Body composition helps to elucidate the different origins of low serum magnesium in children with obesity compared to children with type 1 diabetes

Abstract

Hypomagnesemia in patients with type 1 diabetes (T1D) as well as in obesity has been related to insulin resistance in adults, but not yet in pediatric patients. In this observational single-center study, we aimed to investigate the relation between the magnesium homeostasis, insulin resistance, and body composition in children with T1D and in children with obesity. Children with T1D (n = 148) and children with obesity and proven insulin resistance (n = 121) and healthy controls (n = 36) were included in this study. Serum and urine samples were collected to determine magnesium and creatinine. The total daily dose of insulin (for children with T1D), results from the oral glucose tolerance test (OGTT, for children with obesity), and biometric data were extracted from the electronic patient files. Furthermore, body composition was measured via bioimpedance spectroscopy. Serum magnesium levels were decreased in both children with obesity (0.87 ± 0.07 mmol/l) and children with T1D (0.86 ± 0.07 mmol/l) compared to healthy controls (0.91 ± 0.06; p = 0.005). A lower magnesium level was associated with more severe adiposity in children with obesity, while a worse glycemic control was associated with lower magnesium levels in children with T1D. Conclusion: Children with T1D and children with obesity have decreased serum magnesium levels. An increased fat mass is associated with lower magnesium levels in childhood obesity, indicating that the adipose tissue is an important factor in magnesium homeostasis. In contrast, glycemic control was the main determining factor for serum magnesium levels in children with T1D. What is Known: • Hypomagnesaemia has been related to insulin resistance in both adults with T1D and adults with obesity. • There is an increasing prevalence of obesity and T1D in childhood, but little is known about the relationship between magnesium and insulin resistance in these children. What is New: • Both children with T1D and children with obesity have decreased serum magnesium levels. • In childhood obesity an increased fat mass is associated with lower magnesium levels, while glycaemic control is the main determining factor for serum magnesium in children with T1D.

Keywords: Adolescents; Body composition; Children; Magnesium; Obesity; Type 1 diabetes.