Skip to main content

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

From: Association between coffee consumption and risk of bladder cancer in a meta-analysis of 16 prospective studies

Author, years Consumption, highest vs. lowest RR (95% CI), highest vs. lowest Covariate adjustment Smoking adjustment
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)
  1. Abbreviations: BMI body mass index, cig cigarettes, CS current smoker, FS former smoker, M men, MI myocardial infarction, mo month, NS never smoker, W women, wk, week
  2. a 95% CIs were calculated using raw data
  3. b Data were rescaled by using the lowest consumption group as the reference