Table S2. Characteristics of the studies included in the meta-analysis^*.

Study	No. of participants	Age (years)	Endpoints (no. of cases)	Follow-up period	Exposure and assessment method (exposure)	Outcome assessment	Daily consumption (exposure)	Year of recruitment	Covariates in fully adjusted model	Quality score
Abbreviation: CHNS=China Health and Nutrition Survey (China); CKB=China Kadoorie Biobank (China); SW(M)HS=Shanghai Women’s (Men’s) Health Study (China); KoGES=Korean Genome Epidemiology Study (Republic of Korea); SCHS=Singapore Chinese Health Study (Singapore); JPHC=Japan Public Health Center-based Prospective Study (Japan). DM=diabetes mellitus; T2DM=type 2 diabetes mellitus; FFQ=food frequency questionnaire; g=grams; Q=quartile; SD=standard deviation; NA=not applicable.
Liu et al. (2021) CHNS, China (9)	16,117	Mean: 43.0 (SD: 15.2)	DM (1,088)	Median: 9.0 years; 158,018 person-years	Three consecutive 24-hour dietary recalls (unprocessed red meat, processed meat)	Self-reported	Median: 58.9 g (unprocessed red meat); median: 0 g (processed meat)	1997	Age, sex, BMI, waist circumference, smoking and drinking status, systolic blood pressure, diastolic blood pressure, education, region, occupation, physical activity, urban residence, as well as total energy, and 12 food groups were mutually adjusted.	6
Du et al. (2020) CKB, China (8)	461,036	Mean: 51.2 (SD: 10.5); 35–74 years	DM (14,931)	Mean: 9 years; 4.5 million person-years	Laptop-based FFQ (total red and processed meat)	Linkages with chronic disease registries and national health insurance claim databases	Mean: 55.1 g (total red and processed meat)	2004–2008	Age, sex, region, education, income, smoking, alcohol consumption, physical activity, family history of diabetes, and fresh fruit consumption, two main dietary exposure variables, and BMI.	9
Yu et al. (2018) SWHS & SMHS, China (10)	64,802 Women and 53,117 men	40–74 years	T2DM (6,111)	Mean: 11.5 years (13.6 years for women; 8.8 years for men).	Semiquantitative FFQ (unprocessed red meat, processed meat)	Self-reported diagnosis	NA	1996–2000 (women); 2002–2006 (men)	Total energy intake, education, income, smoking, alcohol drinking, leisure-time exercise, family history of diabetes, history of hypertension, history of dyslipidemia, and, in women, menopausal status, BMI, and all eight food groups were mutually adjusted.	6
Son et al. (2018) KoGES, Republic of Korea (11)	8,618	40–69 years	T2DM (668)	62,130 person-years	Semiquantitative FFQ (processed meat)	Self-reported interviews	Median: 0 g (processed meat)	2001–2002 and 2005–2006	Age, sex, educational level, monthly household income, and residential area, smoking, physical activity, BMI, alcohol intake, energy intake, consumption levels of dietary fat, crude fiber, sodium, fruit and vegetable, current use of antihypertensive and antihyperlipidemic medications.	7
Talaei et al. (2017) SCHS, Singapore (6)	45,411	Mean: 55.2 (SD: 7.6); 45–74 years	T2DM (5,207)	Mean: 10.9 years; 494,741 person-years	Semiquantitative FFQ (total red and processed meat, unprocessed red meat, processed meat)	Self-reported interviews	Median of Q1–Q4 (total red and processed meat): 12.3 g, 24.2 g, 33.4 g, 48.8 g; median of Q1–Q4 (unprocessed red meat): 10.5 g, 20.7 g, 29.0 g, 43.5 g; median of Q1–Q4 (processed meat): 0 g, 1.4 g, 2.57 g, 5.39 g	1993–1998	Age, sex, dialect, year of interview, and educational level, BMI, physical activity level, smoking status, alcohol use, baseline history of self-reported hypertension, adherence to the vegetable-, fruit-, and soy-rich dietary pattern, and total energy intake, heme iron intake	8
Kurotani et al. (2013) JPHC, Japan (7)	63,849	45–75 years	T2DM (1,178)	Max: 5 years	Self-administered FFQ (total red and processed meat, unprocessed red meat, processed meat)	Self-reported interviews	Men: median of Q1–Q4 (total red and processed meat): 17.9 g, 36.5 g, 56.4 g, 94.9 g; median of Q1–Q4 (unprocessed red meat): 15.1 g, 31.4 g, 49.0 g, 82.7 g; median of Q1–Q4 (processed meat): 0 g, 2.4 g, 5.6 g, 14.6 g; women: median of Q1–Q4 (total red and processed meat): 15.2 g, 32.0 g, 49.5 g, 82.9 g; median of Q1–Q4 (unprocessed red meat): 12.3 g, 26.9 g, 42.4 g, 72.2 g; median of Q1–Q4 (processed meat): 0 g, 2.4 g, 5.6 g, 13.5 g	1990 and 1993	Age, public health center area, BMI, smoking status, alcohol consumption, total physical activity, the history of hypertension, coffee consumption, the family history of diabetes, Mg intake, Ca intake, rice intake, fish intake, vegetable intake, soft drink consumption and energy intake	6
Villegas et al. (2006) SWHS, China (12)	70,609	Mean: 51.7 (SD: 8.97); 40–70 years	T2DM (1,972)	Mean: 4.6 years; 326,625 person-years	FFQ (unprocessed red meat, only for dose-response)	Self-reported type 2 diabetes identified through the baseline and follow-up surveys	Median: 42.6 g (unprocessed red meat)	1997–2000 (women)	Age, energy intake, BMI, WHR, smoking, alcohol consumption, physical activity, vegetable intake, income level, education level, occupation status, hypertension, and chronic disease	6