Type 2 diabetes and obesity -- what do we really know?

October 06, 2016

Social and economic factors have led to a dramatic rise in type 2 diabetes and obesity around the world. In a review in Science, Mark McCarthy, professor at the University of Oxford, UK, and Paul Franks, professor at Lund University, Sweden, examine the knowledge of the actual causes and the interplay between genetics and lifestyle factors.

By studying how our genes express themselves in response to environmental factors and changes in lifestyle, we will better understand how health recommendations and treatments can be tailored to each individual.

"Environmental factors that disturb cellular and physiological processes and have an effect on the individual's predisposition to diseases, such as type 2 diabetes, are likely to do so through active, and reactive, modulation of genome function. There is a compelling rationale behind this concept, but the details about how these processes work remain poorly defined", says Paul Franks.

"However, there is emerging evidence that epigenomic changes such as DNA methylation and histone modifications, which affect the ways in which genes are transcribed and translated into proteins, are important features of these processes", he continues.

Previous research has largely focused on dietary components and which diet would be best to lower the risk of obesity and type 2 diabetes, but so far there is no clear evidence from epidemiological or clinical trial data that a specific diet is optimal for long-term weight-loss or lowering the risk of diabetes. Some types of dietary fat may be harmful while others may in fact be protective. The researchers also concluded that the widely established view that vitamin D supplementation lowers blood sugar levels and the risk of type 2 diabetes is unlikely to be accurate.

In recent years, there has been an explosion of interest in the role of the gut microbiome in the development of type 2 diabetes and obesity.

"Several studies have detected differences in the composition of the gut microbiome between healthy people and those with obesity and type 2 diabetes, but the cause and effect remain unclear", says Mark McCarthy, and continues:

"In addition, both high and low birth weight have been linked to type 2 diabetes later in life. It seems as if these associations reflect the complex interplay of genetic variation in both the foetus and the mother, along with the impact of the intrauterine environment."

The major challenge is getting closer to a mechanistic understanding of why type 2 diabetes and obesity occur and why they have become so much more common in the last 40-50 years.

"We have only a superficial understanding of that. It often gets blamed on our western lifestyle but the specific components of modern life that are most damaging remain unclear. We also know that this occurs on the background of hundreds of genetic differences that influence predisposition. The genetic findings are increasingly allowing us to understand the mechanisms involved, and to start to connect the genetic and environmental contributions", says Mark McCarthy.

Facts/Type 2 diabetes

The rising prevalence of type 2 diabetes and obesity constitute major threats to human health around the world. About ten per cent of the global population already have type 2 diabetes, or are likely to develop it, and 40 per cent of adults are overweight or obese. The heritability for obesity and type 2 diabetes is 70 and 35 per cent respectively. The western lifestyle represents a culprit with a combination of excess calories, physical inactivity, sleep deprivation, endocrine disorders and smoking. More research is needed to figure out which of the elements of our lifestyle are important to define more effective interventions.
-end-
Contact:

Mark McCarthy, University of Oxford, UK, mark.mccarthy@drl.ox.ac.uk or +44 (0)7825 344066
Paul Franks, Lund University, Sweden, paul.franks@med.lu.se or +46 (0)7030 45755

Lund University

Related Diabetes Articles from Brightsurf:

New diabetes medication reduced heart event risk in those with diabetes and kidney disease
Sotagliflozin - a type of medication known as an SGLT2 inhibitor primarily prescribed for Type 2 diabetes - reduces the risk of adverse cardiovascular events for patients with diabetes and kidney disease.

Diabetes drug boosts survival in patients with type 2 diabetes and COVID-19 pneumonia
Sitagliptin, a drug to lower blood sugar in type 2 diabetes, also improves survival in diabetic patients hospitalized with COVID-19, suggests a multicenter observational study in Italy.

Making sense of diabetes
Throughout her 38-year nursing career, Laurel Despins has progressed from a bedside nurse to a clinical nurse specialist and has worked in medical, surgical and cardiac intensive care units.

Helping teens with type 1 diabetes improve diabetes control with MyDiaText
Adolescence is a difficult period of development, made more complex for those with Type 1 diabetes mellitus (T1DM).

Diabetes-in-a-dish model uncovers new insights into the cause of type 2 diabetes
Researchers have developed a novel 'disease-in-a-dish' model to study the basic molecular factors that lead to the development of type 2 diabetes, uncovering the potential existence of major signaling defects both inside and outside of the classical insulin signaling cascade, and providing new perspectives on the mechanisms behind insulin resistance in type 2 diabetes and possibly opportunities for the development of novel therapeutics for the disease.

Tele-diabetes to manage new-onset diabetes during COVID-19 pandemic
Two new case studies highlight the use of tele-diabetes to manage new-onset type 1 diabetes in an adult and an infant during the COVID-19 pandemic.

Genetic profile may predict type 2 diabetes risk among women with gestational diabetes
Women who go on to develop type 2 diabetes after having gestational, or pregnancy-related, diabetes are more likely to have particular genetic profiles, suggests an analysis by researchers at the National Institutes of Health and other institutions.

Maternal gestational diabetes linked to diabetes in children
Children and youth of mothers who had gestational diabetes during pregnancy are at increased risk of diabetes themselves, according to new research published in CMAJ (Canadian Medical Association Journal).

Two diabetes medications don't slow progression of type 2 diabetes in youth
In youth with impaired glucose tolerance or recent-onset type 2 diabetes, neither initial treatment with long-acting insulin followed by the drug metformin, nor metformin alone preserved the body's ability to make insulin, according to results published online June 25 in Diabetes Care.

People with diabetes visit the dentist less frequently despite link between diabetes, oral health
Adults with diabetes are less likely to visit the dentist than people with prediabetes or without diabetes, finds a new study led by researchers at NYU Rory Meyers College of Nursing and East Carolina University's Brody School of Medicine.

Read More: Diabetes News and Diabetes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.