Supplementary Table 1 . Information About Hospital, Ward, and Main Reason for Admission

Supplementary Table 1. Information about hospital, ward, and main reason for admission for controls Hospitals No. of Main reasons for admission (no. of controls) controls (n= 1663) Sher-i-Kashmir Institute of Medical Sciences (SKIMS) General Surgery ward 119 Appendicitis (20); hernias (18); liver/spleen trauma (17); biliary stones (16); fistulas (13); ascites (11); benign intestinal obstruction (10); others (14) Nephrology/Urology ward 79 Urinary stones (36); prostatitis (20); hydronephrosis (14); renal transplant (6); others (3) General Medicine, 252 Pancreatitis (39); fever work up (31); cholangitis (29); Gastroenterology, and chronic liver diseases, liver abscess (22); non- Cardiology wards cancerous pleural effusion (22); viral syndromes (20); diabetes and its complications (19); arrhythmia work up (17); urinary infection (12); commonly acquired pneumonia (8); others (33) Other wards (Indoor Clinical 18 Benign brain tumors (3); trauma/accidents (15) Laboratory, Accident and Emergency) Government Medical 30 Hydronephrosis (5); prostatitis (4); jaundice (4); College Hospital * typhoid fever (3); appendicitis (3); acute nephiritis (3); urinary stones (2); hernias (3); diarrhea (2); pancreatitis (1) District hospitals * Anantnag 236 Appendicitis (28); jaundice, hepatitis, pancreatitis (25); biliary stones (20); round worm infestations (20); hernias (19); urinary stones (17); trauma and soft tissue injuries (16); benign intestinal obstruction (14); asthma (10); others (67) Bandipora 74 Jaundice, hepatitis, pancreatitis (10); appendicitis (9); urinary tract infection (8); cataract (8); urinary stones (8); asthma (5); others (26) Budgam 59 Hernias and soft tissue injuries (12); round worm infestations (8); appendicitis (6); asthma (6); urinary tract infection (6); jaundice (5); others (15) Baramullah 234 Biliary stones (25); jaundice, hepatitis, pancreatitis (24); trauma and soft tissue injuries (23); ophthalmologic problems (22); commonly acquired pneumonia (19); urinary stones (18); urinary tract infection (18); appendicitis (15); hernias (15); others (55) Ganderbal 71 Jaundice (11); typhoid fever (10); urinary stones (9); appendicitis (9); biliary stones (6); hernias (4); prostatitis (4); others (18) Kulgam 75 Appendicitis (9); biliary stones (9); round worm

1 infestations (8); hernias (8); trauma and soft tissue injuries (8); urinary stones (7); others (26) Kupwara 95 Biliary stones (12); jaundice, hepatitis, pancreatitis (12); urinary stones (11); appendicitis (10); hernias (9); urinary tract infection (7); others (34) Pulwama 227 Biliary stones (22); round worm infestations (18); urinary tract infection (17); ophthalmologic problems (17); appendicitis (15); trauma and soft tissue injuries (15); prostatitis (14); jaundice, hepatitis, pancreatitis (11); urinary stones (10); hernias (9); benign intestinal obstruction (9); others (70) Shopian 94 Appendicitis (13); biliary stones (12); round worm infestations (10); jaundice, hepatitis, pancreatitis (10); hernias (9); urinary tract infection (8); others (32) * Government Medical College Hospital and district hospitals are general hospitals with few specialized wards.

2 Supplementary Table 2. Association between hookah and nass use, among never-users of the other product and cigarette, and risk of ESCC Tobacco use ESCC Matched Unadjusted Adjusted cases controls OR (95% CI) OR (95% CI) N (%) N (%) Hookah smoking Never 193 (43.1) 766 (61.0) Referent Referent Ever 255 (56.9) 492 (39.1) 2.20 (1.66-2.90) 1.85 (1.30-2.64) Cumulative use Never use 193 (43.1) 766 (61.0) Referent Referent 1 – 139 hookah-years 53 (11.8) 149 (11.9) 1.53 (1.02-2.30) 1.22 (0.74-2.04) 140 – 240 62 (13.8) 176 (14.0) 1.68 (1.14-2.50) 1.44 (0.85-2.43) ≥ 241 140 (31.3) 165 (13.1) 4.20 (2.81-6.28) 3.61 (2.18-5.97) P for trend <0.001 <0.001 Nass chewing Never 193 (70.7) 766 (91.9) Referent Referent Ever 80 (29.3) 68 (8.1) 8.18 (4.13-16.18) 5.45 (2.29-13.01) Cumulative use Never use 193 (71.2) 765 (91.9) Referent Referent 1 – 119 nass-years 9 (3.3) 12 (1.4) 7.57 (2.11-27.16) 11.59 (1.87-71.89) 120 – 199 14 (5.2) 27 (3.2) 3.58 (1.22-10.53) 2.05 (0.45-9.29) ≥ 200 55 (20.3) 29 (3.5) 12.00 (5.06- 6.63 (2.22-19.80) 28.49) P for trend <0.001 <0.001 Abbreviations: 95% CI, 95% confidence interval; ESCC, esophageal squamous cell carcinoma; OR, odds ratio. ORs (95% CIs) were obtained from conditional logistic regression models in which ever- users of the other tobacco product (either hookah or nass) and of cigarette were excluded. P for trend was obtained from the same models by assigning consecutive numbers to categories within each categorical variable. Cumulative use was calculated by multiplying intensity of use (per day) by duration of use (in years). Numbers may not add up to the total numbers due to missing data in some variables. Adjusted ORs (95% CIs) were adjusted for age, ethnicity, religion, place of residence, education level, and ever-use of gutka, bidi, cannabis, and alcohol, and daily fruit and fresh vegetable consumption.