Higher COVID Infection Risk Seen in Those With Genetic Obesity, ‘Bad’ Cholesterol

Marisa Wexler MS avatar

by Marisa Wexler MS |

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COVID-19 infection risk

People who are genetically predisposed toward obesity or having high levels of so-called “bad” cholesterol — low-density lipoprotein (LDL) cholesterol — are at increased risk of contracting COVID-19, a study reported.

The study, “Causal Inference for Genetic Obesity, Cardiometabolic Profile and COVID-19 Susceptibility: A Mendelian Randomization Study,” was published in the journal Frontiers in Genetics.

Recent studies have indicated that high body mass index (BMI) — a ratio of weight to height, commonly used as a surrogate marker of obesity — is linked with an increased risk of more serious outcomes from COVID-19 infection (e.g., requiring respiratory support). However, these studies could not assess cause-and-effect relationships between obesity and COVID-19 risk.

Researchers in the U.K used a technique called Mendelian randomization to better understand the causal links of COVID-19 with obesity and obesity-related conditions. Put simply, this type of analysis uses genetic markers to determine the effect of a risk factor on a given outcome, while reducing the impact of confounding variables.

Using the UK Biobank, the researchers analyzed data for 1,211 people who tested positive for SARS-CoV-2 (the virus that causes COVID-19), and 387,079 individuals who were either untested or tested negative between March 16 and May 31. People with a positive test were more likely to be older, male, impoverished, and had a higher prevalence of heart and metabolic risk factors.

The analysis indicated that people with genetic predisposition toward a high BMI were significantly more likely to test positive for the virus, by about 15%. Waist circumference, another common measure of obesity, was not significantly associated with a positive test risk.

In addition, those with a genetic predisposition toward higher LDL cholesterol were about 58% more likely to test positive.

Other obesity-related measures, namely high blood pressure and diabetes, were not significantly associated with a risk of testing positive for the new coronavirus.

“This is the first study to identify the causal relationships between BMI, LDL cholesterol and susceptibility to SARS-CoV-2 infection,” the researchers wrote.

Subsequent analyses showed that individuals in the top 20% of genetic BMI or LDL cholesterol risk had an especially high likelihood of testing positive for SARS-CoV-2.

“Our findings support the use of BMI and LDL cholesterol as important metrics alongside other known characteristics (such as age and ethnicity) in the risk assessment of vulnerability to COVID-19 infection,” Nay Aung, PhD, the study’s lead author with Queen Mary University of London, said in a press release.

The investigators said their study has some limitations — most notably, the UK Biobank has relatively little data from non-European individuals, so the analysis included only Caucasians.

“This is especially important due to the disproportionate impact of COVID-19 on non-White individuals,” the scientists wrote. “Future MR [Mendelian randomization] studies should investigate the influence of cardiometabolic risk factors on COVID-19 in populations of African and other ancestries to better inform the public health policies.”

Still, these findings may help to inform public health policies.

“Those who fall in the at-risk obese category or those with extreme hyperlipidemia [high fat levels] in the general population may require more rigorous social distancing or shielding,” the team added.

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