Mounting evidence supports that fine particulate matter adversely impacts cardio-metabolic diseases particularly in susceptible individuals; however, health effects induced by the extreme concentrations within megacities in Asia is not well described. We enrolled 65 nonsmoking adults with metabolic syndrome and insulin resistance in the Beijing metropolitan area into a panel study of four repeated visits across four seasons since 2012. Daily ambient fine particulate matter (PM2.5) and personal black carbon (BC) levels ranged from 9.0 to 552.5 μg/m3 and 0.2 to 24.5 μg/m3, respectively, with extreme levels observed during January 2013. Cumulative PM2.5 exposure windows across the prior 1-7 days were significantly associated with systolic blood pressure (BP) elevations ranging from 2.0 (95% confidence interval 0.3-3.7) to 2.7 (0.6-4.8) mmHg per standard deviation increase [67.2 μg/m3]), while cumulative BC exposure during the previous 2-5 days were significantly associated with ranges in elevations in diastolic BP from 1.3 (0.0-2.5) to 1.7 (0.3-3.2) mmHg per standard deviation increase [3.6 μg/m3]). Both BC and PM2.5 were significantly associated with worsening insulin resistance (0.18 (0.01-0.36) and 0.22 (0.04-0.39) unit increase per standard deviation increase of personal-level BC, and 0.18 (0.02-0.34) and 0.22 (0.08-0.36) unit increase per standard deviation increase of ambient PM2.5 on lag days 4 and 5). These results provide important global public health warnings that air pollution may pose a risk to cardio-metabolic health even at the extremely high concentrations faced by billions of people in the developing world today.

Background and Purpose: The relationship between stroke and short-term temperature changes remains controversial. Therefore, we conducted a systematic review and meta-analysis to investigate the association between stroke and both high and low temperatures, and health assessment. Methods: We searched PubMed, Embase, Cochrane, China National Knowledge Infrastructure (CNKI) and Wanfang Data up to 14 September 2014. Study selection, quality assessment, and author-contractions were steps before data extraction. We converted all estimates effects into relative risk (RR) per 1 °C increase/decrease in temperature from 75th to 99th or 25th to 1st percentiles, then conducted meta-analyses to combine the ultimate RRs, and assessed health impact among the population. Results: 20 articles were included in the final analysis. The overall analysis showed a positive relationship between 1 °C change and the occurrence of major adverse cerebrovascular events (MACBE), 1.1% (95% confidence intervals (CI), 0.6 to 1.7) and 1.2% (95% CI, 0.8 to 1.6) increase for hot and cold effects separately. The same trends can be found in both effects of mortality and the cold effect for morbidity. Hot temperature acted as a protective factor of hemorrhage stroke (HS), −1.9% (95% CI, −2.8 to −0.9), however, it acted as a risk factor for ischemic stroke (IS), 1.2% (95% CI, 0.7 to 1.8). Conclusion: Short-term changes of both low and high temperature had statistically significant impacts on MACBE.

Exposure to PM2.5 had a statistically significant impact on BP and the magnitude of this effect may have substantially clinical implication.