Relationship between ambient fine particles and ventricular repolarization changes and heart rate variability of elderly people with heart disease in Beijing, China.

OBJECTIVE: To explore the effects of particulate matters less than 2.5 µm in aerodynamic diameter (PM2.5) on heart repolarization/depolarization and heart rate variability (HRV). METHODS: We conducted a panel study for elderly subjects with heart disease in Beijing from 2007 to 2008. PM2.5 was measured at a fixed station for 20 h continuously each day while electrocardiogram (ECG) indexes of 42 subjects were also recorded repeatedly. Meteorological data was obtained from the China Meteorological Data Sharing Service System. A mixed linear regression model was used to estimate the associations between PM2.5 and the ECG indexes. The model was adjusted for age, body mass index, sex, day of the week and meteorology. RESULTS: Significant adverse effects of PM2.5 on ECG indexes reflecting HRV were observed statistically and the strongest effect of PM2.5 on HRV was on lag 1 day in our study. However, there were no associations between PM2.5 and ECG indexes reflecting heart repolarization/depolarization. Additionally, the effects of PM2.5 on subjects with hypertension were larger than on the subjects without hypertension. CONCLUSION: This study showed ambient PM2.5 could affect cardiac autonomic function of the elderly people with heart disease, and subjects with hypertension appeared to be more susceptive to the autonomic dysfunction induced by PM2.5.

[Association between ambient PM10/PM2.5 levels and population mortality of circulatory diseases: a case-crossover study in Beijing].

OBJECTIVE: To explore the association between levels of ambient particulate matters (PM10 and PM2.5) and population mortality of circulatory diseases (ICD10: I00~I99) in Beijing. METHODS: The daily data of ambient PM2.5 levels were monitored by the research team in Peking University from Jan. 1, 2007 to Dec. 31, 2008, and the corresponding meteorological and other air quality data (PM10, SO2 and NO2) were collected from National Meteorological Information Center (NMIC) of China and Beijing Environmental Monitoring Center. The data of daily death for the circulatory diseases were collected from the local center for Disease Control and Prevention of Haidian District in Beijing. The symmetric bidirectional case-crossover design and conditional logistic regression model were used for the data analysis. The cases were stratified by gender, age and seasons. The lagged effect was analyzed and the related confounders from meteorological factors and other air pollutants were adjusted. RESULTS: For a 10 µg/m(3) increase of the ambient concentration of PM2.5, the corresponding increase of daily mortality of the circulatory diseases, cardiovascular diseases and cerebrovascular diseases was 0.78% (95% CI: 0.07% to 1.49%), 0.85% (95% CI: -0.28% to 1.99%), and 0.75% (95% CI: -0.17% to 1.68%), respectively, for a 10 µg/m(3) increase of the ambient concentration of PM10, the corresponding increase of daily mortality of the circulatory diseases, cardiovascular diseases and cerebrovascular diseases was 0.36% (95% CI: -0.07% to 0.78%), 0.63% (95% CI: -0.02% to 1.28%), and 0.33% (95% CI: -0.26% to 0.92%),respectively. The significant positive associations were observed statistically between PM2.5 and the circulatory diseases (P<0.05). The association between ambient PMs and the population mortality was stronger in "warm season (April to September)" than in "cool season (October to the next March)" in Beijing (P<0.05). CONCLUSION: The elevated levels of ambient PM2.5 and PM10 were positively associated with the increase of the population mortality of the circulatory diseases, and the association is stronger in warm season, and the adverse effect of PM2.5 is greater than that of PM10.

[Relationship between daily mean temperature and emergency department visits for respiratory diseases: a time-series analysis].

OBJECTIVE: To quantitatively evaluate the influences of daily mean air temperature (DMT) on Emergency Department Visits (EDVs) for the respiratory diseases. METHODS: The EDV data from medical records for respiratory diseases in Peking University Third Hospital between January 2004 and June 2009 were collected. The data of the air pollutants (SO(2), NO(2) and PM(10)) and meteorological factors at the same time periods were also collected from the local authorities of Beijing. Time-series analysis and generalized additive models (GAM) were used to explore the exposurrre-response relationship between DMT and EDVs for respiratory diseases. RESULTS: A total of 35 073 patients [males 14 707(41.93%,14 707/35 073), females 19 122(54.52%,19 122/35 073) and gender missing 1 244(3.55%, 1 244/35 073)] EDVs for respiratory diseases were included. The relationship between DMT and EDVs for the respiratory diseases was mainly of "V" shape, the optimum temperature(OT) was about 4 °C and the effect of DMT was significant with a 0-3 day lag structure for most of the models. When DMT≤OT, each 1°C decrease in DMT corresponded to 3.75% (95% CI of RR: 0.938 3-0.965 3), 3.10% (95% CI of RR:0.949 2-0.989 1), 4.09% (95% CI of RR:0.940 7-0.977 8) increase of EDVs for the overall, male, and female, respectively. When DMT>OT, the value caused by each increase in 1°C in DMT was 1.54% (95% CI of RR:1.006 6-1.024 3), 1.80% (95% CI of RR:1.005 3-1.030 9), and 1.51 (95% CI of RR:1.003 2- 1.027 2), respectively. The effect was statistically significant within the 0-3 day lag. When DMT≤OT, the effect was stronger for the older people, while the effect was strongest for the 45-59 years old people. CONCLUSION: The relationship between DMT and EDVs for respiratory diseases is mainly of "V" type, with an optimum temperature of 4 °C.Both DMT decrease when DMT≤OT and increase when DMT>OT correspond to different increase of EDVs for respiratory diseases. Low DMT has stronger effect than high DMT. Different age group and gender have different effects.