Overweight modifies the association between long-term ambient air pollution and prehypertension in Chinese adults: the 33 Communities Chinese Health Study

Table 4 Associations of air pollutants with blood pressures and prehypertension in two BMI categories (multiple-pollutant model)

	Normal weight	Overweight	Pollutant*overweight	p _interaction
Pollutant	Estimate (95% CI)^abc	Estimate (95% CI)^abc	Estimate (95% CI)^abd	value
SBP
PM₁₀	0.21 (− 0.30, 0.73)	2.22 (1.57, 2.88)	2.93 (2.48, 3.39)	< 0.0001
SO₂	0.16 (− 0.22, 0.55)	1.68 (1.18, 2.17)	2.48 (2.00, 2.97)	< 0.0001
NO₂	0.20 (−0.27, 0.67)	2.04 (1.44, 2.64)	1.91 (1.34, 2.49)	< 0.0001
O₃	0.21 (−0.29, 0.71)	2.16 (1.52, 2.80)	2.73 (2.17, 3.28)	< 0.0001
DBP
PM₁₀	0.24 (−0.11, 0.59)	1.07 (0.65, 1.49)	0.99 (0.69, 1.30)	< 0.0001
SO₂	0.18 (−0.08, 0.44)	0.80 (0.49, 1.12)	0.83 (0.51, 1.16)	< 0.0001
NO₂	0.22 (−0.10, 0.54)	0.98 (0.59, 1.36)	0.72 (0.34, 1.11)	0.0002
O₃	0.23 (−0.11, 0.57)	1.04 (0.63, 1.45)	0.91 (0.54, 1.28)	< 0.0001
Prehypertension prevalence
PM₁₀	0.99 (0.92, 1.06)	1.18 (1.09, 1.27)	2.40 (1.85, 2.95)	< 0.0001
SO₂	0.99 (0.93, 1.04)	1.14 (1.07, 1.22)	2.12 (1.71, 2.53)	< 0.0001
NO₂	1.02 (0.95, 1.09)	1.12 (1.03, 1.21)	0.51 (0.18, 0.83)	0.0021
O₃	0.99 (0.92, 1.06)	1.18 (1.08, 1.27)	1.53 (1.21, 1.84)	< 0.0001

^aAdjusted by age, sex, race, education, income, smoking, drinking, exercise, diet, sugar intake, family history of hypertension, gross domestic product, population density, and residuals generated from regression analyses for highly correlated pollutants (PM₁₀ vs. SO₂, PM₁₀ vs. NO₂, PM₁₀ vs. O₃, and SO₂ vs. O₃)
^bEstimate was scaled to the interquartile range (IQR) for each pollutant (19 μg/m³ for PM₁₀, 20 μg/m³ for SO₂, 9 μg/m³ for NO₂, and 22 μg/m³ for O₃)
^cEstimate for SBP and DBP was regression coefficient (β), and for prehypertension prevalence were PRR
^dInteractive estimate for SBP and DBP with body mass index categories was regression coefficient (β) and its corresponding 95% CI, and for PRR was the relative excessive risk due to interaction (RERI) and its corresponding 95% CI
Pollutant*overweight indicates the interaction of air pollution with overweight

ISSN: 1476-069X