Table 3.

Estimated effects of a $3\text{-ppb}$ increase in ozone (${\mathrm{O}}_3$) exposure on ${\text{IMT}}_{\text{CCA}}$ progression and CP formation over 10 y, according to baseline participant characteristics.

	$n$	Change of ${\text{IMT}}_{\text{CCA}}$ ($\mathrm{\mu }\mathrm{m}/10\mathrm{y}$)		Odds ratio of CP formation
		95% CI	Interaction p-valuea	95% CI	Interaction p-valuea
Sex	—	—	0.99	—	0.69
Female	1,800	5.6 (0.3, 11.0)	—	1.3 (1.1, 1.5)	—
Male	1,592	5.6 ($-0.3$, 11.5)	—	1.2 (1.0, 1.4)	—
Race	—	—	0.99	—	0.09
White	1,334	5.9 (0.8, 11.0)	—	1.4 (1.2, 1.6)	—
Nonwhite	2,058	5.9 ($-0.7$, 12.4)	—	1.1 (0.9, 1.3)	—
Age at baseline	—	—	0.25	—	0.58
$<60\mathrm{y}$	1,658	3.5 ($-2.1$, 9.0)	—	1.3 (1.1, 1.5)	—
$\ge 60\mathrm{y}$	1,734	7.8 (2.2, 13.4)	—	1.4 (1.2, 1.6)	—
Smoking	—	—	0.36	—	0.09
Never	1,658	3.9 ($-1.7$, 9.5)	—	1.4 (1.2, 1.6)	—
Former and current	1,729	7.4 (1.6, 13.1)	—	1.1 (1.0, 1.3)	—
Diabetes	—	—	0.05	—	0.11
No	3,067	6.5 (2.1, 10.8)	—	1.2 (1.1, 1.3)	—
Yes	325	$-4.5$ ($-21.8$, 12.8)	—	1.6 (1.2, 2.3)	—
Hypertension	—	—	0.91	—	0.30
No	1,996	5.4 (0.1, 10.7)	—	1.1 (1.0, 1.3)	—
Yes	1,396	5.9 (0.0, 11.7)	—	1.4 (1.2, 1.6)	—
Statin use	—	—	0.87	—	0.19
No	2,880	5.9 (0.3, 11.4)	—	1.2 (1.1, 1.4)	—
Yes	511	5.3 (0.0, 10.6)	—	1.3 (1.1, 1.5)	—
Presence of carotid plaqueb	—	—	0.04	—	0.79
No	1,792	7.9 (2.1, 13.7)	—	1.2 (1.1, 1.4)	—
Yes	1,600	0.5 ($-5.4$, 6.3)	—	1.3 (1.1, 1.5)	—

Models included age, sex, race/ethnicity, study region, body mass index, smoking status, pack-years, secondhand smoke exposure, alcohol consumption, physical activity, employment status, high-density lipoprotein cholesterol, total cholesterol, statin use, neighborhood socioeconomic status (SES) index, income, education, systolic and diastolic blood pressure, hypertension, antihypertensive medication, and diabetes. Interquartile range (IQR) for within-city ${\mathrm{O}}_3\text{\hspace{0.17em} exposure}=3\text{\hspace{0.17em} ppb}$. Note: —, no data; CI, confidence interval; CP, carotid plaque; ${\text{IMT}}_{\text{CCA}}$, intima-media thickness of common carotid artery.

^ap-Value by the F test of the three-way interaction between ${\mathrm{O}}_3$, study time, and stratification variable.

^bPresence of carotid plaque at baseline. Subset with no presence of carotid plaque indicate incidence of carotid plaque during follow-up.