The coronavirus disease 2019 (COVID-19) pandemic was a major healthcare crisis and exacerbated the issue of childhood overweight and obesity and diabetes mellitus (DM) [
1]. Lockdown restricted all kinds of daily activities with negative changes in eating and sleep behaviors and reductions in physical activity in children and adolescents [
1]. The prevalence of obesity increased in children and adults during the COVID-19 pandemic. According to a recent study by the United States, the rate of body mass index increases nearly doubled compared to the pre-pandemic period among 432,302 persons aged 2–19 years with outpatient visits [
2]. In Korea, the prevalence of obesity has increased among adolescents during the COVID-19 outbreak, in males aged 12–14 years [
3].
In parallel with childhood overweight and obesity, the COVID-19 pandemic might exacerbate the condition of DM. The COVID-19 outbreak has caused new challenges in the management of DM, especially for patients with type 2 DM [
4]. Preliminary studies have shown that in countries that have introduced lockdowns, treatment delays and interruption of treatment, services, and medication supplies in DM patients have occurred. In addition, disease course and glycemic control in DM patients may also be adversely affected by lifestyle changes such as activity restrictions and dietary changes due to COVID-19 lockdowns [
5].
DM is responsible for a significant increase in COVID-19 related mortality, which has been associated with acute respiratory distress syndrome. 6) Thus, good blood glycemic control can strengthen the immune system and reduce the severity of the disease [
7,
8].
A recent study from central India reported that glycemic control worsened in 143 patients with type 2 DM after 3 weeks of lockdown [
9]. These results may be due to psychological stress and difficulties in obtaining medication and medical advice. In Japan (n=1,009) and Korea (n=2,087) as well, it was reported that the COVID-19 pandemic negatively affected blood glycemic control in adult type 2 DM patients [
10,
11]. In addition, a French study has shown that glycemia was less well controlled in patients with gestational DM, likely due to reduced physical activity, modified dietary habits, and anxiety experienced under lockdown [
12]. A systematic review found that lockdown rather determined a short-term worsening in glycemic parameters in patients with type 2 DM [
13].
However, Psoma et al. [
14] reported that blood sugar control improved in Greece during COVID-19 because of several reasons such as a better eating behavior owing to work at home and a chance for more exercise. Önmez et al. [
15] investigated the effects on 101 adult patients with type 2 DM patients of the national lockdown over a 75-day period in Turkey during the global COVID-19 pandemic which showed that statistically insignificant increases were also observed in glycemic parameters. Overall, these findings suggest that the impact of the COVID-19 pandemic on glycemic control differs depending on the type of DM and the region of the world. Unfortunately, all of these studies mentioned above have been conducted on adult type 2 DM, and few studies have been performed on pediatric type 2 DM. Although one study has reported an increase in the number of diagnosed pediatric patients with type2 DM during COVID-19 [
16], evidence on how COVID-19 may affect glycemic control or complications in childhood type 2DM has been very scarce.
Recently, a study on 150 pediatric type 2 DM patients was reported in Korea which shows that glycemic control and complications including hypertension and dyslipidemia of type 2 DM were aggravated during the COVID-19 pandemic, especially in obese children and adolescents [
17]. Considering these results, it may be important to take additional precautions, such as monitoring blood sugar levels regularly and maintaining proper weight, following a healthy diet, regular physical activity, and taking medications as prescribed, in pediatric and adolescent patients with type 2 DM, especially obese patients.
However, this study has limitations, including its small sample size, retrospective study design, and confounding factors that may affect glycemic control and complications in patients with type 2DM. Further analysis of various environmental factors that can affect glycemic control in addition to obesity during COVID-19 and subsequent long-term follow-up studies of these children after the end of COVID-19 may make it clearer to elucidate the COVID-19 related-DM incidence and obesity in pediatric type 2 DM in the future.