Predictors of trabecular bone score in school children.

UNLABELLED: Trabecular bone score (TBS) is a DXA-based tool that assesses bone texture and reflects microarchitecture. It has been shown to independently predict the risk of osteoporotic fracture in the elderly. In this study, we investigated the determinants of TBS in adolescents. INTRODUCTION: TBS is a gray-level textural measurement derived from lumbar spine DXA images. It appears to be an index of bone microarchitecture that provides skeletal information additional to the standard BMD measurement and clinical risk factors. Our objectives were to characterize the relationship between TBS and both age and pubertal stages and identify other predictors in adolescents. METHODS: We assessed TBS by reanalyzing spine DXA scan images obtained from 170 boys and 168 girls, age range 10-17 years, gathered at study entry and at 1 year, using TBS software. The results are from post hoc analyses obtained using data gathered from a prospective randomized vitamin D trial. Predictors of TBS were assessed using t test or Pearson's correlation and adjusted using regression analyses, as applicable. RESULTS: The mean age of the study population was 13.2 ± 2.1 years, similar between boys and girls. Age, height, weight, sun exposure, spine BMC and BMD, body BMC and BMD, and lean and fat mass are all significantly correlated with TBS at baseline (r = 0.20-0.75, p < 0.035). Correlations mostly noted in late-pubertal stages. However, after adjustment for BMC, age remained an independent predictor only in girls. CONCLUSIONS: In univariate exploratory analyses, age and pubertal stages were determinants of TBS in adolescents. Studies to investigate predictors of TBS and to investigate its value as a prognostic tool of bone fragility in the pediatric population are needed.

Expanding to institutionally different countries. Reasons, Firm International Experience, and Entry Mode Choice

We examine entry mode choice and its consequences when a multinational enterprise (MNE) expands into an institutionally different country. We argue that discussions of entry mode should distinguish between informal (e.g., culture) and formal (e.g., laws) institutions, and should take into account not just the home country of the MNE and its distance to the focal host country, but the MNE's overall footprint and experience across the world in general, especially in countries with an institutional structure that is similar to that of the focal host country. Specifically, we argue that firms with experience in countries with different informal institutions will be more likely to enter via acquisitions than firms without such experience, that such experience will not matter as much in the case of formal institutions, and that such firms will exit more quickly when they enter via equity alliances than through full acquisitions. We also distinguish between balanced and unbalanced alliances and argue that balanced alliances will be more enduring, but only when the host country is culturally (not legally) different from the other countries where the MNE has experience. Our arguments suggest that entry mode should be conditioned on a firm's experience in other markets, and that intercountry differences in formal versus informal institutions have distinct influences on entry mode.