. 2017 Oct 13;125(10):107005. doi: 10.1289/EHP1742

Table 5.

Results from random-effects meta-analyses for the association between exposure to ${PM}_{2.5}$ and breast cancer incidence in 15 European cohorts: The sensitivity analyses.

${PM}_{2.5}$	$n$ Cohorts	$n$	HR (95% CI)	$I^{2}$ (p-value)^a
Main model	11	68,806	1.08 (0.77, 1.51)	56.7 (0.03)
Excluding VHM&PP (poor covariate adjustment)	10	55,419	1.28 (0.99, 1.65)	0.0 (0.71)
Including cohorts with all breast cancer risk factors (Model 3)	3^b	25,014	1.35 (0.96, 1.90)	0.0 (0.91)
Restricted to long-term residents	7^c	37,150	2.19 (0.29, 16.58)	75.9 ( $< 0.01$ )
Restricted to nonmovers	8^d	44,449	1.01 (0.22, 4.74)	62.8 (0.03)
Further adjustment for urbanization	9^e	57,286	1.20 (0.18, 7.86)	75.4 ( $< 0.01$ )
Variables that do not meet PH assumption as strata	11	68,806	1.21 (0.23, 6.40)	72.3 ( $< 0.01$ )
Excluding cohorts with $> 30 %$ of original cohort excluded	10^f	54,559	0.99 (0.67, 1.48)	64.5 (0.02)

Note: CEANS, Cardiovascular Effects of Air Pollution and Noise in Stockholm; CI, confidence interval; DCH, Danish Diet, Health and Cancer cohort; EPIC, European Prospective Investigation into Cancer and Nutrition; EPIC-E3N, French cohort of the Etude Epidemiologique de Femmes de la Mutuelle Générale de l'Education Nationale; HR, hazard ratio; HUBRO, Oslo Health Study; PH, proportional hazard; ${PM}_{2.5}$ , particulate matter $\leq 2.5 μ m$ ; VHM&PP, Vorarlberg Health Monitoring and Prevention Programme..

^{^a}

Cochran’s test for heterogeneity for Model 3 of effect estimates between the cohorts.

^{^b}

Three cohorts with information on PM and all breast cancer risk factors: DCH, EPIC-Varese, and EPIC-Turin.

^{^c}

Seven cohorts: HUBRO, CEANS (4 Swedish cohorts pooled), DCH, and VHM&PP.

^{^d}

Eight cohorts: HUBRO, CEANS (4 Swedish cohorts pooled), DCH, EPIC-Oxford, and VHM&PP.

^{^e}

Nine cohorts: CEANS (4 Swedish cohorts pooled), DCH, EPIC-Oxford, EPIC-Netherlands (2 Dutch cohorts pooled), and VHM&PP.

^{^f}

Ten cohorts: CEANS (4 Swedish cohorts pooled), DCH, EPIC-Oxford, EPIC-Netherlands (2 Dutch cohorts pooled), VHM&PP, EPIC-Turin.