Brachial Artery Responses to Ambient Pollution, Temperature, and Humidity in People with Type 2 Diabetes: A Repeated-Measures Study

Abstract

Background: Extreme weather and air pollution are associated with increased cardiovascular risk in people with diabetes.Objectives: In a population with diabetes, we conducted a novel assessment of vascular brachial artery responses both to ambient pollution and to weather (temperature and water vapor pressure, a measure of humidity).Methods: Sixty-four 49- to 85-year-old Boston residents with type 2 diabetes completed up to five study visits (279 repeated measures). Brachial artery diameter (BAD) was measured by ultrasound before and after brachial artery occlusion [i.e., flow-mediated dilation (FMD)] and before and after nitroglycerin-mediated dilation (NMD). Ambient concentrations of fine particulate mass (PM2.5), black carbon (BC), organic carbon (OC), elemental carbon, particle number, and sulfate were measured at our monitoring site; ambient concentrations of carbon monoxide, nitrogen dioxide, and ozone were obtained from state monitors. Particle exposure in the home and during each trip to the clinic (home/trip exposure) was measured continuously and as a 5-day integrated sample. We used linear models with fixed effects for participants, adjusting for date, season, temperature, and water vapor pressure on the day of each visit, to estimate associations between our outcomes and interquartile range increases in exposure.Results: Baseline BAD was negatively associated with particle pollution, including home/trip–integrated BC (–0.02 mm; 95% CI: –0.04, –0.003, for a 0.28 μg/m3 increase in BC), OC (–0.08 mm; 95% CI: –0.14, –0.03, for a 1.61 μg/m3 increase) as well as PM2.5, 5-day average ambient PM2.5, and BC. BAD was positively associated with ambient temperature and water vapor pressure. However, exposures were not consistently associated with FMD or NMD.Conclusion: Brachial artery diameter, a predictor of cardiovascular risk, decreased in association with particle pollution and increased in association with ambient temperature in our study population of adults with type 2 diabetes.Citation: Zanobetti A, Luttmann-Gibson H, Horton ES, Cohen A, Coull BA, Hoffmann B, Schwartz JD, Mittleman MA, Li Y, Stone PH, de Souza C, Lamparello B, Koutrakis P, Gold DR. 2014. Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study. Environ Health Perspect 122:242–248; http://dx.doi.org/10.1289/ehp.1206136

The impact of decreases in air temperature and increases in ozone on markers of endothelial function in individuals having type-2 diabetes

“…The mean temperature (11.2 1C (SD 6.6)) during the study period was lower compared to our study (Nawrot et al, 2005). Zanobetti et al 2014 reported a linear relationship of temperature and brachial artery diameter, but observed no association between temperature and FMD or NTGMD (Zanobetti et al, 2014). However, all the results show that even if people are exposed to temperature changes for a short period of time, since people generally spent most of their time indoors; their body reacts to that environmental stimuli.…”

“…Several studies have reported an association between air pollution and endothelial dysfunction (Briet et al, 2007;Brook, 2002;Hashemi et al, 2012;O'Neill et al, 2005;Schneider et al, 2008). However, only a few studies have examined the impact of air temperature on endothelial function (Nawrot et al, 2005;Widlansky et al, 2007;Zanobetti et al, 2014), and little is known about the interaction between air temperature and air pollution (Burkart et al, 2013;Roberts, 2004;Stafoggia et al, 2008). Flow-mediated dilatation (FMD) of the brachial artery -quantified as the percent change in diameter induced by reactive hyperemia -is a marker of endothelial function.…”

Pretreatment with Antioxidants Augments the Acute Arterial Vasoconstriction Caused by Diesel Exhaust Inhalation

“…Assessed as an overall effect, this change in brachial artery caliber is similar to that observed in a previous study by our group (7), which found an average 0.11-mm decrease in BAd 30 minutes after exposure to DE at 200 mg/m 3 . This finding adds to the growing body of literature confirming that acute exposure to traffic-related air pollutants has a consistent and measurable effect on vasocontractility (7,(14)(15)(16)(17)(18) associated with a simultaneous rise in systemic blood pressure (9,19). Interestingly, in this study, we found evidence that both genetic variations and AO supplementation may alter individual susceptibility to the DE exposure.…”

The effect of ambient temperature on diabetes mortality in China: A multi-city time series study

“…Exposure to hot weather may induce changes in apparent glucose tolerance (Akanji and Oputa, 1991;Moses et al, 1997), which was most likely due to redistribution of blood flow between visceral beds and the cutaneous (Forst et al, 2006;Zanobetti et al, 2014), and increases in insulin absorption (Koivisto et al, 1981). However, the biological mechanism of cold effects on diabetes mortality remains unclear.…”