Type 1 Diabetes May Not Impair School Performance in Kids

Miriam E. Tucker

February 05, 2019

Having type 1 diabetes per se may not affect school performance among children but glycemic control could, a Danish study suggests.

"In this population-based cohort study, there was no statistically significant difference in pooled reading and math test scores between children with and without diabetes," note Niels Skipper, PhD, of the Department of Economics and Business Economics, Aarhus University, Denmark, and colleagues, in their article published online February 5 in JAMA.

The study involved more than 600,000 Danish schoolchildren and compared 2000 kids with type 1 diabetes to those without. Even after adjusting for socioeconomic status, there were no significant differences overall in standardized test scores between the groups.

However, among the children with diabetes, those with lower HbA1c levels performed better on the tests. And interestingly, children with HbA1c levels below 7.5% actually scored slightly better than those without diabetes. 

These findings conflict with some previous studies that found poorer academic performance among children with type 1 diabetes compared to those without. The difference may be because of improvements in diabetes care in recent years, Skipper and colleagues suggest, noting that two thirds of the children in the current study population were using insulin pumps.

"It is possible that advances in treatment modalities over recent decades...have improved not only gaps in mortality and morbidity between individuals with diabetes and the overall population but also have improved gaps in school performance," they write.

Reading, Math Scores Not Significantly Different

The study population included a total of 631,620 children in grades 2 through 8 at public schools in Denmark (where standardized testing is mandatory), including 2031 with type 1 diabetes.

Reading tests were given in grades 2, 4, 6, and 8, and math tests in grades 3 and 6.

Among the children with diabetes, mean duration was 4.5 years, 18% had diabetic ketoacidosis (DKA) at onset, and 64.0% used insulin pumps.

Mean test scores, on a scale of 1-100, were 56.56 for those with diabetes and 56.11 for those without. The difference, 0.24 points, was not significant. And even after adjustment for socioeconomic status, the 0.45-point difference still didn't reach statistical significance. 

Test Scores Linked to HbA1c

The 1155 children with HbA1c levels greater than 7.5% had significantly lower test scores than those without diabetes (53.84 vs 56.11; difference –2.26) but the difference was no longer significant after adjustment for socioeconomic status (difference –1.06).

But among those with HbA1c greater than 8.6%, test scores were significantly lower compared to those without diabetes even after adjustment (difference –2.47).      

Having DKA at diabetes onset and onset at younger than 6 years weren't associated with significant test score differences compared to children without diabetes.  

And of note, children with HbA1c levels less than 7.5% scored slightly above the average for the entire population.  

Overall, test scores were 3.48-points lower for each 1% increase in HbA1c, and were 1.59-points lower after adjustment for socioeconomic status.

Skipper and colleagues offer two possible explanations for the higher test scores among those achieving HbA1c levels less than 7.5% compared with the rest of the population.

"One interpretation could be that the parents of children with type 1 diabetes direct more of their resources toward the affected child, giving rise to both better school performance and better metabolic control."

Or, they theorize, "being able to maintain good glycemic control and school performance is confounded by ability (cognitive and noncognitive skills), which is correlated with socioeconomic status."

The authors caution about extrapolating the findings. "Denmark has considerable diabetes awareness and good medical and social care by international standards, and hence the findings may not apply to other countries. It is possible that the gaps in test performance are larger in countries where access to healthcare is associated with socioeconomic status."

The study was funded by an Independent Research Fund Denmark grant. Skipper has reported no relevant financial relationships. Disclosures for the other authors are listed in the article.

JAMA. Published online February 5, 2019. Abstract

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