NEW YORK – Using a combination of observational, epidemiological, and genetic analyses, a team from Australia and Mexico has linked habitual snoring to a range of traits, conditions, and behaviors, including body mass index (BMI) and smoking.
"Sleep-related traits such as sleep apnea, BMI, cardiometabolic, and psychiatric traits are genetically correlated with snoring," senior author Miguel Renteria, a genetic epidemiologist at the QIMR Berghofer Medical Research Institute in Australia, and his colleagues wrote, noting that Mendelian randomization analyses "suggest a potential causal relationship between higher BMI and snoring."
As they reported online on Friday in Nature Communications, Renteria and his colleagues performed a genome-wide association study that included more than 408,000 UK Biobank participants, focusing in on SNPs at 42 loci with significant snoring associations. In a series of follow-up analyses, they found that genetic factors associated with snoring include some that have been tied to a wide range of other traits and conditions.
The upper airway structure vibrations that lead to snoring during sleep are more than a noise nuisance at night. Indeed, snoring can be a signal of more serious sleep disturbances such as obstructive sleep apnea, the team explained, and can impact the sleep quality, health, and wellbeing of snorers and those sharing a bed with them.
But while habitual snoring appears to have a considerable heritable component, the researchers suggested that additional research is needed to flesh out the full suite of genetic contributors to snoring, and to identify those that correspond to other snoring-related traits and behaviors such as BMI, smoking, and alcohol use.
For the first stage of the GWAS, the team assessed more than 11 million SNPs in around 152,000 individuals who snore and some 256,000 who don't from the UK Biobank project, looking for variants that coincided with snoring after adjusting for technical genotyping differences, age, and sex.
Genetic contributors to habitual snoring tended to overlap with those associated with sleep apnea, BMI, coronary artery disease, alcohol and tobacco use, and other traits, while schizophrenia, anorexia nervosa, and educational attainment were among the traits showing negative genetic correlations with snoring.
When they focused on the potential functional consequences of the snoring-associated SNPs, using gene-based analyses, expression quantitative trait locus profiles, and other approaches, the investigators highlighted 179 genes with genome-wide significant ties to snoring. Again, the authors noted, "many of the mapped genes for snoring have been previously associated with other traits and diseases, primarily grouped into cardiometabolic, cognitive/neurological, respiratory, and psychiatric."
In another 8,000 adult participants from Australia, they reported, a polygenic risk score developed with snoring-related SNPs from the GWAS showed promise for predicting self-reported snoring and sleep features pointing to obstructive sleep apnea.
"Participants in the highest snoring [polygenic score] decile had around twice the odds of reporting recent snoring and choking or struggling for breath during sleep … compared with those on the lowest decile," the authors noted, adding that the polygenic score "showed a stronger association with increasing frequency of snoring severity."
From these and other results, the team saw hints that the genetic risk factors for snoring encompassed many of the same heritable factors involved in obstructive sleep apnea risk. In contrast, BMI and body fat appeared to have causal roles in snoring, although the genetic variants involved in snoring did not line up neatly with those implicated in BMI heritability.
"Future studies should aim at leveraging powered GWAS on craniofacial structures, alcohol, and tobacco behaviors, to assess whether they are causal of snoring," the authors concluded, "and to assess the amount of shared genetic overlap between [obstructive sleep apnea] and habitual snoring, as the latter may serve to boost the power of obstructive sleep apnea genetic studies."