This study investigated the acute effects of the COVID-19 pandemic on the lifestyle of patients with T1D. Based on our findings, patients with T1D reported increased stress levels and decreased exercise volumes during the COVID-19 pandemic. Furthermore, compared with changes in HbA1c for 3 months during pre-pandemic year, changes in HbA1c during the pandemic year were worse in patients with T1D.
Recent studies have revealed that the COVID-19 pandemic is associated with increased stress levels in the general population [7]. External stress may lead to reduced physical activity [17, 18]. Stress can also affect metabolic parameters in patients with diabetes mellitus [19]. In fact, stress and lifestyle changes during the COVID-19 pandemic are associated with worse glycemic control and body weight in patients with type 2 diabetes (T2D) [20]. In addition, previous studies have shown that earthquakes are associated with increased stress and worse glycemic control in patients with T1D [8, 9]. Conversely, there was no association between external stress or reduced physical activity and changes in Hb1c or body weight in this study. This may be due to the small number of participants. Therefore, further large-scale studies are required to clarify this association. The COVID-19 pandemic is ongoing, and there are concerns that impact on patients with diabetes mellitus will continue or worsen. High glucose levels have been reported to be associated with increased mortality during COVID-19 infection [10, 11]. Therefore, attention should be paid to glycemic control in patients with T1D.
In this study, body weight did not change due to the COVID-19 pandemic, which is the same as in previous studies [8, 9]. Contrariwise, there was an association between sleep duration and changes in body weight in patients with T1D. Short sleep duration has been reported to be associated with weight gain [21]. Therefore, it is necessary to pay attention to the deterioration of glycemic control with weight gain among patients with decreased sleep duration, although there was no association between sleep duration and glycemic control.
In this study, changes in glycemic control over 3 months in patients with T1D was worse than that in the previous year. A previous study has revealed that there are no negative effects of a lockdown due to the COVID-19 pandemic on glycemic control in people with T1D [12, 22,23,24,25]. These studies have suggested that the reason why lockdown due to COVID-19 pandemic does not adversely affect glycemic control in patients with T1D might be due to improved lifestyle with continuous glucose monitoring [24, 25]. These studies have also shown that the reason why there are no negative effects of a lockdown due to COVID-19 might be because many patients with T1D do not have to attend work due to lockdown. Thus, there is a possibility that many participants in this study were elderly; not having jobs only had negative aspects, such as reduced exercise volume and increased stress levels.
This study had several limitations. Firstly, the sample size was relatively small; participants were limited to a single center. In addition, this study only included patients who visited our department during the COVID-19 pandemic. Therefore, data of patients who did not visit were not included. There is a possibility that patients who did not visit our department experienced more stress or changes in lifestyle and, therefore, had poor glycemic control. Secondly, the questionnaire in this study was subjective and did not include a quantitative evaluation. However, during the pandemic, reduced contact time is essential to reduce the risk of disease transmission. Therefore, we only asked the patients a minimum number of questions for simplicity. Thirdly, we did not have data on self-monitoring of blood glucose and/or flash glucose monitoring. Fourthly, we did not have data on changes in the dosage of insulin, although patients with T1D are likely to change the dosage of insulin on their own. However, despite the possibility of self-titration, glycemic control worsened, compared to the previous year. Fifthly, examining whether patients with T1D experienced more stress than controls, including healthy adults and patients with type 2 diabetes during the coronavirus pandemic is essential. Unfortunately, however, stress levels and lifestyle factors of healthy adults during the COVID-19 pandemic have not been examined. Conversely, compared with the data of patients with type 2 diabetes in our previous study [21], there were no differences between the questionnaire scores of patients with T1D and those with type 2 diabetes. Lastly, this study only included Japanese patients; therefore, whether our findings can be generalized to populations of other countries remains unclear.