Blood pressure reduction is an effective way to reduce the risk of developing type 2 diabetes in the future, according to research funded by the British Heart Foundation (BHF) and published today in The Lancet.
Doctors already prescribe blood pressure-lowering medications to reduce a person’s chance of having a life-threatening heart attack or stroke, but whether these drugs are helpful to stave-off diabetes has been previously unknown.
This new study reveals that the protective effect of such medication is wider reaching and may also reduce a person’s risk of developing type 2 diabetes. The charity Diabetes UK estimates that 13.6 million people in the UK are at high risk of developing type 2 diabetes.
In the most detailed study to date of over 145,000 people from 19 randomised clinical trials across the world, researchers at the University of Oxford and the MRC Integrative Epidemiology Unit found that a 5 mmHg reduction in systolic blood pressure – which is easy to achieve through lifestyle changes, diet modifications or antihypertensive medication – reduced the risk of type 2 diabetes by 11 per cent. All participants were followed up for an average of 4.4 years and 9883 people developed type 2 diabetes.
This risk reduction was also confirmed using a genetic data analysis approach called Mendelian randomisation, which uses naturally occurring genetic differences to randomly divide participants into groups, mimicking the effects of running a clinical trial. People with genetically influenced lower blood pressure level had a 12% lower risk of type 2 diabetes compared to those without these genetic associations.
In addition to the effect of blood pressure reduction itself, the team then investigated the effects of five major types of blood pressure drugs from 22 clinical trials compared to a placebo. They found angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor-II blockers (ARBs) had the strongest protective effect on the development of type 2 diabetes, both reducing the relative risk by 16 per cent.
Other types of blood pressure-lowering drugs were not protective - calcium channel blockers had no effect on diabetes risk, while beta-blockers and thiazide diuretics increased the risk, (despite their known beneficial effects for prevention of stroke and heart attack). This opposing effect of different types of drugs on diabetes is most likely due to the different ways they act in the human body, independent of their effect on blood pressure.
With consistent results from both randomised controlled trials and genetic analyses, this research has shown that lowering blood pressure can prevent type 2 diabetes, with an effect size that was similar to that seen for the prevention of major cardiovascular disease. Current recommendations to reduce the risk of diabetes is to keep a healthy weight and stick to a healthy lifestyle. Now, the researchers say that reducing blood pressure through lifestyle changes and specific blood pressure drugs (ACE inhibitors and ARBs) should now be considered in the treatment plan for some patients who are at higher risk of type 2 diabetes.
Paper:
'Blood pressure lowering and risk of new-onset type 2 diabetes: an individual-level meta-analysis of 145,000 randomized participants’. by Milad Nazarzadeh, George Davey Smith et al, in The Lancet