Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes

BACKGROUND: Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible association between prevalence of adolescent idiopathic scoliosis and age at menarche among normal girls in various geographic latitudes. An attempt is also made to implicate a possible role of melatonin in the above association. MATERIAL-METHODS: 20 peer-reviewed published papers reporting adolescent idiopathic scoliosis prevalence and 33 peer-reviewed papers reporting age at menarche in normal girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included regression of the adolescent idiopathic scoliosis prevalence and age at menarche by latitude. RESULTS: The regression of prevalence of adolescent idiopathic scoliosis and age at menarche by latitude is statistically significant (p < 0.001) and are following a parallel declining course of their regression curves, especially in latitudes northern than 25 degrees. CONCLUSION: Late age at menarche is parallel with higher prevalence of adolescent idiopathic scoliosis. Pubarche appears later in girls that live in northern latitudes and thus prolongs the period of spine vulnerability while other pre-existing or aetiological factors are contributing to the development of adolescent idiopathic scoliosis. A possible role of geography in the pathogenesis of idiopathic scoliosis is discussed, as it appears that latitude which differentiates the sunlight influences melatonin secretion and modifies age at menarche, which is associated to the prevalence of idiopathic scoliosis

Efficient allocations in economies with asymmetric information when the realized frequency of types is common knowledge

We consider a general economy, where agents have private information about their types. Types can be multidimensional and potentially interdependent. We show that, if the realized frequency of types (the exact number of agents for each type) is common knowledge, then a mechanism exists, which is consistent with truthful revelation of private information and which implements first-best allocations of resources as the unique equilibrium. The result requires the single-crossing property on utility functions and the anonymity of the Pareto correspondence

Macroeconomic and industry-specific determinants of Greek bank profitability

Purpose: The purpose of this paper is to investigate the external factors that influence the profitability of a typical Greek systemic bank over the period 2001 – 2014. Design/Methodology/Approach: A conceptual framework incorporating two fundamental groups of const ructs, namely, macroeconomic forces and industry related factors, was developed. Two constructs were examined in the former: GDP growth rate and unemployment rate, whilst two attributes were explored in the latter; the bank's market share, both in terms of deposits and in terms of assets, and the banking market growth, also both in terms of the market's total assets and total deposits. In order to isolate the effects of the ongoing financial crisis, the research was undertaken for two periods, firstly 2001 to 2014 and secondly, the period 2001 - 2011, which excluded the deep recession. Consequently, multiple regression analysis was conducted and linear models were specified by means of OLS. Findings: The empirical analysis revealed that both macroeconomic forces and industry-related factors affect bank profitability. As far as the macroeconomic factors are concerned, unemployment rate has a negative impact, whereas the GDP growth rate has a positive impact on bank profitability. The industry -related factors, rate of growth of the industry's deposits and bank's assets market share have a positive impact on the financial performance of the bank. Finally, the rate of growth of the industry's assets and the bank's deposits market share have a negative effect on bank profitability. Originality/Value: This study reveals the mechanism determining bank profitability over a recent period that includes the financial crisis. Moreover, understanding the impact of macroeconomic forces as well as industry related attributes on bank profitability may enable banks to focus on the most critical factors in their decision process

Supply of capital and capital structure: The role of financial development

We explore the effect of financial development on corporate capital structure and the tightness of financial constraints that firms face. We employ an econometric technique that allows us to explicitly test for convergence in capital structure. This technique increases the power of our statistical tests. In doing so, we identify a group of convergent firms. The driving force of convergence is financial development, which positively affects the firms' leverage ratio. We also identify a group of firms, whose leverage is not affected by financial development, because they are financially constrained