Mediterranean dietary components are inversely associated with advanced colorectal polyps: A case-control study

Table 1 Comparison between cases of advanced polyps and non-advanced adenomas versus controls in demographic, clinical and dietary parameters

	Controls (n = 385)	Cases with non-advanced adenomas (n = 192)	P value	Cases with advanced polyps (n = 206)	P value
Age (yr)	58.2 ± 6.6	58.8 ± 6.6	0.069	59.7 ± 6.0	0.022
Gender (% male)	47.9	56.2	0.061	58.1	0.010
Low socio-economic status1 (%)	7.2	8.6	0.410	8.6	0.846
1st degree Family history of CRC (%)	7.6	12.0	0.097	5.8	0.451
Physical inactivity2 (%)	44.3	45.2	0.988	50.3	0.171
Smoking (ever) (%)	48.4	62.5	0.017	60.7	0.002
BMI (kg/m2)	27.0 ± 5.1	29.1 ± 5.2	0.009	29.2 ± 6.1	0.004
Total calories (Kcal)	2013 ± 688	2063 ± 1045	0.652	2006 ± 724	0.804
Colonoscopy indication
Screening (%)	59.5	34.4	< 0.001	37.9	< 0.001
Diagnostic3 (%)	35.6	33.3	0.491	37.9	0.583
Surveillance4 (%)	0.0	32.3	< 0.001	24.3	< 0.001
Medication use
Statins (%)	41.1	47.4	0.046	49.7	0.091
Aspirin (%)	28.2	37.0	0.006	38.2	0.019
NSAIDs (%)	1.0	0.5	0.112	0.5	0.923
Antidiabetic medication (%)	10.8	9.9	0.923	13.1	0.654
Dietary intake
Number of MD components	5.1 ± 1.7	5.0 ± 1.9	0.620	4.5 ± 1.9	< 0.001
Beneficial components
Whole grains (servings/d)	2.2 ± 2.2	2.1 ± 1.9	0.884	1.7 ± 2.0	0.027
Vegetables and legumes (servings/d)	3.3 ± 2.0	3.4 ± 2.4	0.378	3.1 ± 2.1	0.185
Fruit (servings/d)	2.7 ± 2.3	2.2 ± 2.2	0.122	2.3 ± 2.4	0.227
Nuts and seeds (servings/d)	1.5 ± 1.6	1.5 ± 1.5	0.358	1.5 ± 1.7	0.355
MUFA/SFA ratio (per day)	1.4 ± 0.5	1.3 ± 0.5	0.298	1.3 ± 0.4	0.098
Fish (servings/wk)	3.9 ± 3.6	3.5 ± 3.8	0.378	3.4 ± 3.1	0.177
Poultry (servings/wk)	6.7 ± 5.1	6.8 ± 5.3	0.688	6.6 ± 4.5	0.462
Detrimental components
Alcoholic beverage (servings/d)	1.1 ± 0.5	1.1 ± 0.7	0.925	1.1 ± 0.6	0.179
Sugar sweetened beverages (servings/d)	3.1 ± 3.2	3.0 ± 3.4	0.827	3.3 ± 3.6	0.277
Red meat (servings/wk)	2.6 ± 4.1	3.2 ± 4.1	0.039	3.4 ± 4.1	0.036

¹Low socio-economic status - categorized as the lowest quartiles of education or income;

²Physical inactivity - categorized as reported physical activity of less than 20 min per week;

³Diagnostic colonoscopy - indicated by alarming symptoms such as anemia, unexplained weight loss, rectal bleeding, abdominal pain or change in bowel habits;

⁴Surveillance colonoscopy - indicated by familial or personal history of colorectal polyps. Continuous variables are presented as mean ± SD, and categorical variables as proportions. CRC: Colorectal cancer; BMI: Body mass index; NSAIDS: Non-steroidal anti-inflammatory drugs; MD: Mediterranean diet.

Table 2 Adjusted association between the Mediterranean dietary pattern score and its components and non-advanced or advanced colorectal polyps

1Dietary parameter	Non Advanced adenomas ( n = 192)			Advanced colorectal polyps (n = 206)
	Model 1OR (95%CI)P value	Model 2OR (95%CI)P value	Model 3OR (95%CI)P value	Model 1OR (95%CI)P value	Model 2OR (95%CI)P value	Model 3OR (95%CI)P value
MD score (per 1 point increase)	0.96 (0.87-1.07) 0.833	0.93 (0.83-1.05) 0.279	-	0.82 (0.75-0.91) < 0.001	0.80 (0.72-0.89) < 0.001	-
MD score
> 5	1 (ref)	1 (ref)	-	1 (ref)	1 (ref)	-
≤ 5	1.14 (0.78-1.67) 0.492	1.08 (0.70-1.64) 0.72		0.62 (0.43-0.90) 0.012	0.56 (0.39-0.87) 0.009
Whole grains (servings/d)
≤ 1.00	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 1.00	1.08 (0.74-1.58) 0.656	1.10 (0.74-1.64) 0.628	0.91 (0.58-1.40) 0.673	0.64 (0.45-0.91) 0.014	0.59 (0.40-0.85) 0.005	0.72 (0.48-1.09) 0.122
Vegetables and legumes (servings/d)
≤ 2.60	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 2.60	1.03 (0.71-1.50) 0.866	1.13 (0.73-1.73) 0.578	1.12 (0.69-1.80) 0.64	0.83 (0.58-1.17) 0.301	0.88 (0.59-1.31) 0.544	1.08 (0.69-1.69) 0.716
Fruit (servings/d)
≤ 1.50	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 1.50	0.79 (0.54-1.15) 0.225	0.77 (0.50-1.17) 0.229	0.93 (0.59-1.46) 0.751	0.61 (0.43-0.87) 0.007	0.60 (0.40-0.90) 0.013	0.70 (0.57-1.30) 0.107
Nuts and seeds (servings/d)
≤ 0.37	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 0.37	1.52 (1.04-2.24) 0.031	1.44 (0.96-2.18) 0.077	1.53 (0.96-2.44) 0.068	0.88 (0.62-1.25) 0.489	0.86 (0.59-1.25) 0.445	0.94 (0.62-1.43) 0.798
MUFA/SFA ratio (per day)
≤ 0.96	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 0.97	NA	0.82 (0.55-1.22) 0.337	0.73 (0.47-1.14) 0.171	1.04 (1.00-1.07) 0.017	0.81 (0.56-1.17) 0.263	0.86 (0.57-1.30) 0.478
Fish (servings/wk)
≤ 2.42	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 2.42	0.80 (0.53-1.17) 0.258	0.80 (0.53-1.20) 0.294	0.70 (0.45-1.09) 0.117	0.69 (0.48-0.98) 0.039	0.65 (0.44-0.94) 0.025	0.66 (0.44-0.99) 0.047
Poultry (servings/wk)
≤ 5.00	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
> 5.00	1.20 (0.82-1.76) 0.343	1.06 (0.70-1.61) 0.767	1.07 (0.69-1.65) 0.759	0.90 (0.63-1.27) 0.559	0.85 (0.59-1.25) 0.428	0.75 (0.50-1.11) 0.157
Alcoholic beverage (servings/d)
> 0.75	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
≤ 0.75	0.81 (0.55-1.20) 0.304	0.78 (0.51-1.17) 0.235	0.83 (0.53-1.29) 0.411	1.18 (0.82-1.69) 0.357	1.18 (0.81-1.74) 0.377	1.17 (0.78-1.76) 0.438
Sugar sweetened beverages (servings/d)
> 0.20	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
≤ 0.20	1.14 (0.78-1.67) 0.474	1.04 (0.68-1.58) 0.856	1.12 (0.70-1.77) 0.622	0.63 (0.44-0.90) 0.012	0.56 (0.37-0.83) 0.005	0.56 (0.36-0.87) 0.010
Red meat (servings/wk)
> 1.17	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)	1 (ref)
≤ 1.17	0.63 (0.42-0.93) 0.021	0.60 (0.40-0.91) 0.017	0.56 (0.35-0.88) 0.013	0.71 (0.49-0.97) 0.039	0.66 (0.45-0.96) 0.033	0.63 (0.42-0.95) 0.031

Model 1 - OR are adjusted for age (years), gender and BMI (kg/m²); Model 2 - OR are adjusted for: parameters of Model 1 and smoking (ever), use of aspirin, NSAIDs, statin and antidiabetic medication, daily caloric intake (kcal) and colonoscopy indication (screening, diagnostic or surveillance); Model 3 - OR are adjusted for: parameters of Model 2 and for all other dietary components.

¹The cutoffs for the MD and for each dietary factor was based on the sample median, with the exception of the MD score (per 1 point increase) which ranged from zero to ten. Vegetables and legumes: Fresh/cooked; Fruit: Fresh whole fruit; Nuts and seeds: Natural unsalted nuts and seeds or paste products; Whole grains: Bread, cooked grains, breakfast cereal; Fish: Fresh, canned and cooked. Ratio of mono-unsaturated fatty-acids to saturated fatty-acids (MUFA/SFA); Poultry: Chicken and turkey products; Red meat: Beef, veal, pork products and internal organs; Alcohol: Beer, wine, liquor; Sugar-sweetened beverages: Fruit juice, iced tea, non-diet soft drinks. BMI: Body mass index; NSAIDS: Non-steroidal anti-inflammatory drugs; MD: Mediterranean diet.