Influence of short-term exposure to fine particulate matter and ozone on blood glucose and blood pressure in elderly patients with type 2 diabetes Mellitus in Taiyuan, China

Objective To investigate the influence of fine particulate matter (PM_2.5) and ozone (O₃) on blood glucose and blood pressure in elderly patients with type 2 diabetes mellitus(T2DM) in Taiyuan, China, so as to provide a theoretical basis for the prevention and treatment of T2DM in elderly patients.

Methods A total of 702 elderly patients with T2DM were recruited from six communities in a district of Taiyuan in 2020. A questionnaire survey was performed to collect the information of the subjects such as gender, age, education level, smoking and drinking status, and family history. Mass concentrations of ambiet PM_2.5 and O₃ and meteorological data during the same period were matched according to the subjects' residential addresses. Generalized linear model analysis was used to investigate the associations of the concentration of air pollutants with blood glucose and blood pressure. According to the presence or absence of comorbidities, the elderly patients with T2DM were divided into patients with simple type 2 diabetes(ST2DM) and patients with type 2 diabetes combined with other diseases(T2DMCOD). The influence of the exposure concentration of PM_2.5 and O₃ on blood glucose and blood pressure was analyzed in the total population, the elderly patients with ST2DM, and the elderly patients with T2DMCOD, and in the total population of different subgroups of the elderly patients with T2DM.

Results After adjustment for the confounding factors such as gender, body mass index, and smoking, PM_2.5 exposure concentration on lag1, lag02, and lag03 days was associated with the increased systolic blood pressure (SBP) in the total population and the elderly patients with ST2DM, and for every interquartile range (IQR) increase in PM_2.5 mass concentration, SBP of the total population was increased by 1.08% (0.31%-1.84%), 0.82% (0.04%-1.61%), and 0.87% (0.08%-1.67%) on lag01, lag02, and lag03 days, respectively, while SBP of the elderly patients with ST2DM was increased by 1.26% (0.15%-2.37%), 1.24% (0.06%-2.41%), and 1.31% (0.11%-2.50%), respectively. On lag1 day, pulse pressure (PP) of the total population was increased by 2.18% (0.33%-4.03%) with the increase in PM_2.5 mass concentration. On lag03 day, SBP of the total population was decreased by 1.69% (0.06% to 3.32%) with the increase in O₃ exposure concentration, and on lag01 and lag02 days, PP was decreased by 3.38% (0.12% to 6.64%) and 3.80% (0.16% to 7.42%), respectively. In the elderly patients with ST2DM, diastolic blood pressure(DPB) was decreased by 3.13% (0.46% to 5.81%) with the increase in O₃ exposure concentration on lag2 day. Stratified analysis showed that SBP and PP increased with the increase of PM_2.5 mass concentration in males, overweight individuals, and smokers.

Conclusion The exposure levels of PM_2.5 and O₃ in Taiyuan are associated with the increase and decrease of blood pressure in elderly patients with T2DM, especially in the elderly patients with ST2DM. There are no correlations between PM_2.5 and O₃ exposure levels and fasting blood glucose (FBG) in elderly patients with T2DM. Among the elderly patients with T2DM, males, overweight, and smoking are more susceptible to PM_2.5.