Background Epidemiological and experimental evidence suggests that inadequate sleep can cause both obesity and impaired glucose tolerance. Short sleep duration in childhood appears to have a greater impact on the risk for adult obesity than adult sleep duration. The long-term effects of childhood sleep on glucose metabolism have not been investigated. The authors assessed the associations between childhood and adult sleep duration and adult glycosylated haemoglobin (HbA_1c) levels.

Methods An unselected cohort of 1037 individuals, born in Dunedin, New Zealand, between 1972 and 1973. Parent reports of times in bed at ages 5, 7, 9 and 11 were used to estimate childhood sleep duration. Adult sleep duration was estimated from self-reported times in bed at age 32. HbA_1c levels were measured at age 32. Pregnant women and participants with diabetes were excluded from the analyses.

Results Childhood sleep duration did not predict adult HbA_1c. However, less time spent in bed at age 32 was associated with higher levels of HbA_1c (p=0.002) and an increased risk of prediabetes (p=0.015). The inverse association between adult sleep times and HbA_1c was independent of body mass index, smoking, socioeconomic status, shift work and symptoms of obstructive sleep apnoea.

Conclusions Short sleep duration is associated with higher levels of HbA_1c and an increased risk of prediabetes in young adults. The findings suggest that inadequate sleep impairs glucose control in the short term and may increase the risk for long-term health problems.