Faster rise in glucose during adolescence tied to higher levels as adult
Study follows abnormal glucose tolerance (AGT) levels in CF patients
Cystic fibrosis (CF) patients who had fasting blood sugar (glucose) levels that rose more quickly throughout adolescence were more than three times as likely to have abnormal glucose tolerance (AGT) in early adulthood than their peers whose levels rose more slowly, a study found.
AGT refers to elevated or borderline elevated blood glucose levels, and can include patients with CF-related diabetes (CFRD).
As noted by the authors, the study data indicate these fasting glucose trajectories “could help identify children more likely to develop an AGT early after the transition to adult care,” although more studies are needed.
The study, “Latent class analysis to identify childhood predictors of abnormal glycemic status in young adults with cystic fibrosis,” was published in the journal Diabetes Epidemiology and Management.
Many CF patients exhibit signs of AGT, or higher-than-normal blood sugar. When insufficiently controlled, this can lead to CFRD, a condition associated with other negative outcomes, including worse lung function and higher mortality rates in adulthood.
It has not been well-established whether there are certain clinical features in childhood that may predict an AGT or CFRD status later on in adulthood for CF patients.
“Early recognition of the risk markers and clinical deterioration associated with this comorbidity [co-existing condition] is imperative to target patients at risk, optimize their medical care and improve long-term outcomes,” the authors wrote.
In the study, researchers examined long-term health data from 108 CF patients in Canada in an effort to identify risk factors for AGT.
Pediatric records from these patients were obtained from the Centre Hospitalier Universitaire Sainte-Justine in Montreal where they were followed as children, and then matched to their adult records from the Montreal Cystic Fibrosis Cohort after they had transitioned to adult care.
Of these 108 patients, 38 had normal glucose tolerance during their first available test after transitioning to adult care, and 70 were classified as having some type of AGT.
AGT status was determined with an oral glucose tolerance test, which measures blood glucose after fasting, and again in the two hours after a patient consumes a sugary drink.
Different trajectories
The team then identified different trajectories for the children based on CF-associated clinical features, and examined which trajectories were most likely associated with AGT in early adulthood.
Initial statistical analyses found that children with two copies of the F508del mutation — the most common CF-causing mutation — were more likely to develop AGT later in life than children with only one copy.
Moreover, children with pancreatic insufficiency — when the pancreas doesn’t make enough of the enzymes needed for digestion — were more likely to have altered glucose tolerance.
Fasting glycemia, a blood sugar measurement taken after a period of not eating or drinking, also was linked to AGT.
Children with higher fasting blood sugar at age 10 — albeit still within a normal range — that rose rapidly until age 18 and reached abnormal levels, were more likely to have AGT in adulthood compared with children who had lower fasting glucose that rose more gradually.
Notably, other measures of blood sugar in childhood were not significantly linked to later AGT status. Other clinical factors such as lung function and body mass index also were not linked to AGT in adulthood.
A significant predictor
In final analyses, only fasting glycemia measurements were found to be significant predictors of AGT status, with children who had higher and rapidly progressing fasting glucose at a more than three times greater risk of developing AGT later in life.
That finding highlights “the utility of monitoring fasting glycemia values over time during childhood,” the researchers wrote, rather than relying on a single blood sugar test to predict AGT later.
The researchers noted their study was limited by the fact that AGT status in adulthood was determined with only a single test, and did not account for potential fluctuations that some patients may experience.
“Future studies should address whether the trajectories of patients with fluctuating statuses differ from those with stable glucose tolerance,” the researchers wrote.
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