ABSTRACT
Background Long-term exposure to ambient fine particulate matter (PM2.5) may increase the risk of diabetes, and a healthy diet can effectively control fasting blood glucose levels. However, it is unclear whether dietary factors have a moderating effect on the risk of diabetes associated with atmospheric PM2.5 exposure. Objective To investigate the association between long-term exposure to PM2.5 and diabetes in rural areas of Ningxia, and potential interaction of long-term exposure to atmospheric PM2.5 and diet on diabetes. Methods The study subjects were selected from the baseline survey data of the China Northwest Cohort-Ningxia (CNC-NX) , a natural population cohort. A total of 13917 subjects were included, excluding participants with missing covariate information. We utilized the annual average ambient PM2.5 concentration from 2014 to 2018 as the long-term exposure level. Logistic regression and multiple linear regression were employed to analyze the associations of long-term atmospheric PM2.5 exposure with diabetes and fasting blood glucose levels. Stratification by frequency of vegetable consumption, frequency of fruit consumption, and salty taste was used to examine moderating effects on the diabetes risk associated with atmospheric PM2.5 exposure. Results The mean age of the 13917 subjects was (56.8±10.0) years, and the prevalence of diabetes was 9.8%. Between 2014 and 2018, the average annual concentration of PM2.5 was (38.10±4.67) μg·m−3. The risk (OR) of diabetes was 1.018 (95%CI: 1.005, 1.032) and the fasting blood glucose was increased by 0.011 (95%CI: 0.004, 0.017) mmol·L−1 for each 1 μg·m−3 increase in PM2.5 concentration. Compared to those who consumed vegetables < 1 time per week, individuals who consume vegetables 1-3 times per week and ≥4 times per week had a reduced risk of developing diabetes by 27.1% (OR=0.729, 95%CI: 0.594, 0.893) and 16.8% (OR=0.832, 95%CI: 0.715, 0.971) respectively. Similarly, when compared to those who consumed fruits <1 time per week, individuals who consumed fruits 1-3 times per week and ≥4 times per week exhibited a reduced risk of diabetes by 16.4% (OR=0.836, 95%CI: 0.702, 0.998) and 18.2% (OR=0.818, 95%CI: 0.700, 0.959) respectively. Fasting blood glucose decreased by 0.202 (95%CI: -0.304, -0.101) mmol·L−1 in participants who ate vegetables 1-3 times per week. The effect of salty taste on diabetes and fasting blood glucose was not significant. The results of stratified analysis by dietary factors and PM2.5 concentration showed that the risks of diabetes were increased in the low PM2.5 pollution-low vegetable intake frequency group and the high PM2.5 pollution-low vegetable intake frequency group compared with the low PM2.5 pollution-high vegetable intake frequency group, with OR values of 3.987 (95%CI: 2.943, 5.371) and 1.433 (95%CI: 1.143, 1.796) respectively. The risk of diabetes was 50.1% higher in participants with high PM2.5 pollution and low fruit intake frequency than in participants with low PM2.5 pollution and high fruit intake frequency (OR=1.501, 95%CI: 1.171, 1.926). No interaction was found between salty taste and PM2.5 on diabetes. Conclusion Long-term exposure to ambient PM2.5 is associated with an increased fasting blood glucose and an elevated risk of diabetes in rural Ningxia population. Increasing the frequency of weekly consumption of vegetables or fruits may have a certain protective effect against diabetes occurrence, as well as a moderating effect on diabetes and fasting blood glucose levels associated with long-term exposure to atmospheric PM2.5.
ABSTRACT
Background The impact of atmospheric fine particulate matter (PM2.5) and ozone (O3) on the mortality of circulatory system diseases cannot be ignored. However, whether the interaction between PM2.5 and O3 can affect population health is rarely reported and requires study. Objective To investigate the individual and interactive impacts of atmospheric PM2.5 and O3 on the mortality of circulatory system diseases in the population of Ningxia region. Methods The data of 119647 deaths due to circulatory system diseases, daily average concentrations of atmospheric pollutants, and meteorological data in Ningxia from 2013 to 2020 were retrieved. PM2.5 was divided into low, medium, and high concentrations according to the primary and secondary national limits (35 and 75 μg·m−3) of the Ambient air quality standards. Similarly, O3 was divided into low, medium, and high concentrations according to the national limits (100 and 160 μg·m−3). Using a generalized additive mixed model based on quasi Poisson distribution, the impacts of atmospheric PM2.5 and O3 as well as their interaction on the mortality of circulatory system diseases were analyzed using the population data of Ningxia region. Results During the target period, males and the ≥ 65 year group accounted for larger proportions of deaths due to circulatory system diseases (55.47% and 79.87% respectively). The daily average concentration of PM2.5 (40.25 μg·m−3) exceeded the national primary limit. In the single pollution model, the highest cumulative lag effects for mortality from circulatory system diseases were PM2.5 exposure over previous 1 d (lag01) and O3 exposure for previous 2 d (lag02), and their excess risk (ER) values were 1.03% (95%CI: 0.67%, 1.40%) and 1.02% (95%CI: 0.57%, 1.50%), respectively. The results of concentration stratification analysis showed that the most significant risks of death from circulatory system diseases [ER (95%CI): 1.12% (0.32%, 1.92%) and 0.95% (0.13%, 1.79%) respectively] were found at medium PM2.5 and O3 concentrations. The interaction analysis revealed that under, a synergistic effect on the risk of death from circulatory system diseases was identified (relative excess risk due to interaction=3.08%, attributable proportion of interaction=2.90%, synergy index=1.89) when considering the coexistence of PM2.5 and O3 above the primary limit. As the concentrations of PM2.5 and O3 increased, the synergistic effect increased the risk of death from circulatory system diseases in the general population, men, women, and the ≥ 65 years group. Conclusion Both atmospheric PM2.5 and O3 can increase the risk of death from circulatory system diseases, and the two pollutants have a synergistic effect on the risk of death from circulatory system diseases.