity (continuous)

Hashibe, 2015 [31]

≥2 vs. < 1 cup/d

1.08 (0.85–1.39)

Age, sex, race, education, and smoking

Smoking status (never, former, current), frequency (1–10, 11–20, 21–30, > 30 cig/d), duration (1–10, 11–20, > 20 yr), years since quitting (> 0–2, 3–5, 6–10, 11–20, > 20 yr).

Loftfield, 2017 [6]

≥4 cup/d vs. none

1.18 (1.05–1.33)

1.25 (1.09–1.43)(M)

0.97 (0.74–1.25)(W)

0.87 (0.65–1.17)(NS)

1.23 (1.04–1.33)(FS)

1.32 (0.95–1.81)(CS)

Age, sex, race/ethnicity, BMI, education, reported health status, fruit intake, vegetable intake, supplement use, physical activity, diabetes, family history of cancer, and smoking

Pipes or cigars (ever, never), smoking frequency (1–10, 11–20, 21–30, 31–40, 41–60, ≥60 cig/d), years since quitting (≥1–4, 5–9, ≥10 yr).

Sugiyama, 2017 [7]

≥3 cup/d vs. none

0.56 (0.32–0.99)

0.57 (0.31–1.07)(M)

0.44 (0.10–1.97)(W)

0.62 (0.14–2.72)(NS)

0.61 (0.32–1.17)(FS/CS)

Age, sex, BMI, hypertension, diabetes, MI, stroke, job status, education, alcohol, green tea consumption, walking, and smoking

Never, former, current (< 20, ≥20 cig/d)

Gapstur, 2017 [5]

≥6 cup/d vs. never

0.89 (0.73–1.09)(NS/FS)

0.80 (0.57–1.12)(NS)

0.97 (0.74–1.27)(FS)

Age, sex, race, marital status, education, alcohol consumption, BMI, physical activity, family history of cancer, red and processed meat intake, vegetable intake, tea consumption, and smoking.

Years since quitting (< 10, 10- < 20, ≥20 yr) and cig/d (< 20, 20–29, ≥30).

Lukic, 2018 [8]

≥4 vs. < 1 cup/d

1.34 (0.94–1.90)

1.23 (0.78–1.95)(M)

1.46 (0.84–2.51)(W)

1.87 (1.01–3.45)(NS)

1.18 (0.77–1.81)(FS/CS)

Age, sex, and smoking

Never, former, current

Hashemian, 2019 [9]

≥4 vs. < 1 cup/d

1.10 (0.81–1.49)(CS)

Age, education, alcohol, diabetes, physical activity, fruit intake, vegetable intake, tea consumption, and smoking

Smoking years (continuous), cig/d (continuous)