Table 3. Stratified analyses of flavonoid subclasses and colorectal cancer risk.

Subgroup analysis		Pooled OR	95% CI	Heterogeneity I2 (%)	P Value
Flavones
Design	Case-control	0.83	(0.69,1.14)	75.6%	0.017
	Cohort	0.98	(0.88,1.08)	0	0598
Gender	Male	0.95	(0.87,1.05)	6.9%	0.342
	Female	0.95	(0.87,1.04)	0	0.564
Site of tumour	Colon	0.88	(0.68,1.13)	73.1%	0.011
	Rectum	0.82	(0.70,0.97)	0	0.608
Flavonols
Design	Case-control	0.70	(0.62,080)	0	0537
	Cohort	1.01	(0.91,1.23)	4.9%	0.349
Gender	Male	0.88	(0.77,1.01)	39.7%	0.191
	Female	0.87	(0.71,1.05)	80.4%	0.006
Site of tumour	Colon	0.784	(0.62,1.00)	67.1%	0.016
	Rectum	0.82	(0.63,1.08)	50.5%	0.089
Flavanones
Design	Case-control	1.14	(0.93,1.38)	42.5%	0.156
	Cohort	0.96	(0.84,1.10)	0	0.888
Gender	Male	1.00	(0.90,1.11)	0	0.581
	Female	0.98	(0.89,1.08)	0	0.716
Site of tumour	Colon	1.03	(0.92,1.15)	0	0.653
	Rectum	0.94	(0.80,1.11)	0	0.825
Flavanols
Design	Case-control	0.80	(0.64,0.99)	51.8%	0.101
	Cohort	1.01	(0.86,1.18)	41.3%	0.182
Gender	Male	1.06	(0.94,1.19)	36.3%	0.208
	Female	0.96	(0.86,1.07)	39.2%	0.193
Siteof tumour	Colon	0.88	(0.69,1.12)	68.3%	0.013
	Rectum	0.87	(0.74,1.02)	0	0.542
Anthocyanins
Design	Case-control	0.68	(0.56,0.83)	0	0.667
	Cohort	0.92	(0.67,1.28)	17%	0.272
Gender	Female	0.87	(0.66,1.13)	78.6%	0.009
	Male	0.89	(0.82,0.96)	0	0.862
Site of tumour	Colon	0.79	(0.61,1.02)	55.3%	0.107
	Rectum	0.88	(0.67,1.00)	72.3%	0.027
Isoflavones
Design	Case-control	0.85	(0.72,1.01)	71.3%	0.002
	Cohort	0.93	(0.83,1.04)	0	0.518
Gender	Male	0.920	(0.78,1.08)	50.5%	0.049
	Female	0.940	(0.84,1.06)	0	0.469
Site of tumour	Colon	0.86	(0.73,1.00)	35.4%	0.158
	Rectum	0.93	(0.78,1.10)	25.1%	0.237
Procyanidins
Design	Case-control	0.75	(0.66,0.86)	0	0.633
	Cohort	-*	-	-	-
Gender	Male	0.88	(0.80,0.98)	0	0.655
	Female	0.84	(0.74,0.96)	0	0.695
Site of tumour	Colon	0.81	(0.69,0.96)	0	0.555
	Rectum	0.66	(0.54,0.80)	0	0.522

^*no cohort studies were included in analysis for procyanidins.