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Background The contribution of long-term ambient PM2.5 exposure to hypertension should not be ignored. However, the conclusions of whether dietary factors play a role in regulating PM2.5-related hypertension are still inconsistent. Objective To explore the correlation between long-term exposure to ambient PM2.5 and blood pressure indicators (systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure) in adults in Ningxia and a potential moderating effect of dietary factors. Methods A set of cross-sectional survey data from March, 2013 to May, 2018 was retrieved from the China Northwest Cohort-Ningxia, and the average ambient PM2.5 concentration in the previous three years was also collected to estimate the long-term exposure of the participants. Binary logistic regression model was used to validate the correlation between long-term exposure to ambient PM2.5 and hypertension in Ningxia, and linear model was used to study the correlation between long-term exposure to ambient PM2.5 and blood pressure indicators (systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure), and to explore the influence of dietary factors on ambient PM2.5-related hypertension. Results A total of 11470 participants were included in the study, 42.2% male and 57.8% female. The three-year average ambient PM2.5 concentration before the baseline survey was 37.0 μg·m−3. Each 1 μg·m−3 increase in ambient PM2.5 was associated with an increased risk of hypertension (OR=1.111, 95%CI: 1.097, 1.125), and increased systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure by 0.886 (95%CI: 0.783, 0.990), 0.570 (95%CI: 0.500, 0.641), 0.676 (95%CI: 0.600, 0.751), and 0.316 (95%CI: 0.243, 0.389) mmHg, respectively. The stratified analysis showed that the OR and 95%CI of hypertension were 1.171 (1.097, 1.254), 1.117 (1.064, 1.174), and 1.160 (1.116, 1.207) respectively for each 1 μg·m−3 increased in PM2.5 with low frequency of vegetable and fruit consumption and salty taste respectively. The OR and 95%CI of hypertension were decreased when the moderate and high frequency of vegetable and fruit intake and moderate and light taste applied, the values were 1.091 (1.062, 1.121) and 1.114 (1.097, 1.131), 1.105 (1.082, 1.129) and 1.111 (1.092, 1.13), 1.115 (1.090, 1.140) and 1.102 (1.083, 1.121) respectively. Compared with low frequency of vegetable and fruit intake and salty taste, the increase degree of ambient PM2.5 related systolic blood pressure, diastolic blood pressure, mean arterial pressure and pulse pressure also decreased in middle and high frequency of vegetable and fruit intake and moderate and light taste. Conclusion Long-term exposure to ambient PM2.5 is significantly associated with increased risks of hypertension and blood pressure in Ningxia area. Increasing the frequency of vegetable and fruit intake and decreasing salty taste may reduce the effect of ambient PM2.5 on hypertension and blood pressure.
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Objective@#To explore the short-term effects of ambient PM2.5 on the outpatient visits of chronic obstructive pulmonary disease (COPD) in Ningbo city.@*Methods@#Through the regional health information platform, number of daily COPD outpatients from the four general hospitals in Ningbo was gathered. Related data on meteorological and air pollution from 2014 to 2016 was also collected. Generalized additive model (GAM) of Possion regression was used to estimate the impact of PM2.5 pollution on COPD outpatients and the lagging effects.@*Results@#In cold (November- April) or warm seasons (May-October), an 10 μg/m3 increase of PM2.5 would result in the excessive number of COPD outpatients as 1.87% (95%CI: 0.98%-2.76%), 2.09% (95%CI: 1.11%-3.08%) and 2.56% (95%CI: 0.56%-4.59%), respectively. In terms of the short-term effects of PM2.5 the strongest was seen in the days of warm season but without delay (P<0.05). The strongest effect appeared at day 4 in cold season and the effect was particularly significant seen in the over 65 year-old group or in the female population. After the introduction of PM10, SO2 and NO2, the concentration of PM2.5, did not show significant effect on the number of hospital visits due to COPD on the same day (P>0.05). The effect of COPD on the fourth day showed a slight change after the lagging, and the effect was statistically significant (P<0.05).@*Conclusion@#The increase of PM2.5 concentration in Ningbo was related to the increase of COPD outpatient numbers. Effective prevention measures should be taken to protect the vulnerable population and to reduce the risk of COPD.