Lower air ozone concentration is associated with clinical remission in type 1 diabetes diagnosed in adulthood: a prospective, observational study in Wielkopolska region, Poland

INTRODUCTION Clinical remission in type 1 diabetes (T1D) results from metabolic compensation after insulin implementation and is caused by various factors.OBJECTIVES Our aim was to investigate an association between air pollution defined based on ozone concentration in the month of T1D diagnosis and the early course of the disease, that is, glucose metabolism and the occurrence of remission.PATIENTS AND METHODS This prospective, observational analysis included 96 adult patients with newly diagnosed T1D. The study group was divided according to the occurrence of remission at 12 months after the diagnosis. The levels of ambient ozone measured within the month of T1D diagnosis were calculated using the official data of Poland's Chief Inspectorate of Environmental Protection. Remission was defined according to the following formula: actual glycated hemoglobin (HbA(1c))(%) level + [4 x insulin dose (units/kg per 24 h)] - value defining partial remission <= 9.RESULTS The remission rate after 12 months was higher in the group where ozone concentration was below or equal to the median for the study population (P <0.001). Moreover, the patients in the group where ozone levels were above the median, presented lower C-peptide levels (P = 0.01), higher HbA(1c) concentration (P = 0.005), and higher daily insulin requirements (P = 0.02) after 12 months from the diagnosis. Also, in the group of participants achieving remission, the ambient ozone level was lower (P <0.001). In a multivariable logistic regression analysis, the increased ozone concentration in the month of diagnosis was the variable that influenced the lack of remission after 12 months, independently of sex and smoking (P <0.001).CONCLUSIONS Increased ozone level may exacerbate metabolic outcomes and reduce remission in T1D.