Tracking of bone mass from childhood to puberty: a 7-year follow-up. The CHAMPS study DK

Relationship Between Muscle Strength, Body Composition and Bone Mineral Density in Adolescents

Adolescence is an important period for the acquisition of bone mass, which can be enhanced by several factors. This study aimed examine the relationships of handgrip strength, free-fat mass, and fat mass with bone mineral density in adolescents. 118 adolescents (60 girls), aged 10 to 14 years, participated in the study. Information on sex, age, handgrip strength, free-fat mass, fat mass and bone mineral density were collected. Multiple linear regression analyses were conducted to examine possible relationships between bone mineral density and handgrip strength, free-fat mass and fat mass. There was a relation between handgrip strength and free-fat mass with bone mineral density in both sexes. Fat mass was correlated with bone mineral density only in girls (r= 0.314, p< 0.014). The final models, adjusted for sexual maturation, included free-fat mass (girls - β= 0.419, p< 0.001; boys - β= 0.455; p< 0.001) and handgrip strength (girls - β= 0.358, p< 0.05; boys - β= 0.325; p< 0.05) and these variables together explained 51.8% and 62.9% of the variation of bone mineral density, in girls and boys, respectively. Handgrip strength and free-fat mass were positively associated with bone mineral density. A sex-specific difference indicated that higher levels of free-fat mass are of paramount importance for both sexes.

Management of primary and secondary osteoporosis in children

Osteoporosis in children differs from adults in terms of definition, diagnosis, monitoring and treatment options. Primary osteoporosis comprises primarily of osteogenesis imperfecta (OI), but there are significant other causes of bone fragility in children that require treatment. Secondary osteoporosis can be a result of muscle disuse, iatrogenic causes, such as steroids, chronic inflammation, delayed or arrested puberty and thalassaemia major. Investigations involve bone biochemistry, dual-energy X-ray absorptiometry scan for bone densitometry and vertebral fracture assessment, radiographic assessment of the spine and, in some cases, quantitative computed tomography (QCT) or peripheral QCT. It is important that bone mineral density (BMD) results are adjusted based on age, gender and height, in order to reflect size corrections in children. Genetics are being used increasingly for the diagnosis and classification of various cases of primary osteoporosis. Bone turnover markers are used less frequently in children, but can be helpful in monitoring treatment and transiliac bone biopsy can assist in the diagnosis of atypical cases of osteoporosis. The management of children with osteoporosis requires a multidisciplinary team of health professionals with expertise in paediatric bone disease. The prevention and treatment of fragility fractures and improvement of the quality of life of patients are important aims of a specialised service. The drugs used most commonly in children are bisphosphonates, that, with timely treatment, can give good results in improving BMD and reshaping vertebral fractures. The data regarding their effect on reducing long bone fractures are equivocal. Denosumab is being used increasingly for various conditions with mixed results. There are more drugs trialled in adults, but these are not yet licenced for children. Increasing awareness of risk factors for paediatric osteoporosis, screening and referral to a specialist team for appropriate management can lead to early detection and treatment of asymptomatic fractures and prevention of further bone damage.

Testosterone Therapy in Adolescent Boys: The Need for a Structured Approach

BACKGROUND

In adolescents, testosterone may have several effects including promotion of secondary sexual characteristics and pubertal growth, attainment of optimal muscle mass and peak bone mass, optimization of the metabolic profile, and psychosocial maturation and well-being.

SUMMARY

Testosterone therapy is a cornerstone of the management of hypogonadism in boys. Since the initial report of the chemical synthesis of testosterone, several formulations have continued to develop, and although many of these have been used in boys, none of them have been studied in detail in this age group. Given the wide ranging effects of testosterone, the level of evidence for their effects in boys and the heterogeneity of conditions that lead to early-onset hypogonadism, a standardized protocol for monitoring testosterone replacement in this age group is needed. Key Messages: In this review, we focus on the perceived benefits of androgen replacement in boys affected by pubertal delay and highlight the need to improve the health monitoring of boys who receive androgen replacement therapy, proposing different approaches based on the underlying pathophysiology.

Bone status of young adults with periodic avoidance of dairy products since childhood

Proper nutrition throughout childhood and adolescence is crucial for normal bone development. We investigated whether adherence to Christian Orthodox Church fasting is characterized by periodic avoidance of animal foods (including dairy products), since childhood affects stature or bone health in young adults. This cross-sectional study included 200 healthy men and women, aged 18-35, of whom 100 had been following religious fasting for a median of 14 years, starting at the age of 10, and 100 were non-fasters. Measurements included body height; bone mineral density and bone mineral content at the lumbar spine, right hip, left hip, right femoral neck, and left femoral neck; prevalence of bone fracture; serum biochemical parameters; food and nutrient intake; and physical activity and smoking habits. Fasters did not differ from non-fasters in anthropometric measures (including height), bone mineral density and content, or prevalence of low bone mineral density at any of the five sites measured; number of bone fractures; or serum calcium or 25-hydroxyvitamin D concentrations (P > 0.05). Fasters had lower daily calcium and protein intakes, as well as lower dairy consumption than non-fasters. Groups did not differ in physical activity, and fasters smoked less than non-fasters.Conclusion: Despite lower calcium intake and lower dairy product consumption, individuals adhering to religious fasting since childhood did not differ in height, bone mineral density and content, or prevalence of fractures from controls. Therefore, periodic abstention from dairy and, generally, animal products since childhood does not seem to compromise bone health in young adults.What is Known: • Bone health is an important determinant of overall health and longevity. • Proper nutrition throughout childhood and adolescence is crucial for normal bone development. • Adequate intake of dairy products is considered important due to their high calcium content.What is New: • Young adults with limited calcium intake and dairy product consumption, due to adherence to the fasting rules of the Christian Orthodox Church since childhood, do not differ in height or indices of bone health from non-fasting controls.

Glycemic control and bone mineral density in children and adolescents with type 1 diabetes

BACKGROUND/OBJECTIVE

Fracture risk is increased in patients with type 1 diabetes. We aimed to evaluate bone mineral density (BMD) and to identify risk factors associated to lower BMD in Danish children and adolescents with type 1 diabetes.

METHODS

In this cross-sectional study BMD Z-score were determined by dual-energy X-ray absorptiometry (DXA) from a cohort of otherwise healthy children and adolescents with type 1 diabetes. Puberty Tanner stage, hemoglobin A1c (HbA1c), disease duration, and age at diabetes onset were investigated for associations to DXA results.

RESULTS

We included 85 patients, 39 girls, 46 boys, with a median (range) age of 13.2 (6-17) years; disease duration 4.2 (0.4-15.9) years; HbA1c of the last year 61.8 (41-106) mmol/mol. Our patients were taller and heavier than the background population. When adjusted for increased height SD and body mass index SD, no overall difference in BMD Z-score was found. When stratified by sex, boys had significantly increased adjusted mean BMD Z-score, 0.38 (95% confidence interval [CI]: 0.13;0.62), girls; -0.27 (95% CI: -0.53;0.00). For the whole cohort, a negative correlation between mean latest year HbA1c and BMD Z-score was found, adjusted ß -0.019 (95%CI: -0.034;-0.004, P = 0.01). Poor glycemic control (HbA1c > 58 mmol/mol [7.5%]) within the latest year was likewise negatively correlated with BMD Z-score, adjusted ß -0.35 (95%CI: -0.69;-0.014, P = 0.04).

CONCLUSIONS

Our study suggests that elevated blood glucose has a negative effect on the bones already before adulthood in patients with type 1 diabetes, although no signs of osteoporosis were identified by DXA.