Bone mineral density from early to middle adulthood in persons with Down syndrome.

BACKGROUND: While accelerated ageing is recognised among individuals with Down syndrome (DS), the trajectory of their bone health across adulthood remains poorly understood. METHODS: This study aimed to determine the age-related loss of bone mineral density (BMD) of the lumbar spine in 128 adults with DS aged 18 to 54 years compared with 723 counterparts without DS. RESULTS: Men and women with DS had lower level of BMD than counterparts without DS across age groups. Magnitude of decrement in BMD as reflected in the z-scores was similar between younger and older men with DS. Older women with DS, on the contrary, showed greater decrement in older ages especially in their fourth decade of life. Osteopenia and osteoporosis as defined using age-specific and gender-specific T-scores affected greater number of men with DS (38% and 25%) than women (17% and 17%) aged 40-49 years. CONCLUSIONS: Findings supported adults with DS, especially men, to have early bone mineral testing.

Fundamental movement skills and balance of children with Down syndrome.

BACKGROUND: Conclusive evidence supports the importance of fundamental movement skills (FMS) proficiency in promoting physical activity and countering obesity. In children with Down Syndrome (DS), FMS development is delayed, which has been suggested to be associated with balance deficits. This study therefore examined the relationship between FMS proficiency and balance ability in children with DS, with the aim of contributing evidence to programmes that address FMS delay. METHODS: Participants consisted of 20 children with DS (7.1 ± 2.9 years old) and an age-matched control group of children with typical development (7.25 ± 2.5 years). In the first part of the study, FMS (i.e. locomotor and object control) proficiency of the children was tested using the Test of Gross Motor Development-2. Balance ability was assessed using a force platform to measure centre of pressure average velocity (AV; mm/sec), path length (mm), medio-lateral standard deviation (mm) and antero-posterior standard deviation (mm). In the second part of the study, children with DS participated in 5 weeks of FMS training. FMS proficiency and balance ability were tested post-training and compared to pre-training scores. Verbal and visuo-spatial short-term memory capacities were measured at pre-training to verify the role of working memory in skill learning. RESULTS: FMS proficiency was associated with centre of pressure parameters in children with DS but not in children with typical development. After controlling for age, AV was found to predict significant variance in locomotor (R2  = 0.61, P < 0.001) and object control (R2  = 0.69, P < 0.001) scores. FMS proficiency and mastery improved after FMS training, as did AV, path length and antero-posterior standard deviation (all P < 0.05). Verbal and visuo-spatial short-term memory did not interact with the effects of training. CONCLUSIONS: Children with DS who have better balance ability tend to have more proficient FMS. Skill-specific training improved not only FMS sub-skills but static balance stability as well. Working memory did not play a role in the changes caused by skills training. Future research should examine the causal relationship between balance and FMS.

Adolescent testosterone, muscle mass and glucose metabolism: evidence from the 'Children of 1997' birth cohort in Hong Kong.

AIMS: Diabetes rates are high in Asia despite relatively low rates of obesity, which might be related to lower muscle mass. Muscle mass plays an important role in glucose metabolism. Peak muscle mass is obtained in late adolescence. We tested the hypothesis that pubertal testosterone is negatively associated with glucose metabolism mediated by muscle mass. METHODS: Participants aged 15 years (278 boys and 223 girls) were recruited from the Hong Kong's 'Children of 1997' birth cohort in 2012. Multivariable linear regression with multiple imputation and inverse probability weighting was used to examine the adjusted associations of pubertal testosterone with skeletal muscle index, body fat percentage, fasting glucose, insulin and homeostasis model of assessment - insulin resistance. RESULTS: Total testosterone was negatively associated with fasting glucose (-0.008, 95% confidence interval -0.015 to -0.002), insulin (-0.43, 95% confidence interval -0.56 to -0.30) and insulin and homeostasis model of assessment - insulin resistance (-0.09, 95% confidence interval -0.12 to -0.06) adjusted for sex, birth weight, highest parental education, mother's place of birth and physical activity. These associations were attenuated by additional adjustment for skeletal mass index or body fat percentage. CONCLUSIONS: Adolescent glucose metabolism may be influenced by testosterone, perhaps partially via skeletal muscle mass.