Genes associated with BMI influence range of conditions

People who reduce their body mass index (BMI) can reduce the risk that related genetic variants will give rise to conditions such as type 2 diabetes and cardiovascular diseases.

BMI is emerging as an important factor for several diseases, such as type 2 diabetes and cardiovascular diseases, among others. Additionally, studies have found that numerous genetic variants can lead to an increased BMI, however, the mechanism by which this occurs is complex.

Dr Guðmundur Einarsson, research scientist at deCODE genetics in Reykjavik, Iceland, explained that 'we know that these variants are associated with many diseases' and that the main question being asked is whether 'the effect of the variants is mediated though BMI or do they have an independent effect on these diseases'.

To answer the above question, a team at deCODE genetics analysed genetic data from Iceland and the UK Biobank, to explore whether the disease risks associated with obesity-related genetic variants are directly explained by BMI.

The study, published in Nature Communications, found that BMI genetic risk scores were significantly associated with the risk for fatty liver disease, knee replacement, and glucose intolerance. This suggests that these conditions are directly related to higher body weight and, as such, reducing weight could significantly lower the risk of developing these.

Furthermore, for type 2 diabetes, heart failure, heart attacks and stroke, lowering BMI largely, but not completely, reduces disease risk. Moreover, there were differing degrees of mediation of conditions such as chronic kidney disease. This suggests that, while BMI accounts for much of the genetic risk, there are remaining associations that are independent of BMI.

It is also of note that the team found these results to be consistent regardless of sex, apart from a heart attack, which was a greater risk factor in men.

'This study highlights the critical role BMI plays in the development of diseases commonly associated with obesity, suggesting that reducing BMI could have a positive impact on lowering disease risk,' the authors wrote in Inside Precision Medicine.

Overall, this study highlights that maintaining a healthy weight, and thus BMI, is vital to managing and lowering the risk of numerous diseases. In addition, this research paves the way for further research into the mechanisms that contribute to the residual risk in the diseases not explained by BMI.