Obesity is a major health risk that is on the rise in many places around the world. Data from the World Health Organization shows that in 2022, one-in-eight of the global population, or around 890 million adults, were living with obesity. Experts warn that unless prioritized as a critical negative health factor and effectively addressed, the rate of obesity could more than double in the years ahead.
Obesity is a chronic complex disease defined by excessive fat deposits that can impair health. Obesity is also a major risk factor for several health conditions, including cardiovascular diseases, type 2 diabetes, cancers, neurological disorders, chronic respiratory diseases, and digestive disorders. Studies into the causes and effects of obesity, as well as treatments, are being conducted worldwide.
In what could be breakthrough finding, an international team of researchers led by scientists at the University of Exeter in the United Kingdom, have discovered a novel cause for why people who lack a specific blood group are genetically predisposed to be overweight or obese. Previous studies have shown that genetic factors also have a role in people being overweight or obese.
The research team found that people with a genetic variant that disables the SMIM1 gene have higher body weight because they expend less energy when at rest.The SMIM1 gene was only identified 10 years ago while searching for the gene encoding a specific blood group, known as Vel. One in 5,000 people lack both copies of the gene, making them Vel-negative. The findings from the new research suggest that this group is also more likely to be overweight, a conclusion which could one day lead to new treatments.
The study also found that people without both copies of the gene have other measures linked to obesity, including high levels of fat in the blood, signs of fat tissue dysfunction, increased liver enzymes, as well as lower levels of thyroid hormones. The team now hopes to test whether a cheaply and widely available drug for thyroid dysfunction may be effective in treating obesity in people who lack both copies of SMIM1.
To make the discovery, the team analyzed the genetics of nearly 500,000 participants in the UK Biobank cohort, identifying 104 people with the variant that leads to loss of function in the SMIM1 gene (46 females and 44 males). The team also used fresh blood samples from both Vel negative and positive individuals.
By interrogating the effects they found in four additional cohorts of people with the SMIM1 gene variant, the researchers also found that having the variant had an impact on weight, equating to an average extra 4.6kg in females and 2.4kg in males.
Researchers at Exeter University collaborated with their colleagues at the University of Cambridge and the Sanger Institute in the UK, as well as scientists at Copenhagen University in Denmark, and Lund University in Sweden. In their study published recently, the researchers noted that obesity rates have nearly tripled in the past 50 years, and by 2030, more than one billion individuals worldwide are projected to be obese. The diseases and complications associated with obesity create a significant economic burden on healthcare systems.
The study pointed out that obesity is due to an imbalance between energy intake and expenditure, often a complex interplay of lifestyle, environmental, and genetic factors. In a small minority of people, obesity is caused by genetic variants. The new findings highlight the need to investigate the genetic cause of obesity, to select the most appropriate and effective treatment, but also to reduce the social stigma associated with it.
