Obesity as a risk factor for early-onset colorectal cancer: Evidence from a nationally representative database

Table 1 Baseline characteristics of study participants

	Overall	Non eoCRC	eoCRC	P value
Number (n)	30321	30273	48
Age (year)	34.37 ± 8.61	34.36 ± 8.61	39.96 ± 7.61	< 0.001
Gender	16170 (53.3)	16146 (53.3)	24 (50.0)	0.751
Smoker	11945 (39.4)	11912 (39.3)	33 (68.8)	< 0.001
Heavy drinker	4493 (18.8)	4493 (18.8)	0 (0.0)	0.006
BRI quartile				0.002
Q1 (lowest)	10176 (34.7)	10171 (34.7)	5 (11.1)
Q2	7364 (25.1)	7350 (25.1)	14 (31.1)
Q3	5972 (20.4)	5963 (20.4)	9 (20.0)
Q4 (highest)	5827 (19.9)	5810 (19.8)	17 (37.8)
Waist circumference (cm)	96.44 ± 16.86	96.43 ± 16.86	105.73 ± 13.97	< 0.001
	14369 (49.0)	14337 (48.9)	32 (71.1)	0.005
BMI				0.028
Normal weight	9893 (32.6)	9886 (32.7)	7 (14.6)
Overweight	9519 (31.4)	9500 (31.4)	19 (39.6)
Obese	10909 (36.0)	10887 (36.0)	22 (45.8)
Height (cm)	168.21 ± 9.99	168.21 ± 9.99	169.22 ± 9.36	0.484
Weight (kg)	82.05 ± 22.61	82.04 ± 22.62	88.12 ± 18.09	0.063
BRI	5.06 ± 2.35	5.05 ± 2.35	6.19 ± 2.23	0.001
BMI	28.92 ± 7.30	28.92 ± 7.30	30.84 ± 6.43	0.068

Categorical variables were treated as factors and summarized as frequencies and percentages, while continuous variables were presented as mean ± SD or median (IQR), as appropriate. A comparison between groups were performed using Student’s t-test or Wilcoxon rank-sum test for continuous variables and χ² or Fisher’s exact test for categorical variables. P < 0.05 were considered as significant value. eoCRC: Early-onset colorectal cancer; BRI: Body roundness index; BMI: Body mass index.