Most recent update: Thursday, November 14, 2019 - 09:22

Bariatric News - Cookies & privacy policy

You are here

Inactivity, sleep and obesity

Inactivity and restless sleep exacerbate genetic risk of obesity

The outcomes revealed evidence of gene-activity interactions in the UK Biobank

Low levels of physical activity and inefficient sleep patterns intensify the effects of genetic risk factors for obesity, according to results of a large-scale study presented at the American Society of Human Genetics (ASHG) 2017 Annual Meeting in Orlando, FL. These results confirm and strengthen previous findings based on self-reported activity.

"Until recently, physical activity and sleep patterns could not be measured with as much precision as genetic variants, and we relied on diaries or self-report, which can be very subjective," said the head of the study, Professor Timothy Frayling from the University of Exeter Medical School said. “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.”

For the study, ‘Gene x environment interactions in the UK Biobank study: Evidence that both physical inactivity and sleep inefficiency accentuate the genetic risk of obesity’, the researchers used the first genetic data release of 120,000 individuals from the UK Biobank study, 19,229 of whom had accelerometer data. From accelerometer data, they derived a variety of measures for physical activity and sleep, including total physical activity, bouted activity, sleep duration and sleep efficiency.

They used BMI as the outcome and tested associations with genetics and accelerometer derived measures of activity and sleep, as well as self-reported measures of activity and sleep (n=109,142). They also analysed individual BMI variants and a genetic risk score (GRS) for obesity (76 variants) and performed several negative control experiments mimicking environmental factors with similar properties as activity.

"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," said Dr Andrew Wood, postdoctoral researcher, who presented the work Dr Andrew Wood, postdoctoral researcher, who presented the work.

The outcomes revealed evidence of gene-activity interactions in the UK Biobank. For example, the effect of the BMI GRS on BMI was larger in the 50% of people reporting less physical activity, with 10 additional BMI-raising alleles associated with a 3.6kg increase in weight for someone 1.73m tall in the least active 50% of individuals versus 2.8kg in the most active 50% (Pinteraction=5x10-6).

This observation was consistent within individuals with objective measures of activity. However, they also observed (weaker) evidence of interaction in the negative control experiments, suggesting residual confounding was present. In addition, they also identified a nominal interaction effect between the GRS and sleep efficiency (p=0.023), with stronger BMI genetic effects in individuals sleeping least efficiently, subjects 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.

"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," said Frayling. "Ultimately, with further research, we may have the scope to personalize obesity interventions.” 

Want more stories like this? Subscribe to Bariatric News!

Bariatric News
Keep up to date! Get the latest news in your inbox. NOTE: Bariatric News WILL NOT pass on your details to 3rd parties. However, you may receive ‘marketing emails’ sent by us on behalf of 3rd parties.