Environmental effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes mellitus.

Ahmed Al‐Qaissi,Eric S Kilpatrick,Andrew T Garrett,Alan S Rigby,Zeeshan Javed,Tim Heise,Stephen L Atkin,Thozhukat Sathyapalan,David Hepburn,Maria Papageorgiou

doi:10.1111/dom.13555

Abstract

This study aimed to explore the effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes. A three-way, cross-over, randomised study was performed in adults with type 1 diabetes mellitus (n = 10). The pharmacodynamics profile of a single dose of short-acting insulin (insulin lispro) was investigated, using a controlled environmental chamber, under three environmental conditions: (a) temperature: 15°C and humidity: 10%; (b) temperature: 30°C and humidity: 10%; and (c) temperature: 30°C and humidity: 60%. A euglycaemic glucose clamp technique ensured constant blood glucose of 100 mg/dL (5.5 mmol/L). The following pharmacodynamic endpoints were calculated: maximum glucose infusion rate (GIRmax ), time to GIRmax (tGIRmax ), total area under the curve (AUC) for GIR from 0-6 hours (AUCGIR.0-6h ), and partial AUCs (AUCGIR.0-1h , AUCGIR.0-2h and AUCGIR.2-6h ). Higher temperature (30°C) under 10% fixed humidity conditions resulted in greater GIRmax (P = 0.04) and a later tGIR.max (P = 0.049) compared to lower temperature (15°C). Humidity did not affect any pharmacodynamic parameter. When the combined effects of temperature and humidity were explored, tGIR.max (P = 0.008) occurred earlier, with a lower late insulin pharmacodynamic effect (AUCGIR.2-6h ; P = 0.017) at a temperature of 15°C and humidity of 10% compared to a temperature of 30°C and humidity of 60%. High ambient temperature resulted in a greater insulin peak effect compared to low ambient temperature, with the contribution of high relative humidity apparent only at high ambient temperature. This suggests that patients with type 1 diabetes mellitus who are entering higher environmental temperatures, with or without high humidity, could experience more hypoglycaemic events.

Highlights

Type 1 diabetes mellitus is characterised by β-cell destruction and a lifelong requirement of exogenous insulin.Insulin requirements depend on insulin absorption from the injection site, the individual’s insulin sensitivity, body composition, inflammatory processes and environmental factors [1, 2]
AUCGIR.0-1h, AUCGIR.0-2h and AUCGIR.0-6h did not differ significantly between the conditions with different temperatures, there was a trend towards a higher AUCGIR 2-6h, when comparing temperature 30oC vs. temperature 15oC (p=0.08) (Table 2)
There was no effect of humidity on insulin pharmacodynamics, as indicated by no significant differences in GIRmax, tGIR.max and area under the curve (AUC) for the time-action profile between the condition at temperature 30oC and humidity

Summary

Results

At temperature 30oC and humidity 10% the time-action curve of insulin was shifted to the right, with a later tGIR.max (p=0.049) and a significantly greater GIRmax (p=0.04), compared to the condition at 15oC temperature and same level of humidity (10%). There was no effect of humidity on insulin pharmacodynamics, as indicated by no significant differences in GIRmax, tGIR.max and AUCs for the time-action profile between the condition at temperature 30oC and humidity. When exploring the combined effects of temperature and humidity, tGIR.max (SF=0.1). 30oC and humidity 60% (Figure 1, Table 2) with less glucose that needed to be infused at lower temperature and humidity, but no differences were seen for early (AUCGIR.0-1h, p=0.48, AUCGIR.0-2h, p=0.87) and overall (AUCGIR.0-6h, p=0.48) effects on insulin action (Table 2)

Conclusions

Introduction

Discussion