Table 5.

Adjusted PRs of birth weight < 3,000 g according to the estimated exposure levels, for trimester-specific exposure windows, among 1,016 singleton children from the LISA cohort.

	1st trimester			2nd trimester		3rd trimester
Air pollutant level	No.	PRa	95% CIb	PRa	95% CIb	PRa	95% CIb
PM2.5
Each trimester separately
1st quartile (lowest)	245	1		1		1
2nd quartile	246	1.14	0.74–1.96	0.83	0.52–1.32	1.30	0.80–2.17
3rd quartile	249	1.28	0.84–2.10	1.08	0.71–1.60	1.44	0.85–2.27
4th quartile	247	1.65	1.02–2.60	0.94	0.61–1.47	1.90	1.20–2.82
Continuous coding (increase of 1 μg/m3)	987	1.10	0.99–1.20	1.01	0.92–1.12	1.14	1.02–1.24
All trimesters togetherc
1st quartile	245	1		1		1
2nd quartile	246	0.97	0.60–1.73	0.75	0.46–1.24	1.34	0.79–2.30
3rd quartile	249	0.98	0.57–1.75	0.86	0.56–1.30	1.48	0.86–2.58
4th quartile	247	1.22	0.71–2.18	0.75	0.48–1.23	1.91	1.00–3.20
Continuous coding (increase of 1 μg/m3)	987	1.03	0.90–1.17	0.94	0.84–1.06	1.14	0.99–1.29
PM2.5 absorbance
Each trimester separately
1st quartile	249	1		1		1
2nd quartile	243	1.15	0.73–1.80	1.33	0.85–2.22	1.30	0.85–2.09
3rd quartile	248	1.01	0.61–1.53	1.76	1.07–2.91	0.92	0.55–1.50
4th quartile	247	1.04	0.70–1.57	1.83	1.11–2.81	1.50	1.00–2.27
Continuous coding (increase of 0.5 × 10−5/m)	987	1.03	0.82–1.28	1.27	1.04–1.54	1.20	0.98–1.44
All trimesters togetherc
1st quartile	249	1		1		1
2nd quartile	243	0.90	0.52–1.58	1.30	0.77–2.16	0.99	0.64–1.62
3rd quartile	248	0.82	0.45–1.31	1.63	0.93–2.73	0.71	0.40–1.20
4th quartile	247	0.88	0.53–1.42	1.99	1.12–3.33	1.14	0.68–1.91
Continuous coding (increase of 0.5 × 10−5/m)	987	1.02	0.77–1.29	1.21	0.93–1.54	1.15	0.92–1.42
NO2
Each trimester separately
1st quartile	248	1		1		1
2nd quartile	248	1.01	0.67–1.57	0.99	0.62–1.54	1.17	0.73–1.95
3rd quartile	248	1.07	0.71–1.60	1.30	0.79–2.00	1.05	0.64–1.75
4th quartile	243	0.86	0.53–1.30	1.35	0.88–2.11	1.42	0.91–2.22
Continuous coding (increase of 10 μg/m3)	987	0.96	0.73–1.20	1.18	0.95–1.44	1.13	0.91–1.35
All trimesters togetherc
1st quartile	248	1		1		1
2nd quartile	248	0.87	0.55–1.45	0.99	0.62–1.58	1.08	0.65–1.86
3rd quartile	248	1.00	0.60–1.64	1.25	0.76–2.02	0.90	0.52–1.62
4th quartile	243	0.81	0.45–1.36	1.38	0.80–2.34	1.25	0.72–2.09
Continuous coding (increase of 10 μg/m3)	987	0.92	0.67–1.22	1.19	0.93–1.51	1.06	0.82–1.30

^aPR of birth weight < 3,000 g adjusted for the same variables as in Table 3.

^bBootstrap CIs (bias-corrected and accelerated).

^cFor each pollutant, the models were adjusted simultaneously for the three trimester-specific exposure variables.