Reversion from type 2 diabetes to nondiabetic status. Influence of the 1997 American Diabetes Association criteria

OBJECTIVE: To determine the incidence and the rate of reversion of type 2 diabetes to a nondiabetic status in the 7- to 8-year follow-up of the San Antonio Heart Study, and to determine the influence of the recent 1997 American Diabetes Association (ADA) criteria for diabetes on these rates. Individuals who revert have been problematic for those developing criteria for the diagnosis of type 2 diabetes. Few studies have addressed this issue using 1979 National Diabetes Data Group/1980 World Health Organization (WHO) criteria. RESEARCH DESIGN AND METHODS: We studied 3,682 Mexican-American and non-Hispanic white men and nonpregnant women who completed both the baseline and follow-up examination of the San Antonio Heart Study. Incidence and reversion rates were calculated using both the 1980 WHO and the 1997 ADA criteria. Risk factors for reversion were identified, and the best fitting model using multiple logistic regression was determined using both the 1980 WHO and the 1997 ADA criteria. RESULTS: Using the 1997 ADA criteria, the age-adjusted incidences of type 2 diabetes for Mexican-American men and women were 10.8 and 12.2%, respectively. For non-Hispanic white men and women, the age-adjusted incidence rates were 5.5 and 5.1%, respectively. Similar age-adjusted incidences were recorded using the 1980 WHO criteria. The reversion rate for individuals with type 2 diabetes was 11.5% using the 1980 WHO criteria and 12.5% using the 1997 ADA criteria. These rates were not significantly different. Numerous risk factors for reversion were identified. The best fitting model, after controlling for age, sex, and ethnicity, included baseline 2-h glucose level, baseline HDL cholesterol, and previous diagnosis of diabetes. The models were the same for both the 1980 WHO and the 1997 ADA criteria. CONCLUSIONS: There was no significant difference in the incidence or the reversion rates for diabetic subjects using either 1980 WHO or 1997 ADA criteria. In addition, the risk factors for reversion were very similar using either set of criteria. The revision of the ADA criteria did not have a significant influence on reversion in this study.     

Proinsulin and insulin concentrations in relation to carotid wall thickness: Insulin Resistance Atherosclerosis Study

BACKGROUND AND PURPOSE: Insulin resistance and hyperinsulinemia have been associated with atherosclerosis. Recent attention has focused on the possible role of proinsulin because most radioimmunoassays for insulin cross-react with proinsulin. Therefore, it is not known which of the two, insulin per se or proinsulin, is more strongly related to atherosclerosis. METHODS: We examined the relation between fasting proinsulin, fasting split proinsulin, fasting and 2-hour insulin (after oral glucose load), and intima-media wall thickness (IMT) in the common carotid artery (CCA) and internal carotid artery (ICA) in 985 nondiabetic subjects from the Insulin Resistance Atherosclerosis Study, a multiethnic study of insulin resistance and atherosclerosis. RESULTS: In the overall population, a weak but significant relation between proinsulin and CCA IMT was observed (r=0.07, P=0.029). However, the relation between proinsulin and IMT was stronger in Hispanics and non-Hispanic whites than in African Americans. In non-Hispanic whites and Hispanics, significant correlations between CCA and proinsulin (r=0.087) and between ICA and proinsulin (r=0.101), split proinsulin (r = 0.092), and fasting insulin (r = 0.087) were observed. The significant correlations became more attenuated (and nonsignificant) after adjustment for cardiovascular risk factors, especially plasminogen activator inhibitor-1 (PAI-1). CONCLUSIONS: The association between proinsulin and IMT, while weak, appears to be stronger than the association between insulin and IMT. Adjustment for PAI-1 markedly attenuated the association between proinsulin and IMT, suggesting a possible mediating role for PAI-1 in this association. It is possible that proinsulin may represent a marker of atherosclerosis rather than a causal factor for atherosclerosis. Studies of the insulin resistance syndrome and atherosclerosis that use insulin as a surrogate for insulin resistance should consider the use of specific insulin assays as well as determination of proinsulin concentrations.     

Housing expenditure and housing policy in the West European rental sector

This contribution depicts therecent development of the housing expenditure quotefor various income groups in the social and privaterented sector in six West European countries. Thedevelopment reflects the similar policy efforts inthese countries, not only to reduce the regulatoryand subsidizing role of government but also topromote market mechanisms within the housing system.The analysis shows a recent rise in the gross aswell as the net rent quote in both rental sectors ofthe six countries. The one exception is the privaterented sector in Belgium. Despite the application ofhousing allowances, the lower-income groups have hadthe biggest increase in net rent quote. In addition,all six countries have recently seen an increase inthe concentration of low-income groups in the socialrented sector, where their presence was alreadystrong. If this trend persists, it will affect theposition of the social rented sector, the sociallandlords, but especially the low-income groups inboth the private and the social rented sector.     

User Costs and Housing Expenses. Towards a more Comprehensive Approach to Affordability

Recently housing affordability has reached the agenda in Flanders and the Netherlands, giving a good reason to present a review of the concept of affordability and different definitions. The concept of short-term affordability, which is concerned with financial access to a dwelling and is based on cash flows, is combined with the concept of long-term affordability, which is about the costs of housing consumption. The use of these concepts is illustrated for Flanders and the Netherlands. They show that each concept has its own uses and that they are not interchangeable. However, both concepts indicate that in 2005 higher-income households, and especially homeowners (with a mortgage), were relatively better off than lower-income households, particularly renters. Homeowners' higher income levels on average more than compensate for their higher expenses in comparison with tenants; they also receive higher explicit subsidization and in times of rising prices they also receive expected returns on housing.     

Performance assessment of housing associations

This article analyzes the function, design, and effects of a method to assess the performance of housing associations in the Netherlands. First, the roles of performance assessment are discussed from three perspectives: the association as an agent for the central government; the association as a facilitator of local stakeholders’ needs; and the association as an autonomous social entrepreneur. From each of these stereotypical perspectives, we derive the approaches to and functions of performance assessment. The resulting theoretical archetypes of performance assessment are then employed to analyze the method that was in place in 2005 in the Netherlands. The performance assessment system is also analyzed using the director, detector, and effector elements drawn from cybernetic theory. Furthermore, the Dutch performance assessment method is briefly compared with the English inspection system. This provides a better understanding of the types of performance assessment. In light of the identified perspectives on housing associations, we conclude that the Dutch method performs poorly on the director and effector element and that the English method performs relatively well on all elements. Nevertheless, in both countries adjustments in the performance assessment system can increase learning and improve the performance of housing associations.     

Predicting diabetes. Moving beyond impaired glucose tolerance

We developed predictive models for type II diabetes using stepwise multiple logistic regression analyses of a cohort of 844 Mexican Americans and 641 non-Hispanic whites who were nondiabetic at baseline and who were then followed for 8 yr. Models were developed for the overall population and separately for each sex and ethnic group. For optimal models, the multiple logistic regression program selected potential risk factors from a panel of 5 categorical and 14 continuous demographic, anthropometric, metabolic, and hemodynamic variables. For reduced models, the list of candidate variables was restricted to those commonly used in ordinary clinical practice, i.e., skinfolds, and serum insulin and postural glucose load variables were excluded. For all models, the stepwise process selected a mixture of anthropometric, glucose, lipid, and hemodynamic variables. The top 15% of the risk continuum for each model was defined as high risk to compare the performance of the models with the performance of impaired glucose tolerance (15% prevalence) as a predictor of diabetes. The relative risk of being high risk ranged from 12.16 to 35.29, whereas the relative risk of having impaired glucose tolerance ranged from 7.11 to 10.0. The sensitivity of the multiple logistic regression models ranged from 67.7 to 83.3% compared with 56.5 to 62.1% for impaired glucose tolerance. The results indicate that multivariate predictive models perform at least as well, if not better than impaired glucose tolerance in predicting type II diabetes but need not require an oral glucose load. Moreover, the models highlight the complex metabolic and hemodynamic syndrome that precedes diabetes.     

Plasma-associated halogenated phenolic contaminants in benthic and pelagic fish species from the Detroit River

Halogenated phenolic contaminants (HPCs), polychlorinated biphenyls (PCBs), and other organochlorine (OC) contaminants (DDTs, chlordanes, HCH, and octachlorostyrene (OCS)) were determined (ng/g, wet wt basis) in the blood plasma of 6 piscivorous/pelagic- and 7 benthic-feeding fish species from the Detroit River. Seven to twelve hydroxylated (OH) PCB congeners with pentachloro- to nonachloro-substitution, pentachlorophenol (PCP) and 4-OH-heptachlorostyrene (4-OH-HpCS), as well as a number of other unidentified HPCs, were detected in all the fish species studied. The concentrations of sigma-OH-PCB (0.57-129.5 ng/ g), 4-OH-HpCS (0.02-0.31 ng/g), and PCP (0.05-3.42 ng/ g) in comparison to other major polychlorinated contaminants (sigma-PCB (10.4-909.0 ng/g), sigma-chlordane (0.72-8.68 ng/g), sigma-DDT (2.10-66.57 ng/g), and sigma-HCH (0.04-0.84 ng/g)) demonstrate the importance of HPCs, especially OH-PCBs, as plasma-associated contaminants. OH-PCBs are most likely metabolites of PCBs, and 4-OH-HpCS is a likely metabolite of OCS. Our findings indicate that metabolic biotransformation is a factor in the bioaccumulation, pharmacokinetics, and fate of OCS and highly chlorinated PCB congeners that are generally more recalcitrant in fish. Target tissue exposure to circulating OH-PCBs was variable, and thus potential OH-PCB-mediated toxicological activity and effects (e.g., endocrine-related) and health risks are different among the fish species.     

Ecological Significance of Upwelling Events in Lake Ontario

Upwelling events in Lake Ontario were studied to determine (1) their significance as mechanisms to provide nutrients from the hypolimnion to the epilimnion and (2) their impact on resident plankton communities of the nearshore zone. It was concluded that such events did not result in sufficient mixing to recharge nutrient stocks of these areas. Upwellings were characterized as being temporal displacements of nearshore water masses which returned at the end of each event. Plankton communities of the nearshore area were displaced with the water mass and therefore received little or no benefit from the upwelled nutrient rich hypolimnetic waters. Evidence is provided to suggest that diatom species such as Asterionella formosa Hass and Fragilaria crotonensis Kitton were able to grow in the upwelled hypolimnetic water, and upwellings might be a mechanism to inoculate these species into the epilimnion of deep lakes prior to the autumn overturn. Upwelling events also caused rapid shifts in the species composition of zooplankton communities. Such shifts were particularly pronounced within 1 km of the shoreline.