Relation of central adiposity and body mass index to the development of diabetes in the Diabetes Prevention Program.
ABSTRACT Greater central adiposity is related to the risk of diabetes.
We aimed to test the hypothesis that central adiposity measured by computed tomography (CT) is a better predictor of the risk of diabetes than is body mass index (BMI), waist circumference (WC), waist/hip ratio (WHR), or waist/height ratio.
Visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured at the L2-3 and L4-5 disc spaces in 1106 of the 3234 participants in the Diabetes Prevention Program. Sex-specific proportional hazards models were used to evaluate the association between VAT and SAT at both cuts, BMI, and other measures of central adiposity as predictors of the development of diabetes.
Men had more VAT than did women. White subjects had more VAT at both cuts than did other ethnic groups. The ratio of VAT to SAT was lowest in African Americans of both sexes. Among men in the placebo group, VAT at both cuts, WC, BMI, waist/height ratio, and WHR predicted diabetes (hazard ratio: 1.79-1.44 per 1 SD of variable). Among women in the lifestyle group, VAT at both cuts predicted diabetes as well as did BMI, and L2-3 was a significantly better predictor than was WC or WHR. SAT did not predict diabetes. None of the body fat measurements predicted diabetes in the metformin group.
In the placebo and lifestyle groups, VAT at both cuts, WHR, and WC predicted diabetes. No measure predicted diabetes in the metformin group. CT provided no important advantage over these simple measures. SAT did not predict diabetes.
Article: Molecular bases of myelin formation as revealed by investigations on mice deficient in glial cell surface molecules.[show abstract] [hide abstract]
ABSTRACT: Several glia-associated cell surface molecules have been implicated in myelin formation in the central (CNS) and peripheral nervous system (PNS). Recent studies in mice deficient for such molecules have been instrumental in understanding the role of these molecules during the formation of the spiraling loops around the axon, compaction of the spiraling loops, determination of the thickness of the myelin sheath, and myelin maintenance. In the PNS, the major peripheral myelin protein PO and the peripheral myelin protein (PMP) 22 are involved in spiral formation as reflected by retarded myelin formation in mice deficient for the respective molecules. An involvement of the myelin-associated glycoprotein (MAG) in this process is detectable only in mice deficient in both PO and MAG, suggesting that PO can replace MAG during the formation of the spiraling loops. Myelin compaction is mediated by both PO and the intracellular myelin component myelin basic protein (MBP). The determination of the correct myelin thickness is mediated by PO, MBP, and PMP22, with PO and MBP fostering and PMP22 attenuating myelin growth. For the maintenance of the association of the Schwann cell and myelin with its ensheathed axon, the myelin components PO, PMP22, MAG, and Connexin 32 are crucial. In the CNS, recognition of oligodendrocytes and axons and the formation of the spiraling loops is mediated by MAG. MAG is additionally responsible for the maintenance of myelin. Myelin compaction is mediated by MBP and by PLP, which fulfills some analogous functions in the CNS as PO in the PNS. These studies reveal that myelin-related cell surface molecules can play distinct but also partially overlapping roles during the formation and maintenance of myelin.Glia 05/1997; 19(4):298-310. · 4.82 Impact Factor