A recent study detected a marked increase in several common conditions in the years running up to and right before someone being diagnosed with type 2 diabetes.
These study results suggest that diagnosis could be made considerably earlier in some individuals.
The research was presented at this year’s EASD meeting which was held in Hamburg in Germany.
Senior author Dr Adrian Heald, from Manchester University and Salford Royal Hospital, said: “These novel insights into the onset and natural progression of type 2 diabetes, suggest an early phase of inflammation-related disease activity long before any clinical diagnosis of type 2 diabetes is made.
“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.”
Type 2 diabetes is linked to a wide and continually growing number of illnesses and related treatments.
There has been progress in pinpointing genetic and non-genetic factors that increase the risk of developing type 2 diabetes, however, further research into the clinical history of individuals before and after diagnosis could help identify its causes and the trajectory of various health conditions.
The researchers from Manchester Metropolitan University, Manchester University and Salford Royal Hospital explained: “In this study, we utilised longitudinal data from the DARE (Diabetes Alliance for Research in England) study to examine the trajectory of clinical conditions in individuals with and without type 2 diabetes.
“Data from 1,932 individuals (type 2 diabetes n = 1,196 vs. matched non-type 2 diabetes controls n = 736) were extracted and subjected to trajectory analysis over a period of up to 50 years (25 years pre-diagnosis/25 years post-diagnosis). We also analysed the cumulative proportion of people with diagnosed coronary artery disease (CAD) in their general practice (GP) record with an analysis of lower respiratory tract infection (RTI) as a comparator group.”
In people who are ultimately diagnosed with type 2 diabetes, the study pinpointed numerous common conditions that appear frequently in the years leading up to diagnosis.
These conditions include eye, nose, and throat infections, high blood pressure, respiratory tract infections, heart conditions and asthma.
Results demonstrate that right before diagnosis, more than one in three people had high blood pressure and a respiratory tract infection, approximately one in five had a heart condition or eye, nose, and throat infection, and one in 10 developed asthma.
The data for people who were not diagnosed with type 2 diabetes showed that less than one in 20 were diagnosed with any of the same conditions, however approximately one in 10 experienced respiratory tract infections.
Following a type 2 diabetes diagnosis, the number of people exhibiting, chronic kidney disease, retinopathy and infections increased quickly for approximately 15 years and then plateaued.
Cases of heart conditions and asthma also continued to rise in people following a type 2 diabetes diagnosis.
Dr Heald explained: “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 lifechanging disease from arising.
“This study demonstrates that subacute inflammation which manifests as the onset of hypertension, asthma or an acute infection, regardless of whether it is caused by the genome, demography or comorbidities, may serve as a precursor to the later onset of type 2 diabetes.”
He added: “These observations offer a fascinating and fresh perspective on the beginning and normal development from pre-type 2 diabetes to type 2 diabetes diagnosis and beyond, implying a possible early stage of disease activity that is linked to, but not yet clinically diagnosed as, diabetes.
“The matter of metabolic control and how this relates to a broad range of treatment factors (pharmacological and non-pharmacological) will be addressed in a future work.”
Although the findings are significant, it is important to note the small size of the retrospective observational study so it cannot prove causation and that unmeasured factors possibly influenced the results.
The researchers said: “In relation to sample size, we accept that the sample size is small. Given the wide geographical spread of the DARE study and the duration of the follow-up that has been enabled through active ethical permission, we anticipate being able to extend the study to much larger numbers in due course.”
Other limitations acknowledged by the researchers that may have affected the study results include the analysis depending on the accuracy of the coding at the level of GP which could involve some bias, type 2 diabetes being a diverse disorder so not all possible subgroups were examined and some multimorbidity could have been linked to socio-economic deprivation.
The study was published in the journal Diabetes Therapy.