Growth hormone effects on cortical bone dimensions in young adults with childhood-onset growth hormone deficiency

UNLABELLED: Growth hormone (GH) treatment in young adults with childhood-onset GH deficiency has beneficial effects on bone mass. The present study shows that cortical bone dimensions also benefit from GH treatment, with endosteal expansion and increased cortical thickness leading to improved bone strength. INTRODUCTION: In young adults with childhood-onset growth hormone deficiency (CO GHD), GH treatment after final height is reached has been shown to have beneficial effects on spine and hip bone mineral density. The objective of the study was to evaluate the influence of GH on cortical bone dimensions. METHODS: Patients (n = 160; mean age, 21.2 years; 63% males) with CO GHD were randomised 2:1 to GH or no treatment for 24 months. Cortical bone dimensions were evaluated by digital x-ray radiogrammetry of the metacarpal bones every 6 months. RESULTS: After 24 months, cortical thickness was increased compared with the controls (6.43%, CI 3.34 to 9.61%; p = 0.0001) and metacarpal index (MCI) (6.14%, CI 3.95 to 8.38%; p < 0.0001), while the endosteal diameter decreased (-4.64%, CI -7.15 to -2.05; p < 0.001). Total bone width did not change significantly (0.68%, CI -1.17 to 2.57%; not significant (NS)). A gender effect was seen on bone width (p < 0.0001), endosteal diameter (p < 0.01) and cortical thickness (p < 0.01), but not with MCI (NS). CONCLUSIONS: Cortical bone reacts promptly to reinstitution of GH beyond the attainment of final height by increasing the cortical thickness through endosteal bone growth. This leads to a higher peak bone mass and may reduce the risk of cortical bone fragility later in life

The elephant in the room: the role of time in expatriate adjustment

This conceptual article explores the role of temporal dynamics in the study of expatriate adjustment. We introduce the dimensions and the domains of adjustment and discuss the dynamics between them, as well as the dynamics between antecedents, state and consequences of adjustment. Issues such as the role of time lags, duration and rate of change as well as reciprocal causation are discussed. We address the consequences of these issues for theory building in the area of expatriate adjustment and the implications for methodological choices. We conclude with specific recommendations for the future research of expatriate adjustment that recognise the nature of adjustment as a process evolving over time and that we hope will enhance the rigour and relevance of this area of research