Table 1.
Summary characteristics of studies included in the meta-analysis
| Study | Country | Follow-up period | Study subjects | No. of cases | Coffee consumption | Relative risk (95% CI) | Adjustments |
| Snowdon et al[12] | United States | 1960-1980 | 23 912 | 71 | < 1 cup/d | 1.00 (reference) | Age, sex |
| Aged ≥ 30 yr | 1 cup/d | 1.7 (0.9-3.3) | |||||
| 1984 | ≥ 2 cups/d | 0.8 (0.4-1.6) | |||||
| Jacobsen et al[13] | Norway | 1967-1978 | 16 555 | 63 | ≤ 2 cups/d | 1.00 (reference) | Sex, age and residence (men for cigarette smoking) |
| 13 664 male | 3-4 cups/d | 1.22 (0.66-2.35) | |||||
| 1986 | 2891 female | 5-6 cups/d | 0.53 (0.21-1.26) | ||||
| ≥ 7 cups/d | 0.62 (0.18-1.75) | ||||||
| Nomura et al[14] | Japan | 1965-1983 | 7355 male | 21 | 0 cup/d | 1.00 (reference) | Age, years of smoking, number of cigarettes smoked per day, smoking status at exam, and past smoking status |
| 1-2 cups/d | 0.83 (0.16-5.34) | ||||||
| 1986 | 3-4 cups/d | 1.39 (0.32-8.31) | |||||
| ≥ 5 cups/d | 1.27 (0.27-7.84) | ||||||
| Hiatt et al[15] | United States | 1978-1984 | 122 894 | 49 | < 1 cup/d | 0.4 (0.1-4.3) | Age, sex, ethnic origin, blood glucose levels, consumption of alcohol, tea |
| 1988 | 1-3 cups/d | 1.2 (0.3-4.4) | |||||
| > 4 cups/d | 0.8 (0.2-4.6) | ||||||
| Zheng et al[16] | United States | 1966-1986 | 17 633 male | 57 | < 3 cups/d | 1.00 (reference) | Age, smoking index, alcohol index |
| Aged ≥ 35 yr | 3-4 cups/d | 0.6 (0.3-1.2) | |||||
| 1993 | 5-6 cups/d | 0.7 (0.4-1.6) | |||||
| ≥ 7 cups/d | 0.9 (0.3-2.4) | ||||||
| Shibata et al[17] | United States | 1981-1990 | 13 979 | 63 | < 1 cup/d | 1.00 (reference) | Sex, age and cigarette smoking |
| 1 cup/d | 1.82 (0.75-4.43) | ||||||
| 1994 | 2-3 cups/d | 1.67 (0.74-3.77) | |||||
| ≥ 4 cups/d | 0.88 (0.28-2.80) | ||||||
| Stensvold et al[18] | Norway | 1977-1990 | 42 973 | 41 | ≤ 2 cups/d | 1.00 (reference) | Age, cigarette smoking, county of residence |
| 21 735 male | 26 M | 3-4 cups/d | 2.76 (0.63-25.21) | ||||
| 1994 | 21 238 female | 15 F | 5-6 cups/d | 3.09 (0.72-27.87) | |||
| Aged 35-54 yr | ≥ 7 cups/d | 2.71 (0.59-25.15) | |||||
| Zheng et al[19] | United States | 1986-1993 | 35 369 female | 66 | Never/monthly | 1.00 (reference) | Age, education, smoking status, pack-years of smoking, physical activity, all fruit and vegetable intake, total energy intake, waist/hip ratio, family history of cancer, prior history of blood transfusion |
| Aged 55-69 yr | Weekly-3 cups/d | 1.82 (0.87-3.82) | |||||
| 1996 | ≥ 4 cups/d | 2.15 (1.01-4.07) | |||||
| Michaud et al[20] | United | 1986-1998 | 136 593 | 288 | None | 1.00 (reference) | Age in 5-yr categories, pack-years of smoking, bidy mass index, history of diabetes mellitus, history of cholecystectomy, energy intake, and period |
| States | 1980-1996 | 47 794 male | 130 M | < 1 cup/d | 0.94 (0.65-1.36) | ||
| 2001 | Aged 40-75 yr | 158 F | 1 cup/d | 0.60 (0.38-0.94) | |||
| 88 799 female | 2-3 cups/d | 0.88 (0.65-1.21) | |||||
| Aged 30-55 yr | > 3 cups/d | 0.62 (0.27-1.43) | |||||
| Isaksson et al[21] | Sweden | 1961-1997 | 21 884 | 131 | 0-2 cups/d | 1.00 (reference) | Sex, age, cigarette smoking |
| 9680 male | 3-6 cups/d | 0.91 (0.60-1.38) | |||||
| 2002 | 12 204 female | ≥ 7 cups/d | 0.39 (0.17-0.89) | ||||
| Aged 36-75 yr | |||||||
| Lin et al[22] | Japan | 1988-1997 | 99 527 | 225 | Nondrinkers | Age, cigarette smoking in pack-years | |
| 2002 | 44 646 male | 1-2 cups/mo | |||||
| 54 881 female | 1-4 cups/wk | ||||||
| Aged 40-79 yr | 1 cup/d | ||||||
| 2-3 cups/d | |||||||
| ≥ 4 cups/d | |||||||
| Stolzenberg-Solomon et al[23] | Finland | 1985-1997 | 27 111 male | 163 | ≤ 321.4 g/d | 1.00 (reference) | Age, years of smoking |
| Aged 50-69 yr | > 321.4-≤ 450.0 g/d | 1.48 (0.89-2.46) | |||||
| > 450.0-≤ 624.9 g/d | 1.12 (0.61-2.03) | ||||||
| 2002 | > 624.9-≤ 878.6 g/d | 1.72 (1.01-2.86) | |||||
| > 878.6 g/d | 0.95 (0.54-1.68) | ||||||
| Khan et al[24] | Japan | 1984-2002 | 3158 | 25 | ≤ several times/mo | 1.00 (reference) | Age, sex, health education, health examination, health status, moking |
| 2004 | 1524 male | 12 M | ≥ several times/wk | 0.38 (0.01-1.05) | |||
| 1634 female | 13 F | ||||||
| Aged ≥ 40 yr | |||||||
| Luo et al[25] | Japan | 1990-2003 | 102 137 | 233 | Rarely | 1.00 (reference) | Body mass index, frequency of sports, smoking status, alcohol intake, history of diabetes, history of cholelithiasis, study area, age and tea consumption |
| 2007 | 48 783 male | 135 M | 1-2 cups/wk | 1.0 (0.7-1.4) | |||
| 53 354 female | 98 F | 3-4 cups/wk | 1.1 (0.7-1.7) | ||||
| Aged 40-69 yr | 1-2 cups/d | 0.9 (0.6-1.3) | |||||
| ≥ 3 cups/d | 0.8 (0.4-1.3) |