Sunday 16 February 2020

Understanding metabolic syndrome beyond obesity

Sedentary lifestyle has created a new life-threatening condition called obesity. Not just is obesity affects a person’s mental health but makes the metabolism of an individual go haywire. The very metabolic pathways (all the chemical reactions that occur in our body) that evolved to ensure that humans keep functioning in conditions of starvation get dysregulated due to several reasons and can cause weight gain in an individual causing obesity. Some of the common lifestyle factors those contribute to excessive weight gain include the familiar lack of exercise and stress. Obesity is in turn a risk factor for numerous diseases including Type II Diabetes Mellitus, Cardiovascular diseases, atherosclerosis and stroke. Many of these diseases are interrelated with respect to how they develop in the body and how one of these conditions can make you prone to developing a second disease condition. For example, a person who has atherosclerosis is at risk of developing cardiovascular disease and stroke. This interrelatedness has been described as what is known as the Metabolic syndrome. 


The usual factors that makes one susceptible to developing a metabolic syndrome are:





1. An increased waist circumference (WC)
Body mass index (BMI) is not a great measure of obesity. WC is supremely better in understanding the risks of fat deposition in the body and is used to understand risk of developing metabolic syndrome as it measures the abdominal fat.

2. High triglyceride (TGs) levels
Triglycerides are the body’s way to prepare for starvation spells. It saves fats in fatty tissues like abdomen which is a factor that contributes to waist circumference.

3. Low blood HDL levels
HDL acts as a sponge for cholesterol removing it from the body via transporting it to liver. If its level reduces then there is a higher chance of plaque (cholesterol deposition in blood vessels that cause atherosclerosis) formation.

4. High blood pressure (BP)
As happens in hypertension can lead to a higher chance of damage to blood vessels and in turn development of those fatty plaques in your blood vessels.

5. High blood sugar
This can cause not just Diabetes but also increases your risk of developing heart diseases because the excess glucose that is circulating in the blood stream gets converted to fats and in turn increases your triglycerides.

As it can be seen how all these above factors are so interconnected, which makes the treatment of metabolic syndrome a little difficult unless a major lifestyle change is done in terms of adopting an active lifestyle and taking a healthy and balanced diet.

Another factor that seems to be a puzzle piece in understanding metabolic syndrome is uric acid levels in serum. Uric acid is produced by the breakdown of proteins that we take in our diet. A common disease that happens if excess uric acid is produced in the body is gout, which causes pain in joints due to accumulation of uric acid derived crystals in joints. 

According to Dr. Wen-Harn Pan, “We noticed that Taiwanese experience almost the highest prevalence of hyperuricemia in the world. We would like to know more about its impacts than just gout. Our previous cohort studies found hyperuricemia as a strong predictive factor on cardiovascular diseases (CVD) and urate-lowering treatment can lower CVD incidence. Furthermore, our earlier study in Han Chinese confirmed that genetically exposed to high blood uric acid increased the risk of CVD events”

An increased uric acid level is, thus, also seen to be associated with the same risk factors that cause metabolic syndrome. This made scientists headed by Dr. Wen Harn Pen at National Yang-Ming University, Taiwan to understand this link further by conducting a study in which they measured serum uric acid levels of 10,000 Taiwanese along with measuring their WC, blood triglyceride, HDL, blood pressure and fasting glucose levels.

Next, they found specific genes variants (presence of a certain variant form of a gene can increase your risk for developing a certain condition) that are found to be associated with an increased waist circumference, HDL cholesterol and increased serum uric acid, this gave them specific gene variants for all these three conditions that if present can increase your likelihood of developing the respective condition. What they did next may sound a little complicated, but it comes down to understanding if the presence of these specific gene variant also coincided with the presence of one of the metabolic disturbances like an increased blood pressure, increased serum glucose level, increased triglyceride levels, increased waist circumference, and decreased HDL levels.

This may be understood as follows, if a person say has a gene variant B (of a specific gene which has three variants A, B and C), then that person is at a higher risk of developing increased blood pressure, but we don’t know what is the percentage that this individual will develop increased blood pressure. This percentage or chance can be measured by finding the number of individuals who have this gene and then checking their blood pressure, now the ones who do have a higher blood pressure can give us a percentage of how likely it would be for a person to develop high blood pressure if he has this gene variant B.

The scientists in this study found that people who have a risk of developing high serum uric acid are also at risk of developing high blood pressure and high triglyceride levels, both of which can cause metabolic syndrome. It isn’t clear if high uric acid levels can also cause obesity, although obesity can cause high serum uric acid levels. This points towards the likelihood that metabolic syndrome could occur due to factors other than obesity.

“As hyperuricemia and obesity are preventable, our findings are of relevance to public health policy and practice, and uric acid control can be prioritized to the same extent as obesity, dyslipidemia, and hypertension,” says Dr. Mahantesh Biradar, who worked as a graduate student on this study and is also the first author on this research article.

It would be interesting to see in future studies how these other factors lead to metabolic syndrome and it might serve as a tool for diagnosis and for managing this disease.

References

Original article: The causal role of elevated uric acid and waist circumference on the risk of metabolic syndrome components. International Journal of Obesity (Springer Nature). 2019. Doi: 10.1038/s41366-019-0487-9 (https://www.nature.com/articles/s41366-019-0487-9)


Read more about Metabolic syndrome here: