Table 3

Univariate analysis for the PV, IPSS and IIEF-5 score

	PV		IPSS		IIEF-5
Variables	Means±SDs	p Value	Means±SDs	p Value	Medians (q1, q3)	p Value
Education (years)
≤9	35.3±20.6		17.84±6.50		8 (1, 14)
>9	32.9±19.1	0.007	16.05±6.21	<0.001	10 (2, 15)	0.001
Smoking
No	33.2±19.4		16.14±6.02		8 (1, 14)
Yes	34.1±19.7	0.250	17.04±6.49	<0.001	10 (2, 15)	0.070
Alcohol consumption
No	33.4±19.3		16.32±6.21		9 (1, 15)
Yes	33.8±19.9	0.600	16.80±6.54	0.066	10 (2, 16)	0.002
Region
Northern China	33.1±19.0		16.44±6.37		9 (1, 15)
Southern China	39.6±20.8		14.84±5.95		10 (3, 16)
Northwestern China	28.8±19.2	<0.001	18.65±5.96	<0.001	8 (5, 12)	<0.001
	β (95% CI)	p	β (95% CI)	p	β (95% CI)	p
Age (years)	0.44 (0.35 to 0.52)	<0.001	0.14 (0.11 to 0.16)	<0.001	−0.35 (−0.38 to −0.32)	<0.001
BMI (kg/m²)	0.48 (0.24 to 0.71)	<0.001	0.10 (0.03 to 0.18)	0.008	−0.20 (−0.28 to −0.12)	<0.001
Meat, fish and eggs (times/week)	−0.01 (−0.25 to 0.26)	0.961	−0.13 (−0.21 to −0.05)	0.002	0.01 (−0.01 to 0.02)	0.269
Vegetables (times/week)	0.82 (0.47 to 1.16)	<0.001	0.09 (−0.02 to 0.21)	0.098	−0.04 (−0.06 to −0.02)	<0.001
Milk and dairy products (times/week)	−0.02 (−0.10 to 0.14)	0.743	0.05 (0.01 to 0.09)	0.010	−0.01 (−0.20 to −0.01)	<0.001

Means and SDs were used to present normally distributed continuous variables, and medians (q1, q3) were used to present non-normally distributed variables (IIEF-5 score).
Categorical variables (education, smoking, alcohol consumption and region): t-test or one-way ANOVA was used for PV and IPSS; Wilcoxon test or Kruskal-Wallis test was used for the IIEF-5 score.
Continuous variables (age, BMI and diet): univariate linear regressions was used for PV, IPSS and the IIEF-5 score.
β: Unstandardised coefficients.
ANOVA, analysis of variance; BMI, body mass index; IIEF-5, International Index of Erectile Function 5; IPSS, International Prostate Symptom Score; PV, prostate volume.