Association between sleep duration and haemoglobin A1c in young adults.

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.