The Short‐Term Effects and Burden of Ambient Air Pollution on Hospitalization for Type 2 Diabetes: Time‐Stratified Case‐Crossover Evidence From Sichuan, China

Abstract

Type 2 diabetes mellitus (T2DM), a complicated metabolic disease, might be developed or exacerbated by air pollution, resulting in economic and health burden to patients. So far, limited studies have estimated associations between short‐term exposure to air pollution and disease burden of T2DM in China. Hence, we aimed to estimate the associations and burden of ambient air pollutants (NO2, PM10, PM2.5, SO2, and CO) on hospital admissions (HAs) for T2DM using a time‐stratified case‐crossover design. Data on HAs for T2DM during 2017–2019 were collected from hospital electronic health records in nine cities in Sichuan Province using conditional poisson regression. Totally, 92,381 T2DM hospitalizations were recorded. There were significant short‐term effects of NO2, PM10, PM2.5, SO2 and CO on HAs for T2DM. A 10 μg/m3 increment of NO2, PM10, PM2.5, SO2 and CO as linked with a 3.39% (95% CI: 2.26%, 4.54%), 0.33% (95% CI: 0.04%, 0.62%), 0.76% (95% CI: 0.35%, 1.16%), 12.68% (95% CI: 8.14%, 17.42%) and 79.00% (95% CI: 39.81%, 129.18%) increase in HAs for T2DM at lag 6. Stratified analyses modified by age, sex, and season showed old (≥65 years) and female patients linked with higher impacts. Using WHO's air quality guidelines of NO2, PM10, PM2.5, and CO as the reference, the attributable number of T2DM HAs exceeding these pollutants exposures were 786, 323, 793, and 2,127 during 2017–2019. Besides, the total medical costs of 25.83, 10.54, 30.74, and 67.78 million China Yuan were attributed to NO2, PM10, PM2.5, and CO. In conclusion, short‐term exposures to air pollutants were associated with higher risks of HAs for T2DM.

Association between short-term ambient air pollutants and type 2 diabetes outpatient visits: a time series study in Lanzhou, China

“…Therefore we chose these six conventional air monitoring pollutants as exposure variables. 16,18,21,22…”

“…Although extensive evidence has investigated the associations between ambient air pollution and T2DM-related outcomes, 16–22 there are still some gaps in our understanding. First, the majority of prior studies have assessed the correlations between long-term air pollution exposure and the prevalence and incidence of T2DM.…”

“…First, the majority of prior studies have assessed the correlations between long-term air pollution exposure and the prevalence and incidence of T2DM. 23,24 Few investigations have been performed on the relationship between short-term exposures and T2DM morbidity risk, 16–18,22 although short-term exposure to air pollution has been demonstrated to potentially lead to metabolic disruption. 23,24 Second, the results regarding the associations between short-term exposure to air pollution and T2DM morbidity risk were inconclusive.…”

“…25 However, a separate research study conducted in Chengdu did not discover such associations. 26 Third, the data in prior studies have largely focused on hospitalization, 16,18,22 and few researchers have paid attention to daily outpatient visits. Compared to hospitalization, it is more advantageous to use daily outpatient visits than hospitalizations when studying the effects of short-term exposure to pollutants on diseases because hospitalization numbers always tend to be saturated.…”

“…17 Fourth, the majority of prior research conducted in China has focused on specific geographic regions, such as Shijiazhuang, China and Sichuan, China. 16,22 To date, there has been a scarcity of research conducted in cities in the inland northwest, such as Lanzhou, which have experienced a significant worsening of T2DM in recent decades due to more severe air pollution than eastern/southwest Chinese cities. For example, Lanzhou is one of China's ten most polluted cities.…”