Table 1.
Summary of recent studies between ambient and traffic-related exposures with type 2 diabetes incidence or prevalence
| Reference | Study Design | Location | Sample Size | Pollutants | Main Findings |
|---|---|---|---|---|---|
| Eze et. al. (2017) | Longitudinal | Switzerland | 2,631 | NO2 | An IQR increase in NO2 (15 μg/m3) was not associated with incident diabetes [RR=0.87, 95%CI: 0.62, 1.21]. |
| Honda et. al. (2017) | Cross-sectional | United States | 4,121 | PM2.5, NO2 | An IQR increase in one-year moving average PM2.5 (3.9 μg/m3) was associated with diabetes prevalence [POR= 1.35, 95% CI: 1.19, 1.53]. An IQR increase in NO2 (8.6 ppb) was associated with diabetes prevalence [POR=1.27, 95% CI: 1.10, 1.48]. |
| Jerrett et. al. (2017) | Longitudinal | United States | 43,003 | O3 | An IQR increase in O3 (6.7 ppb) was associated with incident T2D [HR=1.18, 95%CI: 1.04, 1.34]. |
| Mazidi et. al. (2017) | Cross- sectional/ecologic | United States | 3106 counties or equivalents from the continental USA, reflecting a population of ~170 million adults | PM2.5 | Average PM2.5 (μg/m3) explained 8.3% of the residual variation in T2D prevalence in males (P < 0.0001) and 11.5% in females (P < 0.0001) after correcting for obesity, race, poverty, education and temperature, |
| O’Donovan et. al. (2017) | Cross-sectional | United Kingdom | 10,443 | PM2.5, PM10, NO2 | NO2 (μg/m3) was not associated with T2D prevalence after adjustment for demographic factors [OR= 1.08; 95% CI: 0.91, 1.29], further adjustment for lifestyle factors [1.10, 95% CI: 0.92, 1.32], and further adjustment for neighborhood green space [OR=0.91, 95% CI: 0.72, 1.16]. PM2.5 and PM10 were not significantly associated with T2D prevalence (p-value >0.05). |
| Requia et. al. (2017) | Cross- sectional/ecologic | Canada | 117 health regions | PM2.5 | A 2-year increase of 10 μg/m3 in PM2.5 was associated with a 5.43% increase in incidence of diabetes [95%CI: 2.28%, 12.53%]. |
| Sohn et. al. (2017) | Cross-sectional | South Korea | 96,608 | PM10, SO2 | Exposure to PM10 (μg/m3) and SO2 (10−3 ppm) was associated with the prevalence of T2D among women [OR=1.01, 95%CI: 1.003, 1.013; OR=1.032, 95% CI: 1.004, 1.062, respectively], but not among men [OR=1.003, 95% CI: 0.998, 1.008; OR=0.98, 95% CI: 0.952, 1.006]. |
| Strak et. al. (2017) | Cross-sectional | Netherlands | 387,195 | PM10, PM2.5, PM10 - 2.5, NO2, OPDDT, OPESR | All pollutants, except PM2.5, were associated with diabetes prevalence. An IQR increase in NO2 (7.76 μg/m3) and OPDTT (0.28 nmol DTT/min/m3) was associated with diabetes prevalence [OR=1.07, 95%CI:1.05, 1.09; 1.08, 95% CI: 1.05, 1.10, respectively]. |
| Coogan et. al. (2016) | Longitudinal | United States | 43,003 | NO2 | NO2 was not associated with diabetes incidence (p-value >0.05). |
| Dzhambov et. al. (2016) | Cross-sectional | Plovdiv, Bulgaria | 513 | PM2.5, BaP, traffic density | No significant associations with T2D for any pollutants (p-value >0.05). |
| Hansen et. al. (2016) | Longitudinal | Denmark | 24,174 | PM10, PM2.5, NOx, NO2 | An IQR increase in PM2.5 (3.1 μg/m3) increased diabetes incidence [HR=1.11, 95% CI: 1.02, 1.22]. An IQR increase in PM10 (2.8 μg/m3) [HR=1.06, 95% CI: 0.98, 1.14], NO2 (7.5 μg/m3) [HR=1.05, 95%CI: 0.99, 1.12] and NOX (10.2 μg/m3) [HR=1.01, 95% CI: 0.98, 1.05] was weakly associated with diabetes incidence. Associations with PM2.5 enhanced in non-smokers, obese women, and heart disease patients. |
| Lazarevic et. al. (2015) | Cross-sectional | Australia | 26,991 | NO2, distance to major/minor road | No significant associations were found between any pollutant and diabetes prevalence (p-value >0.05). |
| Liu et. al. (2016) | Cross-sectional | China | 11,847 | PM2.5 | An IQR increase in PM2.5 (41.1 μg/m3) was associated with increased T2D prevalence [PR: 1.14, 95% CI: 1.08, 1.20]. |
| Park et. al. (2015) | Longitudinal | 6 US sites* | 5,839 | PM2.5, NOx | An IQR increase in PM2.5 (2.43 μg/m3) and NOx (47.1 pbb) was associated with T2D prevalence [OR=1.09, 95%CI: 1.00, 1.17; OR=1.18, 95% CI: 1.00, 1.38, respectively]. |
| To et. al. (2015) | Cross-sectional | Canada | 29,549 | PM2.5 | A 10 μg/m3 increase in PM2.5 was associated with diabetes [PR=1.28, 95% CI: 1.16, 1.41]. Risks elevated in the obese. |
| Weinmayr et. al. (2015) | Longitudinal | Germany | 3,607 | PM10, PM2.5 | An increase of 1 μg/m3 in PM10 [RR=1.05, 95% CI: 1.00, 1.10) and PM2.5 [RR=1.03, 95% CI: 0.95, 1.12] was associated with incident T2D. Traffic- specific PM10 and PM2.5 were more strongly associated with T2D [RR=1.36, 95%CI: 0.98, 1.89; RR=1.36, 95% CI: 0.97, 1.89, respectively]. Individuals closer than 100m to busy road had a higher risk of incident T2D [RR=1.37, 95% CI: 1.04, 1.81]. |
| Chien et. al. (2014) | Cross- sectional/ecologic | United States | 3109 counties in the 48 contiguous states | PM2.5 | An increase in 1 μg/m3 PM2.5 increased the relative risk percentage for diabetes from −5.47 (95% credible interval: −6.14, −4.77) to 2.34% (95% credible interval: 2.01, 2.70) where 1323 of 3109 counties (42.55%) displayed diabetes vulnerability with significantly positive risk percentages. |
| Eze et. al. (2014) | Cross-sectional | Switzerland | 6,392 | PM10, NO2 | PM10 and NO2 were associated with prevalent diabetes [OR= 1.40, 95% CI: 1.17, 1.67; OR=1.19, 95% CI: 1.03, 1.38, respectively] per 10 μg/m3 increase in average home outdoor level. |
| Chen et. al. (2013) | Longitudinal | Ontario, Canada | 62,012 | PM2.5 | A 10 μg/m3 increase in PM2.5 was associated with incident diabetes 1.11 (95% CI:1.02, 1.21). |
| Andersen et. al. (2012) | Longitudinal | Denmark | 57,053 | NO2, traffic density/proximity | An IQR increase in NO2 (4.9 μg/m3) was associated with confirmed diabetes incidence [HR=1.04, 95% CI:1.00–1.08]. Traffic load within 100 m was associated with confirmed diabetes incidence [HR=1.02, 95%CI: 1.00, 1.04]. NO2 effects were enhanced in nonsmokers, [HR=1.12, 95% CI: 1.05, 1.20] and physically active people [HR=1.10, 95% CI:1.03, 1.16]. |
| Coogan et. al. (2012) | Longitudinal | Los Angeles, California | 3,992 | NOx, PM2.5 | A 10 μg/m3 in PM2.5 and an IQR increase in NOx (12.4 parts ppb) was associated with diabetes [IRR=1.63, 95% CI: 0.78, 3.44; IRR=1.25, 95% CI: 1.07, 1.46, respectively]. |
Summarizes the main findings from studies in adults between 2012 and 2017 that were included in this review. Bap: benzo alpha pyrene, CI: confidence interval, DTT: dithiothreitol, HR: hazard ratio, IQR: interquartile range, IRR: incidence rate ratio, nmol: nanomole, NO2: nitrogen dioxide, NOx: nitrogen oxide, O3: ozone, OPDTT: oxidative potential dithiothreitol OPESR: oxidative potential electron spin resonance, OR: odds ratio, PM: particulate matter, POR: prevalence, ppb: parts per billion, ppm: parts per million, PR: prevalence ratio, RR: risk ratio, SO2: sulfur dioxide, T2D: type 2 diabetes.
*
Six US sites included Baltimore, Maryland; Chicago, Illinois; Forsyth County, North Carolina; Los Angeles County, California; New York, New York; St. Paul, Minnesota