medwireNews: Impaired glucose tolerance in obese youths frequently reverts to normal, although the chances of this happening are strongly influenced by ethnicity, researchers report in The Lancet Child & Adolescent Health.
However, reverting to normal glucose tolerance was associated with a significant increase in the oral disposition index, used as a surrogate of beta-cell function, from a median of 0.94 at baseline to 3.90 after a median 2.9 years of follow-up.
In a linked commentary, Soon Song (Northern General Hospital, Sheffield, UK) raises the question of whether this reversion to normal glucose tolerance is sustainable in the long term, pointing out that the resolution of impaired tolerance “was achieved with increased β-cell workload, which could ultimately lead to failure.”
He adds: “Longer follow-up of this cohort is needed to answer this question.”
The cohort comprised 526 adolescents, aged between 10.6 and 14.2 years, who attended the Yale Pediatric Obesity Clinic. All had a BMI greater than the 85th percentile for their age and sex, and 31% had impaired glucose tolerance.
During follow-up, 65% of these children reverted to having normal glucose tolerance, 27% had persistent impaired tolerance and 8% progressed to type 2 diabetes. Of the children with normal glucose tolerance at baseline, 14% became glucose intolerant. The oral disposition index declined in these children, as it also did in those with persistent impaired glucose tolerance and those who developed type 2 diabetes.
Non-Hispanic White children were fivefold more likely than non-Hispanic Black children to revert to normal glucose tolerance, after accounting for factors including family history of type 2 diabetes, pubertal stage and change in BMI over time.
In line with this, the oral disposition index rose by an annual median of 189% in non-Hispanic White children with baseline impaired glucose tolerance, compared with 83% in non-Hispanic Black children, report Sonia Caprio (Yale University School of Medicine, New Haven, Connecticut, USA) and co-researchers.
The ethnic differences in beta-cell function only occurred among children who progressed, however, with no differences found at baseline or among children who maintained normal glucose tolerance.
In his commentary, Song says the finding “that impaired glucose tolerance can be a transient and highly reversible condition in obese youths offers optimism and further encouragement to prevent diabetes in these young people.”
However, he highlights the concerning “decline in β-cell function within a short period in a substantial proportion of obese youths despite their young age.”
Song says the findings complement the recent RISE Consortium findings, which showed that obese glucose-intolerant children are “susceptible to accelerated β-cell failure with more rapid progression to type 2 diabetes compared with adults.”
He concludes: “Effective management of prediabetes is crucial to prevent progression to type 2 diabetes and its associated complications. Strategies for intervention should take into consideration the highly reversible nature of youth prediabetes and its ethnic predisposition.”
By Eleanor McDermid
Lancet Child Adolesc Health 2018; doi:10.1016/S2352-4642(18)30235-9
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