Pro-Inflammatory Diet as a Risk Factor for Stomach Cancer: Findings from a Multicenter Study in Central and Western China

Figures & data

Table 1 Comparison of General Clinical Data of Participants with Gastric Mucosal Diseases

Variable	Chronic Gastritis Group (n=668)	Precancerous Lesions Group (n=411)	Stomach Cancer Group (n=83)	χ²	p-value
Sociodemographic characteristics
Age, (Q2 〔Q1, Q3〕)	48〔39, 56〕	54〔46, 59〕	60〔53, 68〕	100.081	< 0.001
BMI, (Q2 〔Q1, Q3〕)	22.41〔20.20, 24.83〕	22.65〔20.20, 25.10〕	21.88〔19.59, 23.67〕	5.816	0.055
Female, n (%)	336 (50.3)	166 (40.4)	28 (33.7)	15.155	0.001
Race, n (%)				4.935	0.085
Han	617 (92.4)	393 (95.6)	76 (91.6)
Others	51 (7.6)	18 (4.4)	7 (8.4)
Residence, n (%)				36.750	< 0.001
City	387 (57.9)	248 (60.3)	24 (28.9)
Township	98 (14.7)	58 (14.1)	12 (14.5)
Rural	183 (27.4)	104 (25.3)	47 (56.6)
Character, n (%)				13.178	0.010
Introverted	222 (33.2)	162 (39.4)	37 (44.6)
Intermediate	292 (43.7)	158 (38.4)	21 (25.3)
Extrovert	154 (23.1)	91 (22.2)	25 (30.1)
Education, n (%)				54.193	< 0.001
Primary School	136 (20.4)	99 (24.1)	42 (50.6)
Middle School	273 (40.9)	189 (46.0)	35 (42.2)
University and Above	259 (38.8)	123 (29.9)	6 (7.2)
Blood Type, n (%)				18.262	0.019
A	81 (12.1)	59 (14.3)	6 (7.2)
B	112 (16.8)	57 (13.9)	7 (8.4)
O	109 (16.3)	79 (19.2)	17 (20.5)
AB	45 (6.7)	33 (8.0)	5 (6.0)
Unknown	321 (47.5)	183 (44.0)	48 (57.8)
Profession, n (%)				27.790	< 0.001
Farmers	196 (29.4)	155 (37.7)	47 (56.6)
Others	472 (61.8)	256 (33.5)	36 (4.7)
Income (RMB), n (%)				22.479	< 0.001
Lower (< 5000)	187 (28.0)	145 (35.3)	42 (50.6)
Middle (5000–10,000)	427 (63.9)	235 (57.2)	40 (48.2)
Higher (> 10,000)	54 (8.1)	31 (7.5)	1 (1.2)
Main Drinking Water, n (%)				47.316	< 0.001
Tap Water	597 (89.4)	332 (80.1)	55 (66.3)
Well Water	61 (9.1)	56 (13.6)	25 (30.1)
Rivers and Lakes	10 (1.5)	23 (5.6)	3 (3.6)
Clinical features
Disease history, n (%)
Hypertension	57 (8.5)	44 (10.7)	11(13.3)	2.720	0.257
Diabetes	23 (3.4)	15 (3.6)	3 (3.6)	0.034	0.983
Immune diseases	8 (1.2)	6 (1.5)	3 (3.6)	2.991	0.326
Medical history, n (%)
NSAIDS	12 (1.8)	4 (1.0)	1 (1.2)	1.237	0.523
Aspirin	8 (1.2)	3 (0.7)	2 (2.4)	1.850	0.445
Metformin	16 (2.4)	11 (2.7)	2 (2.4)	0.085	0.959
Statin	3 (1.2)	5 (1.2)	1 (0.4)	2.165	0.342
Daily habit
High Salt Diet, n (%)	156 (23.4)	113 (27.5)	36 (43.4)	15.796	< 0.001
Smoking status, n (%)				27.201	< 0.001
Never smoker	467 (69.9)	245 (59.6)	37 (44.6)
Past smoker or Current smoker	201 (30.1)	166 (40.4)	46 (55.4)
Family History of Stomach Cancer, n (%)	58 (8.7)	66 (16.1)	15 (18.1)	15.599	< 0.001
Hp infection, n (%)	310 (46.4)	232 (56.4)	37 (44.6)	11.246	0.004
DII score, (Q2 〔Q1, Q3〕)	0.030 (−0.840, 0.705)	0.200 (−0.920, 0.460)	0.030 (−0.92, 0.46)	9.945	0.007

Notes: statistical analyses were performed on the age, BMI and DII score variables using the Kruskal Wallis H-rank sum test, while the other variables were tested using the chi-square test. A statistically significant difference was defined as p-value < 0.05. The chronic gastritis group includes chronic gastritis and atrophic gastritis; The precancerous lesions group includes atrophic gastritis with intestinal metaplasia and dysplasia.

Abbreviations: Q1, First quartile; Q2, Second quartile; Q3, Third quartile; BMI, body mass index; RMB, Rén mín bì’; HP, Helicobacter pylori; DII, Dietary Inflammatory Index.

Figure 1 Research flowchart.

Table 2 Single-Factor Analysis of Risk Factors for Stomach Cancer

Variable	Non-Stomach Cancer Group (n=1079)	Stomach Cancer Group (n=83)	χ^2	p-value
Age (years old)			34.347	<0.001
18–51	581 (53.8)	17 (20.5)
52–75	498	66
Gender, Men, n (%)	577 (53.5)	55(66.5)	5.082	0.024
Residence, n (%)			36.432	<0.001
City	635 (58.9)	24 (28.9)
Township	156 (14.5)	12 (14.5)
Rural	288 (26.7)	47 (56.6)
Character, n(%)			8.789	0.032
Introverted	384 (35.6)	37 (44.6)
Intermediate	450 (41.7)	21 (25.3)
Extrovert	244 (22.7)	25 (30.1)
Education, n(%)			45.189	<0.001
Primary School	235 (21.8)	42 (50.6)
Middle School	462 (42.8)	35 (42.2)
University and Above	382 (35.4)	6 (7.2)
Blood Type, n(%)			7.974	0.537
A	139 (12.9)	6 (7.2)
B	169 (15.7)	7 (8.4)
O	188 (17.4)	17 (20.5)
AB	78 (7.2)	5 (6)
Unknown	505 (46.9)	48 (57.8)
Profession n(%)			19.872	<0.001
Farmers	357 (32.5)	47 (56.6)
Others	728 (67.5)	36 (43.4)
Income (RMB), n (%)			16.266	<0.001
Lower (< 5000)	332 (30.8)	42 (50.6)
Middle (5000–10,000)	662 (61.4)	40 (48.2)
Higher (> 10,000)	85 (7.9)	1 (1.2)_
Main Drinking Water, n (%)			27.094	<0.001
Tap Water	929 (86.1)	55 (66.3)
Well Water	117 (10.8)	25 (30.1)
Rivers and Lakes	33 (3.1)	3 (3.6)
High Salt Diet, n(%)	269 (24.9)	36 (43.4)	13.679	0.003
Family History of Stomach Cancer, n(%)	124 (11.5)	15 (18.1)	3.503	0.623
Hp infection, n(%)	542 (50.2)	37 (44.6)	1.363	0.506
Smoking status, n(%)			16.132	0.003
Never smoker	711 (65.9)	37 (44.6)
Past smoker or Current smoker	114 (10.6)	12 (41)
Pro-inflammatory diet, n(%)	342 (31.7)	59 (71.1)	52.907	<0.001

Notes: Statistical single factor analysis of stomach cancer risk factors using chi square test. A statistically significant difference was defined as p-value < 0.05. The non-stomach cancer group includes chronic gastritis group and precancerous lesions group.

Abbreviations: RMB, Rén mín bì’; HP, Helicobacter pylori.

Table 3 Multivariate Analysis of Risk Factors for Stomach Cancer

Variable	β	SE	Wald χ^2	OR (95% CI)	p-value
Age, (ref: ≤51 years old)	1.325	0.298	19.715	3.763 (2.096–6.754)	< 0.001
Residence, (ref: city)	0.530	0.150	12.418	1.699 (1.265–2.282)	< 0.001
Education level, (ref: primary school)	−0.954	0.216	19.544	0.385 (0.259–0.606)	< 0.001
Smoking status, (ref: never smoker)	0.889	0.274	12.069	2.433 (1.473–4.019)	0.001
Pro-inflammatory diet: (ref: anti-inflammatory diet)	2.002	0.274	53.370	7.400 (4.4326–12.661)	< 0.001
Constant	−6.377	0.877	52.823	0.002	< 0.001

Notes: Binary Logistic analysis, forwardL: LR method is used to screen independent variables, αin=0.05, αout=0.10.

Abbreviations: β, regression coefficient; SE, Standard Error; OR, Odds Ratio; CI, Confidence Intervals.

Figure 2 Relationship between stomach cancer and gastrointestinal symptoms.

Figure 3 The correlation between pro-inflammatory diet and the severity of gastric mucosal diseases.