Opinion

Microvascular complications in diabetes mellitus are driven by chronic hyperglycemia. Their correlation with HbA_1c levels is considered useful; however, unlike the direct information provided by glucose, HbA_1c values reflect glycemic and nonglycemic factors. The author of this Perspective delineates the prominent roles of genetic and ethnic factors in determining HbA_1c variance and questions the usefulness of HbA_1clevels as a diagnostic tool for diabetes mellitus and prediabetes.

Disorders of the thyroid gland are relatively frequent in women of childbearing age and can result in poor pregnancy outcome. The authors of this Perspective are in favor of serum TSH measurement for all pregnant women and present relevant information on analytical and clinical aspects of serum TSH determination and its usefulness to detect subtle thyroid function abnormalities associated with the pregnant state, namely overt and subclinical hypothyroidism and hyperthyroidism.

HbA_1c is the cornerstone of diabetes management; however, measurement and interpretation of HbA_1c values is complex and hampered by lack of international standardization. The implementation of a reference system developed by the International Federation for Clinical Chemistry could potentially allow reporting of true HbA_1cresults, standardized to an absolute value, worldwide.

In this Perspective, De Graaf and Kok argue that two elements of contemporary eating that facilitate a high energy intake, namely a high eating rate and distraction of attention from eating, undermine the body's capacity to regulate its energy intake at healthy levels because they impair the congruent association between sensory signals during eating and the metabolic consequences after ingestion.

The ability of human embryonic stem cells to differentiate into pancreatic islet cells has defined the developmental stages and transcription factors involved in this process. As a consequence, refinement of gene and stem cell therapies for patients with insulin-dependent diabetes mellitus has become an area of intense research. In this Perspectives article, Calne and colleagues comment on the progress of these experimental therapies, which might one day become a clinical reality.

Many foods are marketed on the basis of a claim to reduce hunger, food intake or body weight. It is clear that any claim should be substantiated by scientific evidence. This article discusses the validity of such claims and the capacity of diet foods to influence behavior in a meaningful way in the real world.

The development of anti-obesity drugs has not been straightforward. With very few drugs on the market, and bad publicity related to adverse events, obesity remains a major challenge for the pharmaceutical industry. In light of past experience with endocannabinoid-system antagonists, such as rimonabant, the authors of this Perspectives article propose that a major paradigm shift in clinical practice might be necessary to justify the use of pharmacotherapy for obesity.

Knowledge of the epidemiology, natural history, diagnosis, treatment, and rates of recurrence of nonfunctioning pituitary adenomas has greatly improved over the past few years. Wass and Karavitaki now highlight some of these advances and speculate on future avenues of research. In addition, they describe their own experience in the clinical management of patients with nonfunctioning pituitary adenomas.