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

Abstract

Objective This study aimed to explore the effects of ambient temperature and relative humidity on insulin pharmacodynamics in adults with type 1 diabetes. Materials and methods 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). Results 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%. Conclusions 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.

Association between Heat Exposure and Hospitalization for Diabetes in Brazil during 2000–2015: A Nationwide Case-Crossover Study

“…2013). High ambient temperatures may also result in a greater insulin peak effect, thereby increasing the risk of a hypoglycemic episode (Al-Qaissi et al. 2019; Dumke et al.…”

Geographical disparities in the impacts of heat on diabetes mortality and the protective role of greenness in Thailand: A nationwide case-crossover analysis

“…However, mechanisms that link exposure to heat and diabetes risk has not been fully elucidated, with some plausible explanations proposed by researchers. Diabetes was reported to cause impairment in eccrine sweating that leads to a marked reduction in the capacity to dissipate heat (Al-Qaissi et al, 2019). During heat exposure, individuals with diabetes have lower skin blood flow and sweating responses, as well as greater insulin absorption and peaking effect, which can have important consequences for cardiovascular regulation and glycemic control (Al-Qaissi et al, 2019;Kenny et al, 2016).…”

“…Diabetes was reported to cause impairment in eccrine sweating that leads to a marked reduction in the capacity to dissipate heat (Al-Qaissi et al, 2019). During heat exposure, individuals with diabetes have lower skin blood flow and sweating responses, as well as greater insulin absorption and peaking effect, which can have important consequences for cardiovascular regulation and glycemic control (Al-Qaissi et al, 2019;Kenny et al, 2016). Furthermore, diabetes is often accompanied by one or more other health conditions such as cardiovascular disease and hypertension.…”

“…One such environmental risk factor that may be culpable is ambient temperature since it is an important determinant of human health (Watts et al, 2018). Heat exposure is considered to adversely affect diabetics in multiple ways, including disturbing normal regulation of the cardiovascular system and glycaemic control (Al-Qaissi et al, 2019;Kenny et al, 2016). Although the adverse effects of heat on mortality have been well documented in previous literature, most of these report on deaths from all-cause, cardiovascular or respiratory diseases (Chen et al, 2018;Gasparrini et al, 2015;Sera 4 et al, 2019).…”

Passive heating and glycaemic control in non-diabetic and diabetic individuals: A systematic review and meta-analysis

“…It is possible, however, with inappropriate PH protocols such an event may occur. For example, PH increases absorption of exogenously delivered insulin which could increase the likelihood of hypoglycaemic events [72,88]. Thermal sensations and thermoregulation may also be impaired in diabetic individuals [87,89] which could lead to burns and heat-related illness.…”