The association between tuberculin skin test result and active tuberculosis risk of college students in Beijing, China: a retrospective cohort study

Table 2 Factors associated with active TB incidence in follow-up individuals

	# of individuals	TB events/follow-up person-years	IR^a(95% CI)	P for chi-square test	Univariate Cox regression		Multivariate Cox regression
	# of individuals	TB events/follow-up person-years	IR^a(95% CI)	P for chi-square test	HR (95% CI)	P value	Adjusted HR(95% CI)	P value
Sex				0.01
Female	30941	5/61881	8.08 (2.62~18.86)		Reference		Reference
Male	36351	21/72694	28.89 (17.88~44.17)		3.576 (1.348~9.483)	0.01	3.593 (1.354~9.537)	0.01
Ethnicity				0.86
Han	60086	23/120164	19.14 (12.12~28.73)		Reference		Reference
Others	7206	3/14411	20.82 (4.29~60.85)		1.088 (0.3266~3.622)	0.89
Region				0.21
East	33692	14/67377	20.78 (11.35~34.87)		Reference		Reference
Middle	17069	3/34138	8.79 (1.81~25.69)		0.423 (0.121~1.472)	0.17
West	16531	9/33060	27.22 (12.44~51.70)		1.310 (0.567~3.027)	0.52
TST response (induration size, mm)				< 0.001
0~4	51963	13/103923	12.51 (6.65~21.40)		Reference		Reference
5~9	7308	2/14615	13.68 (1.66~49.44)		1.094 (0.247~4.848)	0.91	1.094 (0.247~4.846)	0.91
10~14	4217	4/8431	47.44 (12.90~121.50)		3.794 (1.237~11.635)	0.02	3.644 (1.188~11.179)	0.02
15~19	2918	5/5834	85.70 (27.77~200.03)		6.853 (2.443~19.223)	< 0.001	6.832 (2.436~19.163)	< 0.001
≥ 20	886	2/1772	112.87 (13.66~407.79)		9.032 (2.038~40.025)	0.004	9.768 (2.203~43.315)	0.003

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