Kuwait Healthy Lifestyle Study: Sleep as a Health Factor

Objective: Kuwait is a country where obesity, metabolic syndrome and type 2 diabetes are highly prevalent health problems.  Sleep duration and quality have been increasingly recognized to be related to weight gain, particularly in children. A longitudinal cohort study is underway to evaluate metabolic status and its correlates in 10,000 ten year old Kuwaiti children.

Methods: Sleep duration and questions about sleep deprivation were collected from 90 10-year old Kuwaiti girls as part of a pilot for the larger study.  Other parameters collected by iPad computers included height, weight, waist circumference, temperature, blood pressure, an oral health exam, a fitness test, and nutrition assessment. In addition, saliva and dental plaque were collected for laboratory analyses. 

Results: The average sleep duration (8.7 hrs) was well within global norms but exhibited wide variation (6 to 12 hrs).  Questions that measured sleep disturbance and daytime dysfunction were significantly related to increased hypertension in these children (p=0.01 to p=0.0007). In addition, reduced sleep was associated with increased sugar consumption, higher prevalence of dental caries and hypertension.  These observations suggest that disrupted and reduced sleep duration may be a risk indicator for both hypertension and caries.  Risk analysis indicated that short sleep duration (≤ 8 hours) was a significant risk factor (OR=3.00, 95%CI=7.68-1.17) for high blood pressure (≥130 mmHg) and approached significance for dental decay (OR=1.94, 95%CI=4.58-0.81). DFT decreased by 0.5 for every additional hour of sleep and approached 0 at 12 hours, while sugar consumption decreased by 14 grams for every hour of sleep.

Conclusion: Sleep dysfunction was significantly related to increased blood pressure, consistent with findings in the literature suggesting that sleep pattern is an important marker of cardiovascular disease. The association between sleep duration and caries is a novel finding which will be further examined in the larger study.