Obesity, high blood sugar, blood pressure and low-density lipoprotein (LDL, ‘bad’) cholesterol are risk factors for cardiovascular disease (CVD) – the leading cause of premature death in people with type 2 diabetes (T2D). Numerous research shows that the most effective way to lower CVD risk, prevent diabetes-related complications and improve life quality is to maintain tight control of these risk factors.
A new modelling study has further shown that people with diabetes can dramatically increase their lifespan by lowering and maintaining control of these risk factors. Remarkably, people with very high HbA1c, LDL-cholesterol, blood pressure and BMI can increase their lifespan by at least ten years if they lower and achieve reasonable control of these biomarkers.
The study, “Potential Gains in Life Expectancy Associated with Achieving Treatment Goals in US Adults with Type 2 Diabetes,” was published in JAMA Network Open.
The study used data from the 2015-2016 National Health and Nutrition Examination Survey (NHANES) and included American adults aged 51-80 years with diabetes. Participants provided demographic data, smoking status, HbA1c, blood pressure, LDL-C and BMI measurements. Then with the BRAVO diabetes model, the researchers used each participant’s risk profile to predict long-term health outcomes, including diabetes-related complications and death.
A total of 421 individuals (46% women) with a mean age of 65 were enrolled. The participant’s BMI, HbA1c, blood pressure, and LDL-cholesterol levels were analysed and split into four groups. Those with the highest measurements for each risk factor were placed in the fourth group and those with the lowest in the first group.
Reducing HbA1c from 9.9% (the mean of the fourth group) to 7.7% (the mean of the third group) was linked to an average increase of 3.4 years in lifespan. Further reducing HbA1c from the third group to the second group (mean of 6.8%) was associated with a mean increase of half a year. Interestingly, reducing it from the second to the lowest group (5.9%) did not prolong lifespan and instead decreased it by 0.1 years. Overall, reducing HbA1c from an average of 9.9% to 5.9% was associated with a 3.8-year increase in lifespan.
Compared with individuals with a BMI of 41.4 (mean of the fourth group), a lower BMI of 24.3 (mean of the first group) was linked with a 3.9-year increase in lifespan. Individuals with a lower BMI of 33.0 and 28.6 had a 2.0 and 2.9-year increase in lifespan, respectively, compared to those with a BMI of 44. Similar results were seen with blood pressure and LDL cholesterol. Specifically, individuals with the lowest blood pressure had a 1.9-year longer lifespan than those with the highest blood pressures, and those with the lowest LDL-cholesterol levels had a 0.9 year longer lifespan than those with the highest levels. Overall, weight loss seemed to increase lifespan the most, but the level of weight loss required to achieve a 3.9-year increase in longevity may be unrealistic for most people.
“LE [Life expectancy] gained through lower BMI was the largest among the 4 modifiable biomarkers we examined. For people with T2D and a high BMI (the fourth quartile, BMI>36), reducing their BMI to below 25 (the first quartile) was associated with an estimated LE gain of 3.9 years. This benefit, however, might not be easily achieved in clinical practice because it requires a substantial reduction in BMI,” the researchers wrote.
That said, achieving half of the weight loss would still increase lifespan considerably.
“In clinical practice, patients can achieve halfway and gain a proportion of the estimated LE benefit, which is still estimated to be substantial,” they added.
Achieving strict control of HbA1c, blood pressure, LDL-cholesterol and BMI can prevent complications and increase lifespan, but it is crucial that treatment goals are realistic and personalised. The current American Diabetes Association (ADA) and National Institute for Health and Care Excellence (NICE) guidelines suggest tailoring treatment goals to an individual’s age, co-existing conditions, physical and cognitive health status because tight treatment goals can do more harm than good in some individuals. For example, an elderly, frail person with co-existing conditions would benefit from more relaxed treatment goals than a young adult without co-existing conditions.
This study supports the guidelines by showing that a middle-aged male patient with an HbA1c of 8% and blood pressure of 160mmHg could increase his lifespan by 1.4 years by reducing his BMI from 35 to 30, but an elderly patient with the same biomarker characteristics would only increase his lifespan by 0.6 years with the same BMI reduction. In general, younger adults benefit more from improving their biomarkers with tight control than older adults but this control needs to be maintained to retain lifespan benefits.
“The benefit of biomarker control was most pronounced in younger adults and diminishes as people aged…This finding emphasises the importance of biomarker control at an earlier age. It also highlights the potential need for a trade-off between life quality and treatment for elderly patients when the benefit of biomarker control is limited. In addition, our estimation was based on the assumption that goal achievement was maintained for a lifetime. Individuals who met their goal at first but failed to maintain the level of biomarkers had lower benefits from our estimation,” the researchers wrote.
The researchers highlighted several limitations of the study, including being unable to differentiate between participants with type 1 diabetes from those with T2D.
Still, the research showed that “better control of biomarkers can potentially increase the LE by 3 years in an average person with T2D in the US. For individuals with very high levels of HbA1c, SBP [systolic blood pressure], LDL-C and BMI, controlling biomarkers can potentially increase LE by more than ten years.”
“Our findings can be used by clinicians and patients in selecting optimal treatment goals, to motivate patients in achieving them,” they concluded.
Uncontrolled diabetes is associated with a higher risk of cardiovascular disease and complications such as eye and kidney disease. Many studies show that weight loss, blood sugar control and reductions in blood pressure and cholesterol levels can prevent complications and lower cardiovascular disease risk.
This study adds to current knowledge by showing that depending on an individual’s age and medical profile, lowering these risk factors can increase their lifespan by at least three years and, in some cases, more than ten years. Importantly, young adults are the most likely to achieve significant health and longevity benefits, so it is wise for them to aim for strict control as early as possible after diagnosis. Please speak with your health care team to set realistic and achieve treatment goals.