The impact of daily mean air temperature on the proportion of time in hypoglycemia in 2,582 children and adolescents with type 1 diabetes - Is this association clinically relevant?

Objectives: To study the potential association between increases in daily mean air temperature and time below range (TBR <54 mg/dl) and time above range (TAR >250 mg/dl) in children and adolescents with type 1 diabetes.

Research Design And Methods: Individuals with type 1 diabetes <21 years with information on daily glucose profiles from the diabetes prospective follow-up study (DPV) were included (n = 2582). Further inclusion criteria were age at least 6 months at diabetes onset, diabetes duration for at least one year and treatment years 2020-2021. Mean daily air temperature and other meteorological parameters from 78 measurement stations in Germany were linked to the individual glucose sensor profile via the five-digit postcode areas of residency. We used multivariable repeated measures fractional logistic regression models with a compound symmetry covariance structure to study the association between a 1 °C increase in daily mean temperature and time in specific glucose ranges.

Results: A 1 °C increase in daily mean temperature was associated with an acute (Odds Ratio (OR) 1.009 (95%-CI 1.007, 1.011)) and up to 7 days delayed (OR 1.003 (1.001, 1.005)) increase in TBR <54 mg/dl. Moreover, an acute decrease in TAR >250 mg/dl (OR 0.997 (0.996, 0.997)) was found.

Conclusions: Results of the DPV registry showed small, but statistically significant changes in TBR and TAR in association with a short-term temperature increase. Higher blood flow and faster insulin absorption might be one possible mechanism. In times of increasing temperature fluctuations meteorological impacts on time in range could become even more relevant.