Table 4.

The analyses were adjusted for the following variables

Ref.	Variables of adjustment
Abnet et al[28], 2005	Age and education
Abnet et al[27], 2001	Age, sex, tobacco use, and alcohol use
Hiraki et al[19], 2008	Age, sex, smoking and drinking status (never, former, current), vegetable and fruit intake, BMI, and regular exercise
Hujoel et al[20], 2003	Age and gender
Kim et al[21], 2022	Age
Michaud et al[29], 2008	Age (continuous), ethnic origin (white, Asian, black), physical activity (quintiles), history of diabetes (yes or no), alcohol (quartiles), BMI (< 22, 22-24.9, 25-29.9, 30 +), geographical location (south, west, northeast, mid-west), height (quintiles), calcium intake (quintiles), total calorific intake (quintiles), red-meat intake (quintiles), fruit and vegetable intake (quintiles), vitamin D score (deciles), smoking history (never, past quit ≤ 10 yr, past quit > 10 yr, current 1-14 cigarettes per day, 15-24 cigarettes per day, 25 + cigarettes per day), and pack-years (continuous)
Ndegwa et al[30], 2018	Age as time-scale, age at entry, sex, area of residence (rural, small-town or urban), tobacco use status (non-tobacco use, smoking only, snus only or mixed usage), and alcohol consumption (less than once a week versus once a week or more)
Shakeri et al[31], 2013	Age, ethnicity, education, fruit and vegetable use, socioeconomic status, ever opium or tobacco use, and denture use
Watabe et al[32], 1998	NA
Yano et al[33], 2021	Age, sex, socioeconomic score, ethnicity, residence, education, cigarette use, and opium use
Zhang et al[8], 2022	Age (continuous), sex, education (illiteracy, primary school, junior school, high school and above), marital status (single, married, divorced or widowed), job type (farmer, worker, others), wealth score (five levels), BMI 10 years ago (< 18.5 kg/m2, 1.85 to 24.0 kg/m2, 24.0 to 28.0 kg/m2, ≥ 28.0 kg/m2), tobacco smoking (never, ≤ 30 pack-years, > 30 pack-years), alcohol drinking (never, ≤ 80 g/d, > 80 g/d), H. pylori seropositivity (yes/no), and family history of GC (yes/no)
Zhang et al[34], 2022	Age (continuous), sex (male, female), BMI (continuous), study sites (10 sites), education level (no formal school, primary or middle school, high school and above), marital status (married, other), household income per year (< 10000, < 10000-19999, < 20000-34999, or < 35000), alcohol consumption (non-drinker, occasional drinker, former drinker, or regular drinker), smoking status (never smoker, occasional smoker, former smoker, or regular smoker), physical activity in MET hours a day (continuous), aspirin prescription for CVD (no, yes, or missing), menopausal status (pre-menopausal or post-menopausal, women only), personal history of diabetes (no, yes), and family history of cancer (no, yes)

BMI: Body mass index; MET: Metabolic equivalent tasks; CVD: Cardiovascular disease; NA: Not applicable; H. pylori: Helicobacter pylori; GC: Gastric cancer.