Table 4.

Pooled difference in estimated leukocyte proportion ($\mathrm{\Delta }$; %) per $10{\text{-}\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$ increase in PM concentrations among $n=\mathrm{8,457}$ participants, Women’s Health Initiative (1993–2002) and Atherosclerosis Risk in Communities (1990–1995) study.

PM exposure	$\text{CD}{8}^{+}$ T cells		$\text{CD}{4}^{+}$ T cells		Natural killer cells		B cells		Monocytes		Granulocytes
	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b	$\mathrm{\Delta }$ % (95% CI)a	$p_{\text{Cochran}’\mathrm{s}Q}$b
${\mathrm{PM}}_{10}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)
2-d mean	0.1 ($-0.4$, 0.6)	0.15	$-0.1$ ($-0.4$, 0.2)	0.12	0.0 ($-0.2$, 0.3)	0.93	$-0.2$ ($-0.4$, 0.0)	0.46	0.0 ($-0.1$, 0.2)	0.49	0.1 ($-0.1$, 0.3)	0.69
7-d mean	0.3 ($-0.3$, 0.8)	0.28	$-0.2$ ($-0.5$, 0.1)	0.63	$-0.1$ ($-0.6$, 0.4)	0.18	$-0.4$ ($-0.7$, $-0.1$)	0.93	$-0.1$ ($-0.3$, 0.2)	0.49	$-0.2$ ($-0.5$, 0.2)	0.25
1-month mean	$-0.4$ ($-1.2$, 0.3)	0.30	0.0 ($-0.5$, 0.5)	0.26	$-0.3$ ($-1.0$, 0.4)	0.16	$-0.2$ ($-0.7$, 0.2)	0.64	0.2 ($-0.4$, 0.8)	0.06	0.4 ($-0.1$, 0.9)	0.28
12-month mean	$-0.5$ ($-1.4$, 0.4)	0.63	0.1 ($-0.5$, 0.6)	0.38	$-0.3$ ($-1.5$, 0.8)	0.14	$-0.5$ ($-1.1$, 0.2)	0.58	$-0.3$ ($-0.7$, 0.1)	0.41	0.0 ($-0.9$, 1.0)	0.13
${\mathrm{PM}}_{2.5}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)
1-month mean	$-1.1$ ($-1.9$, $-0.3$)	0.58	$-0.2$ ($-1.0$, 0.6)	0.18	$-0.6$ ($-2.2$, 1.0)	0.00	$-0.5$ ($-1.1$, 0.1)	0.72	$-0.1$ ($-0.5$, 0.3)	0.44	1.2 (0.6, 1.8)	0.75
12-month mean	$-1.3$ ($-2.4$, $-0.1$)	0.84	0.2 ($-0.7$, 1.2)	0.34	$-1.4$ ($-3.7$, 0.8)	0.03	$-0.9$ ($-1.9$, 0.2)	0.42	$-0.4$ ($-0.9$, 0.2)	0.65	1.1 ($-0.2$, 2.4)	0.25
${\mathrm{PM}}_{2.5–10}$ (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)
1-month mean	0.5 ($-0.9$, 1.8)	0.23	0.0 ($-0.6$, 0.6)	0.80	$-0.1$ ($-0.8$, 0.7)	0.63	$-0.2$ ($-0.9$, 0.5)	0.80	0.1 ($-0.7$, 0.8)	0.14	$-0.6$ ($-1.3$, 0.1)	0.33
12-month mean	0.0 ($-2.4$, 2.3)	0.13	$-0.2$ ($-1.0$, 0.6)	0.51	0.3 ($-0.9$, 1.4)	0.80	$-0.3$ ($-1.3$, 0.7)	0.71	$-0.2$ ($-0.9$, 0.4)	0.60	$-1.2$ ($-2.4$, 0.1)	0.17

Note: ARIC, Atherosclerosis Risk in Communities; CI, confidence interval; PM, particulate matter; ${\mathrm{PM}}_{10}$, $\mathrm{PM}\le 10\mathrm{\mu }\mathrm{m}$ in diameter; ${\mathrm{PM}}_{2.5}$, $\mathrm{PM}\le 2.5\mathrm{\mu }\mathrm{m}$ in diameter; ${\mathrm{PM}}_{2.5–10}$, $\mathrm{PM}>2.5$ and $<10\mathrm{\mu }\mathrm{m}$ in diameter; WHI, Women’s Health Initiative.

^aModel adjusted for race/ethnicity, age, sex (in ARIC), randomly assigned treatment group (in WHI), mean temperature, mean dew point, mean barometric pressure, season, individual-level education, neighborhood socioeconomic status, smoking status, alcohol use, body mass index and physical activity.

^bHomogeneity of associations among strata was tested using the Cochran’s Q-test statistic, where a $p_{\text{Cochran}’\mathrm{s}Q}<0.10$ suggests there is evidence to reject the null hypothesis of homogeneity.