Association between gaseous air pollutants and idiopathic nephrotic syndrome in children: a 12-year population-based cohort study

Table 2 Differences in nephrotic syndrome incidences and associated HRs in participants exposed to various daily average concentrations of air pollutants in 2000–2012

Year 2000–2012	Event	PY^a	IR^b	cHR^c	95%CI	aHR^d	95% CI^e
SO₂
Quartile 1, < 3.38 ppb	33	431,707	0.76	Reference group		Reference group
Quartile 2, 3.38–4.32 ppb	39	589,450	0.66	0.87	(0.55, 1.38)	0.89	(0.56, 1.42)
Quartile 3, 4.32–6.03 ppb	83	914,846	0.91	1.19	(0.80, 1.78)	1.24	(0.82, 1.87)
Quartile 4, > 6.03 ppb	109	826,014	1.32	1.73	(1.17, 2.55)**	1.78	(1.20,2.64)**
THC
Quartile 1, < 2.29 ppm	31	780,924	0.40	Reference group		Reference group
Quartile 2, 2.29–2.38 ppm	48	583,193	0.82	2.08	(1.32, 3.26)**	2.09	(1.33, 3.29)**
Quartile 3, 2.38–2.60 ppm	121	889,830	1.36	3.47	(2.34, 5.16)***	3.61	(2.42,5.37)***
Quartile 4, > 2.60 ppm	64	508,071	1.26	3.25	(2.12, 5.00)***	3.49	(2.24,5.42)***
CH4
Quartile 1, < 2.01 ppm	23	708,759	0.32	Reference group		Reference group
Quartile 2, 2.01–2.06 ppm	30	765,925	0.39	1.20	(0.70, 2.07)	1.21	(0.70, 2.08)
Quartile 3, 2.06–2.11 ppm	77	726,349	1.06	3.29	(2.06, 5.24)***	3.33	(2.09,5.31)***
Quartile 4, > 2.11 ppm	134	560,985	2.39	7.68	(4.93, 12.0)***	7.83	(5.02,12.2)***

^aPY person-years, ^bIR incidence rate, (per 10,000 person-years), ^ccHR crude hazard ratio, ^daHR adjusted hazard ratio, adjustment for age, sex, monthly income, and urbanization level, ^eCI confidence interval; **p < 0.01; *** p < 0.001

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