Longevity Briefs: The Diabetes Crisis May Be Worse Than We Thought

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

Diabetes mellitus is a condition in which the body struggles to move glucose (sugar) from the blood into the cells that use and store it. In type I diabetes, this happens because the pancreas does not produce a sufficient amount of insulin, the hormone that activates glucose uptake by cells. In type II diabetes (the most common and preventable type), cells become resistant to insulin, which means they need more of it to produce the same blood sugar lowering effect.

Insulin resistance, diabetes and obesity are closely intertwined with the ageing process and are all part of a wider disruption in how our bodies manage the intake, storage and allocation of energy as we age. Studies show that people with insulin resistance get many age related diseases at a higher rate, including the ‘big three’ (cardiovascular disease, cancer and dementia). And don’t expect medication to completely fix the problem – research suggests that even people whose blood sugar is well controlled by drugs are still at greater risk of cardiovascular disease than those who don’t have diabetes. If we want to combat age-related diseases across the world, prevention of insulin resistance and diabetes is not a bad place to start. Unfortunately, this study just published in the Lancet suggests that the problem is even larger than we thought, and it shows no sign of getting any better.

The discovery:

In the study, researchers analyse a huge dataset from 1108 individual studies with 141 million participants in total. The data includes information on fasting blood sugar, HbA1c (an indicator of blood sugar over time) and diabetes medication. They estimated that the proportion of people living with diabetes at a given age worldwide has doubled in the last 30 years, from around 7% in 1990 to 14% in 2022. Most of that increase happened in low and middle income countries, and while treatment rates mostly kept pace in high-income countries, they fell short elsewhere. They estimate that in 2022, a staggering 445 million adults with diabetes did not receive treatment, which is over triple the number in 1990. In some African countries, treatment coverage was under 10%.

There was also a great variety in diabetes rates among high income countries. The age-adjusted rate of diabetes was 11% for women and 14% for men in the United States in 2022, vs 8% and 10% respectively in the UK and only 2% and 4% in France.

The implications:

Some increase in the number and prevalence of diabetes cases is to be expected, since the global population has not only increased but is also growing older, which means a larger proportion of the population is at higher risk of diabetes. However, this study suggests a large increase in the prevalence of diabetes at a given age, and a greater increase than that which previous studies have suggested. This difference could be due to the fact that the study used HbA1c as well as fasting glucose to assess diabetes, capturing a wider range of cases. They also did not rely on self-reported diabetes like some studies, which underestimates prevalence since it misses undiagnosed cases.

So, why are diabetes rates so high? Lifestyle factors are to blame, with obesity and diet leading to a large proportion of diabetes cases. High calorie processed foods are cheap and often minimally regulated in low and middle-income countries. Interestingly, the few groups in which obesity rates have decreased or remained stable since 1990 (such as Japanese women) actually experienced a decline in diabetes rates at a given age. An increase in the number of people living sedentary lifestyles is also likely to carry some of the blame.

What can be done about these problems? It is easy to place the blame on individuals for making poor lifestyle choices, but human nature hasn’t radically changed in the recent past. There was no obesity epidemic 100 years ago – our environment clearly caused this crisis, so to fix it we’re going to need to address that environment through regulation, or resign ourselves to medicating over a tenth of the human race.