ADA research news: fewer people will get type 2 and gestational diabetes

22 years of type 2 prevention

The Diabetes Prevention Program (DPP) was a major U.S. study that changed the way we approach type 2 diabetes prevention worldwide. It showed that people who are at high risk of type 2 diabetes can prevent or delay the condition by losing weight through dietary changes and increased physical activity. Taking metformin was also found to help prevent type 2, though to a lesser degree.

The ongoing DPP Outcomes Study (DPPOS) has continued to follow most of the original DPP participants since it ended in 2002, making it one of the world’s longest and largest type 2 prevention study. It aims to understand more about the long-term effects of the lifestyle and metformin interventions on the development of type 2 diabetes and its complications. And as the average age of the participants is now 72 years, the DPPOS has started to investigate contributors to healthy ageing and other health conditions, like cancer.

The latest results presented at the ADA show that 22 later benefits are still being seen. There was a 25% reduced risk of developing type 2 in the group supported to make dietary and activity changes, and a 18% reduced risk for those taking metformin, compared with people who took a placebo.

The researchers didn’t see any differences between the lifestyle and metformin groups for risk of developing diabetes complications, including heart disease, kidney disease or retinopathy. But the results did suggest that in a subgroup of people who joined the study and started taking metformin before the age of 45, there was a reduction in strokes and heart attacks.

They also found that the lifestyle group had a long-term reduction in the development of frailty. Fragility describes how our bodies lose their ability to ‘bounce back’ as we get older, and can be linked with a higher risk of falls, admission to hospital, or the need for long-term care. The metformin group also had a slightly smaller risk of cancer compared with the placebo group. But this could be down to random chance rather than the effects of metformin, so we’d need more research to look into this.

The only long-term negative effect observed with any of the interventions was a small increase in kidney disease with metformin, which appeared only in the oldest group of participants.

Not only do these latest results show the power of these interventions to continue to prevent type 2 diabetes over a long time period, but they also suggest that approaches to prevent type 2 could have other health benefits.

Plant power to prevent gestational diabetes

Plant-based diets have been linked with lower levels of type 2 diabetes and cardiovascular disease. They tend to be lower in saturated fat, higher in fibre and other protective substances, like antioxidants and vitamins. And it’s believed these benefits can help with weight loss, blood sugar control, improve blood fats and pressure, reduce inflammation and boost gut health.

Although type 2 and gestational diabetes share some of the same risk factors, gestational diabetes also has unique risks, such as changing levels of hormones during pregnancy. Therefore researchers didn’t know whether a plant-based diet could also help to prevent gestational diabetes.  

This is what Dr Frank Qian and a team at Harvard University set to find out. They looked at 15,999 women who become pregnant over a 10-year period, 846 of whom developed gestational diabetes. The women completed questionnaires every four years on their diet. From this, the researchers calculated how much of their diet was plant-based. They also worked out separate scores on the extent participants stuck to a healthy plant-based diet or a less healthy one – eating more foods high in salt, sugar and fat.

The scientists found that women with diets higher in plant-based foods had a 30% lower risk of developing gestational diabetes compared to those with the lowest amount of plant-based meals. And a healthy plant-based diet was found to be even more beneficial. But when they took into account differences between the women in pre-pregnancy body mass index (BMI) this effect became less strong. This suggests – in a large part – it’s likely to be the impact a plant-based diet has on someone’s weight which explains the link with a reduced risk of gestational diabetes.

There’s still more to work out about how helpful plant-based diets, and other dietary options, could be for women at high risk of gestational diabetes. And Dr Qian will also be looking at eating habits during pregnancy, to figure out if what we eat then also influences risk for gestational diabetes.

When it comes to diet it’s all about making it work for you, but upping plant-based foods could be one way to help make sure fewer women develop gestational diabetes.  

Better prediction of type 2 risk

Preventing gestational diabetes is also vital because we know women who’ve had the condition have a seven-fold higher risk of going on to develop type 2 diabetes in the future. If we could spot those who are most likely to get type 2 early on they could be supported to lower their risk. But at the moment we don’t have very good ways doing this.

Dr Mugdha Joglekar, at the University of Sydney, thinks microRNAs could lend a helping hand. MicroRNAs are molecules that scientists can look for in our blood. They play a key role in silencing genes and could signal that biological processes that lead to development of type 2 diabetes are underway. Dr Joglekar wanted to know if there were any differences in microRNAs between women who had gestational diabetes and later went on to develop type 2, versus those that didn’t.

She recruited 103 women with gestational diabetes, who all returned to having healthy blood sugar levels after giving birth. They were followed over an 8-year period to see if anyone was diagnosed with type 2 diabetes. 21 women were.

The research team used blood samples they’d collected 12 weeks after the women gave birth to study their microRNA profile. They discovered four microRNAs that showed a very different profile between those who did and didn’t develop type 2 diabetes.

They then asked if using these could help to improve risk prediction for future type 2. They found looking at the microRNAs was just as effective at calculating risk for women with gestational diabetes as the clinical features that doctors currently use (age, BMI, blood sugar levels and cholesterol). And when the microRNAs were added on top of the clinical features it improved the ability to predict who would go on to develop type 2 diabetes.

Dr Joglekar noted that they only had limited samples and there’s a need to replicate their work in bigger studies. But improved prediction will help us make sure those at greatest risk can be supported early on to reduce it and potentially avoid type 2 diabetes.