Researchers at Weill Cornell Medicine – Qatar (WCM-Q) have shown that lack of sleep is likely to be a contributing factor in childhood obesity in Qatar.

The relationship between obesity and insufficient sleep has been demonstrated before, but the majority of studies have relied on subjective estimates of sleep, and only one indicator of obesity. By contrast, the team from WCM-Q used five indicators of obesity to ensure the condition was accurately defined. They also issued each subject with a wrist actigraphy device which records movement and allows researchers to accurately and objectively estimate sleep parameters.

Sleep and Obesity

The study was conducted on 335 elementary schoolchildren in Qatar aged between seven and 12 years old. Each child was asked to wear the actigraph for seven consecutive days and nights. The children had their neck and waist circumferences measured, their height and weight taken, allowing their body mass index (BMI) to be calculated, and their percentage of body fat and fat mass measured.

The research found that the average time at which the children went to sleep during the week was 9:22 pm, and the average time at which they woke was 6:26 am.

Of the sample, 42.1% were classified as either overweight or obese based on the variables set by the World Health Organisation (WHO). Of those children, weekday sleep duration was significantly shorter at 7 hours and 36 minutes, as opposed to 7 hours and 54 minutes for those who were a healthy weight.

Although sleep is certainly not the only factor involved in obesity, the researchers state that it appears to be a contributory factor. Sleep duration may influence food intake, food selection, and energy expenditure with downstream effects on body fat.

Dr Shahrad Taheri, Director of the Clinical Research Core and Assistant Dean for Clinical Investigations, said that the body of evidence pointed to lack of sleep as affecting a person’s weight. There is an increasing evidence supporting this study on both children and adults.

The study demonstrates that conditions like obesity are far more complex than we first thought, and should be treated holistically.’

Qatar, according to Dr Taheri, has a high prevalence of obesity and there is a need to look at improving sleep to prevent and tackle obesity. He said that they plan to undertake further research to see if it’s possible to reduce obesity through a lifestyle change and modifications in diet, physical activity and sleep.

For more information about researches and studies conducted and initiated by WCM-Q, visit their website at qatar-weill.cornell.edu.