Number Of People Living With Type 1 Diabetes Predicted To Double Worldwide By 2040: Study In Lancet

As many as 3,16,000 adolescents were estimated to be suffering from type 1 diabetes in 2021. Meanwhile, the estimated number of children living with type 1 diabetes in 2021 was 1,94,000.

About 8.4 million people worldwide were estimated to be living with type 1 diabetes worldwide in 2021. The number is predicted to double by 2040, a new study published in The Lancet Diabetes & Endocrinology reports. In other words, 13.5 to 17.4 million are predicted to live with type 1 diabetes, in less than 20 years, the study states. Type 1 diabetes is historically thought of as a disease with onset in childhood. However, in 2021, it was estimated that there were numerically more adults diagnosed with type 1 diabetes than children and adolescents. 

As many as 3,16,000 adolescents were estimated to be suffering from type 1 diabetes in 2021. Meanwhile, the estimated number of children living with type 1 diabetes in 2021 was 1,94,000.

What Is Type 1 Diabetes?

Diabetes is of two types: diabetes mellitus and diabetes insipidus. In diabetes mellitus, the level of glucose in the blood is too high, as a result of which the kidneys try to remove the extra glucose by passing it in the urine. Meanwhile, in diabetes insipidus, the blood glucose levels are normal, but the kidneys cannot properly concentrate urine. 

Diabetes mellitus is classified into three categories, namely, type 1 diabetes, type 2 diabetes, and gestational diabetes. 

Type 1 diabetes, earlier known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin, a hormone which helps blood sugar enter the cells in the body for use as energy. Without insulin, glucose cannot enter the cells and builds up the bloodstream, as a result of which the person suffers from different symptoms and complications of diabetes.

How Were The Estimates Made?

The researchers made the estimates on type 1 diabetes prevalence, associated mortality, and life expectancy in all countries using a model known as Markov model. It is a model which forecasts the value of a variable, whose predicted value is dependent only on the current state, and is independent of anything that happened in the past. 

Disease incidence measures the rate of occurrence of new cases of a particular disease or condition in a specified time, while disease prevalence is measure of the number of individuals with a particular disease or condition at a single point of time. Prevalence includes both new and pre-existing cases, while incidence includes only new cases. 

Using this model, the researchers predicted the number of people who will be living with type 1 diabetes by 2040.

Data on type 1 diabetes incidence and mortality were available from 97 and 37 countries, respectively. 

In order to predict type 1 diabetes incidence, prevalence, and mortality in 2021 for 201 countries, and the future prevalence through 2040, the researchers modelled data on childhood, adolescent and adult type 1 diabetes prevalence in 97 countries, the data on incidence of type 1 diabetes over time from 65 countries, and mortality data from 37 countries. 

In order to see if their estimates were accurate, the researchers compared their data with real-world prevalence data from 15 countries. 

How Will The Study Data Be Useful To The World?

In a statement released by The Lancet, Professor Graham Ogle, one of the authors on the paper, said the prevalence of type 1 diabetes in all countries is projected to increase up to 17.5 million in 2040. He stated that the study results provide a warning for substantial negative implications for societies and healthcare systems. 

Ogle suggested that by raising the standard care for type 1 diabetes and increasing awareness of the signs and symptoms of the condition, millions of lives can be saved. Steps such as ensuring universal access to insulin and other important supplies will enable a 100 per cent diagnosis of type 1 diabetes in all countries. 

Ogle explained that the model used in the study will make data on the burden of type 1 diabetes widely accessible. Also, stakeholders can use the data to make improvements in type 1 diabetes care and outcomes, he said.

Lack Of Data On Type 1 Diabetes Prevalence In Adults

For most countries, data on type 1 diabetes prevalence and mortality is rarely available. This is because not much data is available on the prevalence of diabetes and associated mortality in low- and middle-income countries, and in adult populations, the study states.

Most precious studies calculated type 1 diabetes incidence using European and North American data. 

A study titled 'Diabetes in sub-Saharan Africa: from clinical care to health Policy' was published in The Lancet Diabetes & Endocrinology in 2017. The study said that the number of people with diabetes in sub-Saharan Africa has increased very rapidly in the past three decades, and called for an urgent need for worldwide data on type 1 diabetes. 

New Study Estimates Missing Prevalence Of Type 1 Diabetes For The First Time

The new study aims to answer these calls, and provides model estimates that are highly comparable to observed data. The study also estimates missing prevalence for the first time, and provides a more meaningful basis for change in type 1 diabetes care and policy. 

Important Findings

The model estimates that 8.4 million individuals worldwide were living with type 1 diabetes in 2021. Of these, 1.5 million people were younger than 20 years of age. This means that 18 per cent of the people estimated to be living with type 1 diabetes in 2021 were aged less than 20 years. 

As many as 5.4 million were aged 20 to 59 years, accounting for 64 per cent of the total number of people estimated to be living with the condition in 2021. 

The number of people aged 60 years or above was 1.6 million. They accounted for 19 per cent of the estimated number of people. 

As many as 0.5 million new cases of type 1 diabetes were diagnosed in 2021. For these people, the median age of onset of type 1 diabetes was 39 years. About 35,000 non-diagnosed individuals died within 12 months of symptomatic onset of type 1 diabetes, the authors note in the study. 

About 1.8 million individuals from low-income and lower-middle-income countries were living with type 1 diabetes in 2021. 

In low-income countries, the remaining life expectancy of a 10-year-old with type 1 diabetes in 2021 was 13 years. In high-income countries, the remaining life expectancy of a 10-year-old with the condition in 2021 was 65 years. 

More Adults Than Children Diagnosed With Type 1 Diabetes Annually

Since 3,16,000 adults were estimated to be living with type 1 diabetes in 2021, compared to 1,94,000 children and adults in the same year, the study states numerically more adults than children are diagnosed every year. The mean diagnosis age for type 1 diabetes is 32 years. 

3.7 Million Missing Prevalent Cases In 2021

The researchers estimated that there were 3.7 million missing prevalent cases in 2021. This means that there existed no data on the prevalence of about 3.7 million cases of type 1 diabetes in 2021. 

Countries With Highest Estimated Type 1 Diabetes In 2021

According to the study, the ten countries with the highest estimated type 1 diabetes prevalence in 2021 are the United States, the United Kingdom, India, China, Russia, Brazil, Germany, Canada, Spain, and Saudi Arabia. The countries account for 60 per cent of the global cases of type 1 diabetes. This means that the total number of people from these countries estimated to be living with type 1 diabetes in 2021 is 5.08 million. 

How Many Global Deaths From Type 1 Diabetes Are Predicted To Have Occurred In 2021? 

In 2021, the number of global deaths occurring due to type 1 diabetes was 1,75,000, the model predicts. Of these, 35,000 deaths occurred due to non-diagnosis. 

Of these, 14,500 people were in sub-Saharan Africa, and 8,700 were in South Asia. 

An additional 3.1 million people would have been alive in 2021 if they had not died prematurely due to suboptimal care of type 1 diabetes, the researchers estimate. 

What Do The Authors Interpret?

The researchers note that a further 700,000 people would still be alive if they had not died prematurely due to non-diagnosis of type 1 diabetes. 

The authors predict an increase in prevalent cases to 13.5 to 17.4 million in 2040. This is 60 to 107 per cent higher than in 2021. 

The largest relative increase with respect to the number of cases in 2021 is predicted to take place in low-income and lower-middle-income countries, the authors conclude.

Therefore, the study highlights that the burden of type 1 diabetes in 2021 is vast, and is expected to increase rapidly, especially in resource-limited countries. The researchers note that most incident cases and prevalent cases are adults. 

There is a need to raise awareness about the premature mortality of type 1 diabetes, and raise the standard of care for the condition, the authors suggest.