Opposing effects of particle pollution, ozone, and ambient temperature on arterial blood pressure.
BACKGROUND
Diabetes increases the risk of hypertension and orthostatic hypotension and raises the risk of cardiovascular death during heat waves and high pollution episodes.


OBJECTIVE
We examined whether short-term exposures to air pollution (fine particles, ozone) and heat resulted in perturbation of arterial blood pressure (BP) in persons with type 2 diabetes mellitus (T2DM).


METHODS
We conducted a panel study in 70 subjects with T2DM, measuring BP by automated oscillometric sphygmomanometer and pulse wave analysis every 2 weeks on up to five occasions (355 repeated measures). Hourly central site measurements of fine particles, ozone, and meteorology were conducted. We applied linear mixed models with random participant intercepts to investigate the association of fine particles, ozone, and ambient temperature with systolic, diastolic, and mean arterial BP in a multipollutant model, controlling for season, meteorological variables, and subject characteristics.


RESULTS
An interquartile increase in ambient fine particle mass [particulate matter (PM) with an aerodynamic diameter of ≤ 2.5 μm (PM2.5)] and in the traffic component black carbon in the previous 5 days (3.54 and 0.25 μg/m3, respectively) predicted increases of 1.4 mmHg [95% confidence interval (CI): 0.0, 2.9 mmHg] and 2.2 mmHg (95% CI: 0.4, 4.0 mmHg) in systolic BP (SBP) at the population geometric mean, respectively. In contrast, an interquartile increase in the 5-day mean of ozone (13.3 ppb) was associated with a 5.2 mmHg (95% CI: -8.6, -1.8 mmHg) decrease in SBP. Higher temperatures were associated with a marginal decrease in BP.


CONCLUSIONS
In subjects with T2DM, PM was associated with increased BP, and ozone was associated with decreased BP. These effects may be clinically important in patients with already compromised autoregulatory function.
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. b.hoffmann@uni-duesseldorf.de
Barbara
B
Hoffmann
Heike
H
Luttmann-Gibson
Allison
A
Cohen
Antonella
A
Zanobetti
Celine
C
de Souza
Christopher
C
Foley
Helen H
HH
Suh
Brent A
BA
Coull
Joel
J
Schwartz
Murray
M
Mittleman
Peter
P
Stone
Edward
E
Horton
Diane R
DR
Gold
D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000633:toxicity*; D001794:Blood Pressure / Q000187:drug effects*; D001900:Boston / Q000453:epidemiology; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D005947:Glucose / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D006973:Hypertension / Q000139:chemically induced* / Q000453:epidemiology; D007022:Hypotension / Q000139:chemically induced* / Q000453:epidemiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010083:Oxidants, Photochemical / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity*; D012621:Seasons; D013696:Temperature
D000393:Air Pollutants; D010083:Oxidants, Photochemical; D052638:Particulate Matter; D010126:Ozone; D005947:Glucose