Low Levels of Serum Total Vitamin B12 Are Associated with Worse Metabolic Phenotype in a Large Population of Children, Adolescents and Young Adults, from Underweight to Severe Obesity.

Vitamin B12 (or cobalamin) is an essential vitamin for DNA synthesis, fatty acid and protein metabolism as well as other metabolic pathways fundamental to the integrity of cells and tissues in humans. It is derived from the diet and mostly stored in the liver. Its deficiency has been associated with metabolic derangements, i.e., obesity, glucose intolerance, increased lipogenesis and metabolic dysfunction-associated steatotic liver disease (MASLD) and steatohepatitis (MASH). However, data with regard to body weight across the whole spectrum (from underweight to severe obesity) in children and young individuals are scarce. The present study aims to describe the association between serum total vitamin B12 and body mass index (BMI) ranging from underweight to severe obesity in a large population of children, adolescents and young adults. This study also investigates associations with visceral adiposity, glucose and lipid metabolism and liver dysfunction. A cross-sectional, single-centre study was conducted at the Paediatrics and Endocrinology units of the "Bambino Gesù Children Hospital", a tertiary referral institution for eating disorders. Clinical charts were reviewed and 601 patients aged from 5 to 25 years were enrolled in order to analyse anthropometric, auxological, clinical, biochemical and liver ultrasound data using robust statistical approaches. Analyses were adjusted for potential confounders. A reduction in serum total B12 levels was associated with a linear increase in body weight, as expressed by WHO BMI SDS (r = -0.31, p < 0.001, BCa 95% -0.38, -0.24). Lower B12 levels were associated with higher waist circumference but only in pubertal girls (r = -0.33, p = 0.008, BCa 95% -0.53, -0.11). Hepatic insulin resistance was higher in males with lower B12 levels (B = -0.003 (-0.007, -0.0001), p = 0.039), but not in females, whereas whole-body insulin resistance was unaffected. Serum lipid profiles (total, HDL and LDL cholesterol and triglycerides) were not influenced by serum cobalamin levels. However, lower cobalamin levels were associated with higher grading of ultrasound-scored hepatic steatosis (ptrend = 0.035). Lastly, both AST and ALT showed a significant and direct correlation with total B12 levels in underweight (r = 0.22 and 0.24, p = 0.002 and <0.001, respectively) and severely obese subjects (r = 0.24 and 0.32, p = 0.002 and <0.001). In conclusion lower vitamin B12 levels are associated with higher body weight, adiposity and with worse metabolic health in a large population of children, adolescents and young adults.

Childhood Obesity and COVID-19 Lockdown: Remarks on Eating Habits of Patients Enrolled in a Food-Education Program.

Childhood obesity is a worldwide health emergency. In many cases, it is directly linked to inappropriate eating habits and a sedentary lifestyle. During lockdown aimed at containing the coronavirus disease (COVID-19) spread, children have been forced to stay at home. The present study aimed at investigating the lifestyles of outpatients (aged 5-17 years) with complicated obesity enrolled in the day-hospital food education program at the Children's Hospital Bambino Gesù in Rome. A survey was performed based on a structured questionnaire, investigating dietary habits and lifestyles. The questionnaire answers were rated as "yes/no/sometimes" or "often/never/sometimes". Eighty-eight families correctly completed the questionnaire between March and May 2020. The results highlighted that 85.2% (N = 75) of the patients ate breakfast regularly, and 64.3% (N = 72) consumed fruit as an afternoon snack. However, 21.6% (N = 19) did just "often" home workouts, and 50.0% (N = 44) reported an increase of feeling hungry with "sometimes" frequency. There is a significant relationship of feeling hungry with gender (p < 0.0001) and age (p = 0.048) and, also, between gender with having breakfast (p = 0.020) and cooking (p = 0.006). Living a healthy lifestyle during lockdown was difficult for the outpatients, mainly due to the increase in a sedentary lifestyle and the increase in feeling hungry, but some healthy eating habits were maintained, as advised during the food education program provided before lockdown.