Short Sleep Duration as a Risk Factor for Obesity and Gingivitis in Kuwaiti Children: A Longitudinal Multilevel Analysis

Objectives: It has been shown that inadequate sleep has negative effect on health including obesity, diabetes, and cardiovascular diseases. Current evidence showed that little sleep impairs immunity, promotes systemic inflammation, and increases the risk of pathological change in many body organs. Aims of this study were to assess the relations between insufficient sleep in developing obesity and gingivitis among a cohort of Kuwaiti children. We also identified the risk behaviors contributed to decreased sleep among those children. This is the first study that has examined the relation between sleep duration and the oral inflammatory condition; gingivitis. In addition, the majority of research related to sleep has been conducted in western countries. Therefore, it seems logical to examine sleep duration as a risk factor for obesity in a population having one of the highest adult prevalence levels of obesity in the world; the Kuwaiti population. Methods: Longitudinal data were collected from 6,316 children 8-14 years old at two time points. Children were approximately equally distributed from 138 elementary schools and representing the 6 governorates of Kuwait. Calibrated examiners in the selected schools conducted oral examinations, sleep evaluation interviews, body weight measurements, nutritional analysis, physical activity assessments, and collected saliva samples. A cross sectional model, and four longitudinal multilevel models were conducted to determine four different outcomes; waist circumference, obesity, gingivitis, and sleep duration at three levels; time, individual, and school. The main independent variables examined were daily sleep hours and salivary glucose levels. Other explanatory variables and confounders assessed were: dental caries, tooth filling, trouble breathing at night, TV and videogame use, and governorate; adjusted for snacking and gender. Results: There was a statistically significant increase in abdominal obesity and gingivitis with shorter sleep duration with significant change over time (P<0.05). Children who watched TV or played videogames just before bedtime, and those who used screen activities more than two hours a day, slept significantly less than other children. The magnitude of gingivitis was significantly different between the six governorates of Kuwait (P<0.05). There was a statistically significant variation in the observations between schools over time. Conclusion: Longitudinal analysis of Kuwaiti children revealed that obesity and gingivitis increased with shorter sleep duration overtime. Screen based activities including TV and videogame use were major factors contributed to decrease night sleep hours. There was a strong clustering effect within the schools in shaping the three health conditions; obesity, gingivitis, and short sleep duration in Kuwaiti children. Public health intervention programs should target children and their families in schools at higher risk to focus on improving night sleep behavior as well as limit their screen time, in addition to maintaining healthy eating habits, practicing proper oral hygiene measures, and being physically active. Supporting agency and grant number: The Dasman Institute in Kuwait funded this study. The Grant number is: (RA/065/2011 and RA/005/2011).