Bone health and nutrition treatment. Studies on young women with anorexia nervosa and children with epilepsy

Abstract: Background: Adequate nutritional status is crucial for optimal longitudinal growth and accrual of bone mass during childhood and adolescence. Peak bone mass achieved in young adulthood affects bone health throughout life. Anorexia nervosa (AN) is associated with impaired bone health, and the cornerstone for treatment is weight restoration through nutrition treatment. For children with refractory epilepsy, the modified Atkins diet (MAD) is a treatment option to reduce the number of seizures. The aim of this thesis was to clarify the effects of these two different nutrition treatments on bone health, body composition, and growth. Methods and results: Two cohorts were studied: young women with AN (papers I–III) and children with therapy-resistant epilepsy (paper IV). In paper I, levels of 25-hydroxy vitamin D (25(OH)D) were evaluated in 25 young women with severe AN during 12 weeks of intensive nutrition treatment; the level was found to be adequate but decreased during treatment despite a high intake. No association was found between 25(OH)D and BMI or bone mass measured with dual-energy X-ray absorptiometry (DXA). In paper II, the role of the fat mass and obesity associated (FTO) gene for weight gain and body composition was evaluated, and no difference between the genotype groups (AA, TA, and TT) was observed. Paper III is a 3-year follow-up of women with AN, where bone health was assessed by DXA, peripheral quantitative computed tomography, and bone biomarkers and compared to healthy young women. BMI and body composition were stable, and there were positive changes in bone biomarkers. Despite this, trabecular density decreased, and most bone mass parameters were lower in AN subjects than in the healthy women. In paper IV, growth, and bone mass measured with DXA and with DXA and laser was evaluated in 38 children with epilepsy treated with MAD for 24 months. Of these, 53% responded well to the diet (seizure reduction >50%) and there were no negative effects on growth or bone mass. Conclusions: A high intake of vitamin D is needed to preserve sufficient vitamin D levels during in-hospital nutrition treatment for AN. Individualized nutrition treatment for AN based on the FTO genotype could not be supported according to our study. AN in adolescence negatively affects bone acquisition, which is why early evaluation of bone health and a structured long-term follow-up is essential in women with AN, even in individuals who have recovered. MAD is effective for seizure reduction and can be considered a safe epilepsy treatment option in children and adolescents in terms of growth and bone health.