Table S7. Subgroup analyses for three plant-based diet indices and risks of EC.

Variables	PDI				uPDI				hPDI
	HR (95% CI)*	P	Pinteraction		HR (95% CI)*	P	Pinteraction		HR (95% CI)*	P	Pinteraction
PDI, overall plant-based diet index; EC, esophageal cancer; uPDI, unhealthful plant-based diet index; hPDI, healthful plant-based diet index; HR, hazard ratio; 95% CI, 95% confidence interval; *, HR for quartiles of PDI, hPDI, and uPDI. The HR and 95% CI of Quartiles 2, 3, 4 were calculated with reference to Quartile 1.
Gender
Male	1.00				1.00				1.00
	0.86 (0.54−1.38)	0.528			1.21 (0.70−2.09)	0.499			0.72 (0.46−1.15)	0.170
	0.91 (0.57−1.46)	0.703			1.25 (0.70−2.24)	0.452			0.63 (0.38−1.07)	0.089
	0.66 (0.36−1.20)	0.173			1.71 (0.99−2.93)	0.053			0.56 (0.32−0.97)	0.040
Female	1.00		0.848		1.00		0.123		1.00		0.935
	1.19 (0.58−2.45)	0.626			0.93 (0.41−2.12)	0.863			0.57 (0.29−1.12)	0.103
	1.14 (0.54−2.38)	0.730			2.63 (1.26−5.48)	0.010			0.54 (0.27−1.08)	0.082
	1.15 (0.51−2.58)	0.736			2.09 (0.94−4.64)	0.070			0.39 (0.18−0.81)	0.012
Age at baseline (year)
40−49	1.00								1.00
	0.82 (0.35−1.94)	0.658			−	−			0.96 (0.45−2.05)	0.926
	0.59 (0.23−1.54)	0.284			−	−			0.60 (0.23−1.54)	0.289
	1.00 (0.39−2.53)	0.999			−	−			0.18 (0.04−0.79)	0.023
50−59	1.00		0.397		1.00		−		1.00		0.188
	1.01 (0.59−1.73)	0.966			1.01 (0.54−1.87)	0.981			0.63 (0.38−1.04)	0.073
	1.33 (0.80−2.22)	0.278			1.76 (0.96−3.20)	0.067			0.57 (0.33−0.98)	0.044
	0.84 (0.44−1.63)	0.614			2.11 (1.19−3.77)	0.011			0.45 (0.25−0.81)	0.007
60−69	1.00				1.00				1.00
	0.99 (0.46−2.15)	0.980			0.49 (0.20−1.20)	0.116			0.52 (0.20−1.35)	0.181
	0.60 (0.25−1.45)	0.253			1.00 (0.44−2.28)	0.994			0.74 (0.30−1.83)	0.519
	0.50 (0.16−1.56)	0.234			0.58 (0.22−1.48)	0.254			1.04 (0.46−2.34)	0.930
Marital status
Married	1.00				1.00				1.00
	1.04 (0.69−1.58)	0.836			1.22 (0.76−1.97)	0.415			0.69 (0.46−1.04)	0.073
	1.01 (0.66−1.54)	0.964			1.85 (1.15−2.99)	0.012			0.62 (0.40−0.95)	0.030
Unmarried/divorced/ widowed	0.90 (0.55−1.47)	0.673			1.94 (1.21−3.12)	0.006			0.48 (0.30−0.76)	0.002
	−	−	−		−	−	−		−	−	−
	−	−			−	−			−	−
	−	−			−	−			−	−
Educational status
Elementary school and below	1.00				1.00				1.00
	0.90 (0.50−1.62)	0.721			1.09 (0.59−1.99)	0.784			0.60 (0.32−1.10)	0.098
	1.00 (0.56−1.78)	0.994			1.48 (0.80−2.75)	0.215			0.77 (0.43−1.39)	0.386
	0.77 (0.38−1.56)	0.473			0.98 (0.50−1.92)	0.952			0.62 (0.34−1.13)	0.118
Middle school and above	1.00		0.965		1.00		0.093		1.00		0.435
	0.98 (0.58−1.66)	0.935			1.22 (0.62−2.43)	0.564			0.74 (0.45−1.20)	0.221
	0.91 (0.53−1.58)	0.743			1.97 (1.00−3.89)	0.049			0.49 (0.27−0.89)	0.020
	0.80 (0.42−1.54)	0.509			2.95 (1.56−5.60)	0.001			0.40 (0.21−0.78)	0.007
No. of family members
1−3	1.00				1.00				1.00
	1.06 (0.60−1.90)	0.835			0.94 (0.51−1.75)	0.853			0.77 (0.43−1.39)	0.389
	1.06 (0.58−1.92)	0.854			1.24 (0.66−2.33)	0.507			0.81 (0.44−1.48)	0.489
	0.91 (0.45−1.84)	0.785			1.09 (0.56−2.11)	0.793			0.82 (0.44−1.51)	0.519
4−6	1.00		0.970		1.00		0.263		1.00		0.197
	0.88 (0.52−1.50)	0.639			1.36 (0.70−2.65)	0.365			0.63 (0.38−1.04)	0.071
	0.92 (0.54−1.57)	0.773			2.32 (1.20−4.49)	0.012			0.48 (0.27−0.85)	0.013
	0.72 (0.37−1.37)	0.317			2.73 (1.45−5.14)	0.002			0.31 (0.16−0.60)	0.001
Annual income (CNY/person)
≤5,000	1.00				1.00				1.00
	1.06 (0.58−1.94)	0.859			0.77 (0.38−1.54)	0.462			0.59 (0.31−1.11)	0.101
	0.99 (0.53−1.85)	0.985			0.86 (0.41−1.78)	0.676			0.62 (0.32−1.22)	0.168
	0.75 (0.33−1.70)	0.490			1.29 (0.67−2.49)	0.452			0.63 (0.32−1.23)	0.176
>5,000	1.00		0.912		1.00		0.189		1.00		0.746
	0.87 (0.52−1.45)	0.587			1.44 (0.79−2.62)	0.239			0.73 (0.45−1.18)	0.203
	0.92 (0.55−1.54)	0.762			2.50 (1.38−4.53)	0.002			0.61 (0.36−1.05)	0.075
	0.80 (0.44−1.45)	0.460			2.18 (1.19−3.99)	0.012			0.43 (0.24−0.78)	0.005
BMI (kg/m2)
<23.9	1.00				1.00				1.00
	0.97 (0.61−1.56)	0.906			1.19 (0.70−2.01)	0.526			0.77 (0.48−1.24)	0.275
	0.89 (0.54−1.45)	0.631			1.30 (0.74−2.28)	0.357			0.84 (0.52−1.38)	0.499
	0.85 (0.48−1.50)	0.581			1.49 (0.86−2.56)	0.153			0.63 (0.37−1.08)	0.090
≥24	1.00		0.808		1.00		0.082		1.00		0.098
	0.90 (0.45−1.81)	0.770			0.89 (0.36−2.19)	0.793			0.54 (0.28−1.03)	0.063
	1.15 (0.59−2.25)	0.673			2.61 (1.17−5.80)	0.019			0.27 (0.11−0.65)	0.004
	0.70 (0.28−1.70)	0.426			2.58 (1.16−5.72)	0.020			0.33 (0.15−0.72)	0.005
Smoking status
Yes	1.00				1.00				1.00
	0.86 (0.48−1.52)	0.597			1.52 (0.70−3.31)	0.289			0.86 (0.49−1.50)	0.596
	0.66 (0.35−1.26)	0.208			1.42 (0.62−3.25)	0.408			0.53 (0.26−1.10)	0.090
	0.74 (0.34−1.58)	0.433			1.91 (0.89−4.11)	0.098			0.33 (0.13−0.83)	0.019
No	1.00		0.562		1.00		0.323		1.00		0.354
	1.06 (0.62−1.81)	0.831			0.90 (0.51−1.60)	0.718			0.57 (0.33−0.96)	0.035
	1.23 (0.73−2.07)	0.428			1.84 (1.07−3.16)	0.028			0.64 (0.38−1.08)	0.094
	0.89 (0.48−1.65)	0.704			1.76 (1.01−3.09)	0.047			0.57 (0.34−0.96)	0.034
History of digestive diseases
Yes	1.00				1.00				1.00
	0.70 (0.25−1.99)	0.506			0.46 (0.11−1.87)	0.277			0.17 (0.02−1.34)	0.093
	0.63 (0.21−1.89)	0.407			0.60 (0.15−2.49)	0.486			0.95 (0.33−2.75)	0.925
	0.32 (0.07−1.52)	0.152			1.54 (0.53−4.51)	0.427			0.67 (0.21−2.13)	0.493
No	1.00		0.578		1.00		0.207		1.00		0.194
	1.01 (0.66−1.54)	0.962			1.26 (0.77−2.05)	0.355			0.73 (0.49−1.09)	0.125
	1.05 (0.68−1.60)	0.839			1.88 (1.15−3.07)	0.012			0.58 (0.36−0.91)	0.018
	0.92 (0.55−1.52)	0.740			1.82 (1.11−2.98)	0.018			0.48 (0.30−0.77)	0.003
Family history of cancer
Yes	1.00				1.00				1.00
	1.16 (0.55−2.45)	0.700			0.99 (0.43−2.31)	0.989			0.59 (0.29−1.18)	0.137
	1.41 (0.68−2.92)	0.362			1.90 (0.86−4.22)	0.114			0.66 (0.33−1.33)	0.245
	1.52 (0.68−3.40)	0.310			2.16 (1.00−4.67)	0.049			0.44 (0.20−0.97)	0.042
No	1.00		0.214		1.00		0.690		1.00		0.916
	0.90 (0.57−1.42)	0.649			1.17 (0.69−2.01)	0.558			0.73 (0.46−1.16)	0.180
	0.82 (0.51−1.32)	0.421			1.56 (0.90−2.72)	0.114			0.60 (0.35−1.00)	0.052
	0.57 (0.31−1.05)	0.071			1.61 (0.93−2.80)	0.087			0.53 (0.31−0.91)	0.022