Sleep Duration and Diabetes Risk in American Indian and Alaska Native Participants of a Lifestyle Intervention Project

Study Objectives: We examine the association between self-reported sleep duration and diabetes incidence in a national sample of American Indians/Alaska Natives (AI/ANs) with prediabetes. Methods: Data were derived from the Special Diabetes Program for Indians Diabetes Prevention demonstration project. This longitudinal analysis included 1,899 participants with prediabetes recruited between January 1, 2006 and July 31, 2009 who reported sleep duration and completed all 16 classes of the lifestyle intervention consisting of diet, exercise, and behavior modification sessions to promote weight loss. Three years of follow-up data were included to fit Cox regression models to compute hazard ratios (HRs) for diabetes incidence across sleep duration categories. Results: The crude diabetes incidence rate was 4.6 per 100 person-years among short sleepers (<= 6 h per night) compared to 3.2 among those sleeping 7 h and 3.3 among those sleeping 8 h or more. After adjustment for age and sex, short sleep (<= 6 h vs. others) was associated with increased diabetes risk (HR 1.55 [95% confidence interval 1.11-2.17]); risk remained significantly elevated after controlling for socioeconomic characteristics, health behaviors, and health status. When adjusting for body mass index and percent weight loss, the short sleep-diabetes relationship was attenuated (HR 1.32 [95% confidence interval 0.92-1.89]). No significant long sleep-diabetes association was found. Further, short sleepers lost significantly less weight than others (3.7% vs. 4.3%, P = 0.003). Conclusions: Short sleep duration, but not long duration, was significantly associated with increased diabetes risk and less weight loss among AI/ANs in a lifestyle intervention. Further exploration of the complex factors underlying short sleep duration is warranted.