The association between low-carbohydrate diet score and sleep duration among Iranian adults

Sleep disorders are linked to obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). The evidence suggests that dietary carbohydrate content may be related to sleep duration. We designed a study to investigate the association between a low-carbohydrate diet (LCD) with long sleep duration (> 8 h) and short sleep duration (< 5 h). This cross-sectional analysis was conducted on data obtained from the recruitment phase of Yazd Health Study (YaHS) and the Taghzieh Mardom-e-YaZd (TAMYZ). The dietary intake was assessed using a validated food frequency questionnaire. The LCD score was calculated for each subject based on summing up assigned scores to deciles of percentages of energy from macronutrients. Sleep duration was assessed using a nocturnal sleep questionnaire. The association between LCD and sleep duration was evaluated using logistic regressions in crude and adjusted models. A total of 5929 subjects were entered into the analysis. Most of the participants were aged 20-29 years (24.8%), male (52.2%) and never smokers (87.7%). After adjusting for level of physical activity, age, sex, total energy, smoking status and body mass index in model III, a significant direct association was observed between LCD score with long sleep duration (OR 1.15; 95% CI1-1.32, P = 0.049) and short sleep duration (OR 1.29; 95% CI 1.02-1.62, P = 0.028). Higher LCD score is associated with higher chance of long sleep duration and short sleep duration. Regarding the nature of our study, cohort and clinical trial studies in future are required to reach a causal association and a definitive conclusion.