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Which illnesses could be an early sign of diabetes?

A doctor listens to a patient's lungs via a stethoscope through their back
Respiratory illnesses may be a precursor of later-onset type 2 diabetes. Jahi Chikwendiu/The Washington Post via Getty Images
  • Type 2 diabetes commonly develops concurrently with other serious conditions, including cardiovascular and pulmonary disorders.
  • Researchers in the United Kingdom surveyed the trajectory of such illnesses in people with and without type 2 diabetes for up to 50 years.
  • In years preceding a type 2 diabetes diagnosis, the individuals who developed type 2 diabetes had a greater tendency to develop hypertension, kidney and respiratory problems, and infections.

Type 2 diabetes is a chronic disorder marked by high blood glucose levels. This could be due either to insufficient insulin levels, insulin resistance, or both factors.

Research shared at the 2023 Annual Meeting of The European Association for the Study of Diabetes in Hamburg, Germany suggests that it might be easier to track early type 2 diabetes development in some individuals.

The insights, also published in Diabetes Therapy, came from an analysis based on data from the Diabetes Alliance for Research in England (DARE) study.

Study first author Dr. Adrian Heald of Manchester University, United Kingdom said in a press release: “These findings hint at the potential for type 2 diabetes to be diagnosed earlier, and we hope that the distinct clinical trajectory could become a predictive tool for people at risk of the disease.”

Discovering the natural course of type 2 diabetes

Type 2 diabetes often develops alongside other conditions. The present study sifted through pre- and post-type 2 diabetes diagnosis clinical histories for further insights into causes and trajectories for related health conditions.

Dr. Heald and his team said “[t]he main goal of this study was to detect any temporal continuums of comorbidity or clinical indications which predate the onset of diabetes and to document the important health difficulties in persons on a time continuum spanning from before and after a clinical diagnosis of type 2 diabetes.”

The researchers say that the set of causes behind type 2 diabetes are yet undetermined, but onset is “clearly linked to chronic overweight and obesity and a sedentary lifestyle.”

The causal link associations between type 2 diabetes and multimorbidity — several coexisting health conditions — remain unknown as well.

Previous studies suggest that environmental variables, including lack of physical activity and access to healthy foods, may promote the disease’s emergence.

Several common illnesses that may indicate diabetes

The U.K. researchers turned to the DARE study to find the most prevalent clinical conditions in people with type 2 diabetes.

They searched through data on 1,932 adults with and without type 2 diabetes, matched by age and gender, over a period covering 50 years – 25 years pre-diagnosis and 25 years post-diagnosis.

The researchers reviewed health records on 1,196 people who eventually received a type 2 diabetes diagnosis and 736 who did not. The average age at diagnosis was 53 years.

The analysis revealed that several common illnesses increased consistently in the years preceding diagnosis. These included hypertension, respiratory tract infections, cardiovascular conditions, asthma, and eye, nose, and throat infections.

The study authors saw that immediately prior to being diagnosed with type 2 diabetes, over one in three people had high blood pressure and respiratory tract infections. Approximately one in five experienced a heart condition or eye, nose, and throat infection, and one in 10 had asthma.

On the other hand, only one in 20 people who did not develop type 2 diabetes were diagnosed with these illnesses. Respiratory tract infections followed a different trajectory, being experienced by one in 10 of these individuals.

Inflammation may be a precursor to type 2 diabetes

After a type 2 diabetes diagnosis, cases of hypertension, chronic kidney disease (CKD), retinopathy, and infections spiked for 15 years before leveling off. Heart conditions and asthma followed this course as well.

The U.K. researchers believe this suggests that subacute inflammation, caused by genetics or comorbidities, “may serve as a precursor to the later onset of [type 2 diabetes].”

The study’s findings may also indicate that type 2 diabetes is not necessarily inevitable.

“Understanding the long-term clinical history of type 2 diabetes years before diagnosis means that, in the future, people could have the time to make lifestyle changes to prevent this life-changing disease from arising,” Dr. Heald said.

Why people with diabetes may have other illnesses

Dr. Heald and his team noted that several illnesses tend to co-occur with type 2 diabetes.

Health experts treat hypertension as a risk factor due to its increasing frequency among individuals with other factors, such as obesity and smoking.

Asthma Trusted Source PubMed Central Highly respected database from the National Institutes of Health Go to source and other inflammation issues, while not widely recognized, appear to be risk factors as well.

Research confirms that chronically elevated blood glucose levels can damage the vascular endothelium and other tissues. This can lead to increased insulin resistance and risk of heart disease.

Medical News Today discussed the present study with Dr. Jagdish Khubchandani, a professor of public health at New Mexico State University, who was not involved in this research.

Dr. Khubchandani agreed that chronic conditions do not just happen in isolation, saying: “Given the volume of evidence on the co-occurrence of these conditions, the findings are not coincidental but more of a syndrome complex.”

“Once a person acquires one chronic disease, the likelihood for the occurrence of other chronic conditions increases substantially via multiple pathways. These can be immune, inflammatory, biochemical, or psychological, among the many unknowns.”
— Dr. Jagdish Khubchandani

“For example, individuals with chronic respiratory illness may have immune dysregulation or chronic inflammation, which may lead to insulin resistance and the development of diabetes. Or, the medications taken to treat chronic respiratory conditions may affect metabolism and lead to diabetes,“ Dr. Khubchandani further explained.

“Also, oftentimes, individuals with chronic diseases have more stress or are prone to depression and anxiety that are also linked to diabetes — links via unhealthy dietary patterns, poor weight management, etc.,” he added.

How type 2 diabetes is linked to social inequalities

In their paper, the U.K. team also cited a 2021 study demonstrating a link between social inequities and “adverse cardiac outcomes” in individuals with type 2 diabetes.

The experts remarked that “[m]easures that reduce social inequality have the potential — in the longer term — to reduce the social gradient in health outcomes described here.”

Dr. Khubchandani saw social factors as “one of the major pathways connecting chronic respiratory illness to diabetes or for the risk of developing [type 2 diabetes] alone”.

He said that people from historically marginalized groups and those with lower financial and educational resources are more likely to experience chronic respiratory illnesses. Their tendency not to get quality treatment can create a “greater psychosocial burden”, which can increase the risk of type 2 diabetes.

“Belonging to a lower income and education group also affects living conditions, knowledge of health-related issues, access to healthy food, and ability to engage in the recommended amounts of physical activity. These can individually be linked to type 2 diabetes without having other chronic conditions. One can assess these from rates of type 2 diabetes in the rural and Southern U.S. where multiple such disadvantages affect individuals.”
— Dr. Jagdish Khubchandani

Study limitations

The research team behind this study admits that their sample size was small. However, they hope to extend the study in due time. The analysis also depends on the accuracy of primary care coding data, which could contain errors.

Dr. Heald and his cohort expect that larger population studies, artificial intelligence, and machine learning analytics will help “address […] [the] multifactorial complexity” of interpreting health records for disease patterns.

Type 2 diabetes has multiple subgroups, all of which the researchers could not examine in this study. Moreover, the actual year of type 2 diabetes diagnosis could be several years after the onset of symptoms since early hyperglycemia can be asymptomatic.

This article originally appeared on Medical News Today.

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