Vitamin D, liver-related biomarkers, and distribution of fat and lean mass in young patients with Fontan circulation

Abstract

Introduction/aim: Young patients with Fontan circulation may have low serum 25-hydroxyvitamin D levels, an affected liver, and unhealthy body compositions. This study aimed to explore the association between vitamin D intake/levels, liver biomarkers, and body composition in young Fontan patients. Method: We collected prospective data in 2017 to 2018, obtained with food-frequency questionnaires, biochemical analyses of liver biomarkers, and dual-energy X-ray absorptiometry scans in 44 children with Fontan circulation. Body compositions were compared to matched controls (n = 38). Linear regression analyses were used to investigate associations of biomarkers, leg pain, and lean mass on serum levels of 25-hydroxyvitamin D. Biomarkers were converted to z scores and differences were evaluated within the Fontan patients. Results: Our Fontan patients had a daily mean vitamin D intake of 9.9 µg and a mean serum 25-hydroxyvitamin D of 56 nmol/L. These factors were not associated with fat or lean mass, leg pain, or biomarkers of liver status. The Fontan patients had significantly less lean mass, but higher fat mass than controls. Male adolescents with Fontan circulation had a greater mean abdominal fat mass than male controls and higher cholesterol levels than females with Fontan circulation. Conclusion: Vitamin D intake and serum levels were not associated with body composition or liver biomarkers in the Fontan group, but the Fontan group had lower lean mass and higher fat mass than controls. The more pronounced abdominal fat mass in male adolescents with Fontan circulation might increase metabolic risks later in life.

Nutritional considerations for people living with a Fontan circulation: a narrative review

“…23,50 Fontan-associated myopenia While reductions in skeletal muscle (also known as fat-free mass) are prevalent in those with complex CHD, limited data have suggested that the deficiencies are more pronounced in the setting of a Fontan circulation, particularly in the lower half of the body. 8,9,39,[51][52][53] A study by Powell and colleagues observed a 14% increase in adiposity and a 15% decrease in lean muscle mass in adolescents with a Fontan circulation when compared to those with complex CHD. 20 In the setting of Fontan physiology, this is especially concerning because the skeletal muscle in the lower limbs acts as a peripheral muscle pump contributing to venous return and cardiac filling.…”

“…48 Concerningly, adiposity tends to accumulate in the trunk or abdominal area. 9,53,70 Given this distribution tendency, there may be merit in measuring waist circumference across all ages to aid in monitoring for excess adiposity although this measurement will be confounded in the presence of ascites. 23,50,[70][71][72] Ascites is likely to develop in 17% of those with a Fontan circulation as a subsequent complication of Fontan-associated liver disease.…”

“…Children with a Fontan circulation may have growth and age-related development concerns (i.e., pubertal delays), both of which are known to potentially impact body composition. 20,48,50,53,69,70,89 Over the last decade, the growth deficits experienced by children with a Fontan circulation compared to their peers have been increasingly well characterised. 69,77,[90][91][92][93][94][95] Terms frequently interchangeably utilised to describe growth deficits include growth failure, malnutrition, poor growth, faltering growth, and undernutrition.…”

“…It is unclear whether increased abdominal adiposity in the setting of Fontan physiology increases the risk of metabolic syndrome, as established in the general population. 53 Metabolic abnormalities of impaired glucose tolerance, insulin resistance, and diabetes mellitus are increasingly recognised as comorbidities associated with Fontan physiology. 13,15,16 Although the pathophysiologic mechanisms explaining abnormalities in glucose metabolism are not fully understood, it has been postulated that it may be related to Fontan-associated liver disease or altered body composition and exacerbated by physical inactivity.…”

“…The prevalence of vitamin D deficiency (<50 nmol/L) among children with a Fontan circulation is estimated to be 20-25%. 53,96,97,119,122 Dietary data on vitamin D intake and levels in adults are lacking. One small cohort study in Australian adults (>16 years) with a Fontan circulation reported an average serum vitamin level of 66 nmol, with 24% of the cohort classified as deficient (<50 nmol/L).…”