Lifestyle and type 2 diabetes ― small changes, substantial impact
What can people do to improve their health after they’ve been diagnosed with type 2 diabetes? This question is becoming all the more urgent as cases of diabetes continue to rise. In this Diabetes Awareness Week (9-14 June), Paul Browne, communications managerat the MRC Epidemiology Unit in Cambridge, rounds up some recent research from the unit suggesting that small lifestyle changes made soon after diagnosis can make a big difference.
Research published this week has highlighted the increased number of people in the UK with pre-diabetes and type 2 diabetes, reinforcing the urgent need to find ways of preventing and treating the disease.
We know that changes to diet are important for controlling blood glucose levels and reducing risk factors for cardiovascular disease such as high blood pressure and high cholesterol levels.
But there hasn’t been much research into whether lifestyle changes made soon after diagnosis with type 2 diabetes, can result in long-term health benefits. There has also been a lack of good-quality evidence for the benefit of combining lifestyle changes and medication, over and above medication alone.
This is important because for many individuals, the most challenging aspect to managing their diabetes is adopting and maintaining a healthy lifestyle. They may believe that lifestyle is less important than medication, or that the health benefits are not sufficient to justify the effort and disruption to their daily lives. Some may even feel that taking medication such as statins for cholesterol means that they can disregard dietary advice.
Ultimately it comes down to a simple question: “Will this make a difference?”
A decade ago researchers in the UK joined colleagues in Denmark and the Netherlands to answer to that question. ADDITION is a study of people aged 40-69 years in these three countries who were invited to a blood glucose screening test by their general practitioner. Those found to have type 2 diabetes were invited to enter a randomised controlled trial comparing the long-term effects of standard type 2 diabetes treatment (medication) with a combination of standard treatment plus educational materials on healthy diet, physical activity and smoking.
Of particular interest to the unit’s Prevention of Diabetes and Related Metabolic Disorders team, led by Simon Griffin and Rebecca Simmons, was whether or not behavioural changes in people with newly-diagnosed diabetes could reduce the subsequent risk of events such as heart attacks and strokes, or the need for surgery such as coronary angioplasty or bypass surgery.
To determine this, they assessed the physical activity levels, diet and alcohol consumption of the 867 ADDITION participants in Cambridge at the beginning of the study, and again one year after diagnosis. The members of the group were then studied for about five years.
The results of their work, published in two papers earlier this year, provide strong evidence that adopting a healthy lifestyle really does make a difference.
In the first paper, Grainne Long and colleagues reported in the journal Diabetes Care that people with newly diagnosed diabetes who adopted healthy behaviour changes had a lower risk of experiencing a heart attack or stroke over the five years. The greater the number of healthy behaviour changes made in the first year after diabetes diagnosis, the lower the risk (1). Compared to individuals who changed three or four behaviours, those who changed just two were 70 per cent more likely to have a heart attack or stroke, while people who changed just one or none were almost four-times more likely.
The behavioural changes which had the greatest effect were increasing physical activity and reducing alcohol intake. The benefits were seen in all groups of patients: older and younger, male and female, people from different social groups and people taking several or few medications.
In the second paper, published in the European Journal of Clinical Nutrition, individuals who made small but achievable changes to their diet over the first year following diagnosis experienced reductions in a number of cardiovascular risk factors, most notably blood pressure and levels of fats called triglycerides in the blood (2). What’s more, the investigators showed that these reductions were similar among all individuals, regardless of whether or not they were taking diabetes-specific medication.
Lead author Andrew Cooper notes that the dietary changes are practical for most patients: “Our findings demonstrate that modest and achievable dietary changes, equating to substitution of a chocolate bar for a piece of fruit and half a teaspoon less of salt per day, really are important for improving health in diabetes”.
And this is the key message for both patients with diabetes and medical practitioners to take from the two papers: modest behavioural changes made within the first year after diabetes diagnosis do make a difference over the longer term.
ADDITION-Cambridge was funded by the MRC, Wellcome Trust and the National Institute for Health Research.
1) Cooper AJ et al. Do improvements in dietary behaviour contribute to cardiovascular risk factor reduction over and above cardio-protective medication in newly diagnosed diabetes patients? Eur J Clin Nutr. 2014 doi: 10.1038/ejcn.2014.79.
2) Long GH et al. Healthy Behavior Change and Cardiovascular Outcomes in Newly Diagnosed Type 2 Diabetic Patients: A Cohort Analysis of the ADDITION-Cambridge Study Diabetes Care 2014 doi: 10.2337/dc13-1731 PMID:24658389.