Table 1.
Baseline characteristic of studies included in the systematic review and meta-analysis
| Study | Country | Sex | Sample size | Age (years) | Never smoker | Former smoker | Current smoker | Follow-up (years) | Reported outcomes | Adjusted factors | NOS score |
|---|---|---|---|---|---|---|---|---|---|---|---|
| JACC 2005 [24] | Japan | Men | 43,482 | 57.4 | 9014 | 11,471 | 22,997 | 9.9 | GC mortality | Age, smoking, alcohol intake, educational level, preference for salty foods and green-tea intake. | 7 |
| Women | 43,482 | 57.4 | 9014 | 11,471 | 22,997 | ||||||
| Kato 1992 [25] | Japan | Men | NA | > 30.0 | NA | NA | NA | 6.0 | GC mortality | Age | 6 |
| Women | NA | > 30.0 | NA | NA | NA | ||||||
| Tverdal 1993 [26] | Norway | Men | 44,290 | 35.0–49.0 | 9334 | 10,467 | 18,400 | 13.3 | GC mortality | Age, cholesterol, SBP, PI during leisure, BMI, height and number of cigarettes. | 7 |
| Women | 24,535 | 35.0–49.0 | 12,369 | 3079 | 8954 | ||||||
| Engeland 1996 [27] | Norway | Men | 8905 | 23.0–57.0 | NA | NA | NA | 28.0 | GC | NA | 7 |
| Women | 10,169 | 18.0–57.0 | NA | NA | NA | ||||||
| Lindblad 2005 [28] | UK | Men | 6860 | 40.0–84.0 | 2956 | 678 | 1212 | NA | GC | Age, calendar year, BMI, alcohol consumption and reflux | 6 |
| Women | 3335 | 40.0–84.0 | 1744 | 168 | 395 | ||||||
| Jee 2004 [29] | Korea | Men | 830,139 | 45.0 | 166,858 | 190,932 | 473,179 | 8.0 | GC mortality | Age | 8 |
| Women | 382,767 | 48.6 | 352,528 | 9569 | 20,669 | ||||||
| Chao 2002 [30] | US | Men | 467,788 | 57.0 | 117,968 | 179,833 | 151,406 | 14.0 | GC mortality | Age, race, education, family history of stomach cancer, consumption of high-fiber grain foods, vegetables, citrus fruits or juices, and use of vitamin C, multivitamins, and aspirin | 8 |
| Women | 588,053 | 56.0 | 326,835 | 122,455 | 122,465 | ||||||
| Akiba 1990 [31] | Japan | Men | 122,261 | > 40.0 | NA | NA | NA | 16.0 | GC mortality | Prefecture of residence, occupation, attained age, and observation period | 6 |
| Women | 142,857 | > 40.0 | NA | NA | NA | ||||||
| Gonzalez 2003 [32] | Europe (10 countries) | Men | 148,182 | 51.6 | 49,678 | 36,791 | 36,643 | 5.0 | GC | Age, sex, vegetables, fruits, processed meat, alcohol, BMI and educational level | 7 |
| Women | 322,046 | 51.6 | 191,037 | 41,887 | 58,319 | ||||||
| Nomura 2012 [33] | US | Men | 82,683 | 60.1 | 25,466 | 42,251 | 14,966 | 7.3 | GC | Age at cohort entry as a continuous variable, ethnicity as a strata variable, education, processed meat intake, BMI, alcohol intake, aspirin use, and family history of gastric cancer | 8 |
| Women | 99,758 | 59.6 | 56,463 | 28,930 | 14,365 |
GC gastric cancer, SBP systolic blood pressure, PI physical activity, BMI body mass index