Poor sleep, physical inactivity up risk of obesity

Obesity is a disease characterised by excessive body fat. People, who are medically obese, usually are affected by behaviour, genetic and environmental factors that are difficult to control with dieting.

India has the second highest number of obese children in the world after China - with 14.4 million children having excess weight.

Globally, over two billion children and adults suffer from health problems related to being overweight or obese, and an increasing percentage of people die from these health conditions.

There are lots of factors that can cause obesity, but a group of scientists have found a reason which can actually worsen the risk factors for obesity.

Poor sleep and low levels of physical activity worsen the impact of risk factors for obesity, according to recent study.

According to researchers, it was difficult earlier to measure interactions between genetic risk factors and aspects of environment and lifestyle in a systematic way.

Dr. Timothy Frayling, Ph.D., Professor, shared that during their earlier researches, they were not able to measure physical activity and sleep patterns with as much precision as genetic variants as they relied on diaries or self-report, which can be very subjective.

In contrast, the new study made use of wrist accelerometer data, which is more objective and quantifiable, and a large genetic dataset from about 85,000 UK Biobank participants aged 40 to 70.

While talking about the study, Dr. Andrew Wood, Ph.D., a postdoctoral researcher, noted, "We wanted to find out if obesity-related genes and activity level have an interactive effect on obesity risk - if there is a 'double whammy' effect of being both at genetic risk and physically inactive, beyond the additive effect of these factors."

The researchers calculated a genetic risk score for each participant based on 76 common variants known to be associated with elevated risk of obesity.

Then, they analysed this score in the context of accelerometer data and participants' BMIs.

The scientists found the strongest evidence to date of a modest gene-activity interaction.

The findings were similar in analyses of sleep patterns. Among participants with some genetic risk of obesity, those who woke up frequently or slept more restlessly had higher BMIs than those who slept more efficiently.

The researchers are currently examining whether this interaction between genetics and physical activity differs between men and women.

They are also studying the effects of patterns of activity -- for example, whether a consistent level of moderate activity has different effects from overall low levels punctuated by periods of vigorous activity.

Dr. Frayling concluded by saying, "We hope these findings will inform clinicians who help people lose or maintain their weight, and contribute to the understanding that obesity is complex and its prevention may look different for different people. Ultimately, with further research, we may have the scope to personalize obesity interventions."

The findings were reported at the 2017 American Society of Human Genetics Annual Meeting.