Obesity and Vitamin D Status in Children Are Linked to Genomic Instability and Cancer
Epidemiological evidence, based on studies of human populations under real-world conditions, shows that obesity in childhood and adolescence is an independent risk factor for cancer and premature death in adulthood.
Researchers at the University of Westminster, London, working in collaboration with doctors at King's College Hospital, London, and St George's Hospital, London, have shown that obese children and adolescents experience higher levels of genomic instability, which potentially increases their risk of cancer in adulthood.
The researchers followed on from previous studies that claimed excess fat tissue can lead to increased inflammation and nutritional deficiencies, including vitamin D.
Obesity has previously been associated with micro-nutritional deficiencies, with obese children often found to be deficient in several micronutrients including iron, selenium, folate, zinc, and vitamins A, D and E. Though it is vitamin D deficiency that is increasingly being diagnosed in children in the UK and a causative association between obesity and vitamin D deficiency has shown that a 10% increase in BMI may reduce levels of vitamin D by 4.2%. Vitamin D is increasingly garnering attention due to its role in inhibiting inflammation, protecting cells from DNA damage, inducing cell-cycle arrest and promoting apoptosis.
Genomic instability is known to lead to an increased rate of DNA mutation in a cell and result in a higher likelihood of cancer development. Thus the scientists analysed a variety of measurements from children and adolescents with and without obesity to develop a new approach for predicting genomic instability.
132 children and adolescents aged 10–18 were involved in the study. Quantitative measurements of body composition, including BMI Z-score, waist and hip circumference, and body fat percentage were taken. In addition, inflammation and vitamin D levels in saliva and DNA damage through urine and cheek swab samples were also assessed to score for genomic instability.
The results from the cross-sectional study that recruited participants from schools and paediatric obesity clinics in London were published in the International Journal of Obesity. The researchers found that obesity, vitamin D levels and oxidative DNA damage are three significant predictors of genomic instability that, taken together, could allow for non-invasive monitoring and predictive modelling of genomic instability in young patients with obesity.
The authors of the paper believe that predictive modelling based on these findings could assist clinicians in interpreting the significance of weight-loss interventions in children and adolescents, and support them with prioritising the provision of further clinical measures to help reduce the risk of cancer later in life.
These findings could help to assess the risk for young individuals with obesity to develop cancer in later life, and help target efforts to reduce the risk of cancer.
Usman M, et al (2021). Obesity, oxidative DNA damage and vitamin D as predictors of genomic instability in children and adolescents. International Journal of Obesity (2021). Available at: https://doi.org/10.1038/s41366-021-00879-2
Basatemur E, et al (2017). Trends in the diagnosis of vitamin D deficiency. Pediatrics (2017) 139 (3) e20162748. Available at: https://doi.org/10.1542/peds.2016-2748
Vimaleswaran KS, et al (2013). Causal relationship between obesity and vitamin D status: bi-directional Mendelian randomization analysis of multiple cohorts. PLoS Med. (2013) 10:e1001383. Available at: https://doi.org/10.1371/journal.pmed.1001383