Gene Linked to Heavy Smoking May Also Be Linked to High Body Mass Index

Smoking and increased body weight are two of the major health issues affecting Americans today. Both put people at risk for a reduced quality of life and potentially life-threatening health issues, such as stroke and heart attack.

In the past, researchers found that is a genetic variant that can determine how much a person smokes. Now, researchers at the University of Bristol have found a link between this variant and a high body mass index – but this is only true for people who have never smoked cigarettes.

The CHRNA5-A3-B4 gene and nicotine addiction

Nicotine addiction is a serious problem in the United States, and it is believed that this addiction is something that people can inherit from their parents. This is due to the different genetic factors that may be involved in the addiction, including the CHRNA5-A3-B4 gene.

A variant on this gene that is present in certain people can cause them to smoke more heavily than those without the variant.

Understanding body mass index

Body mass index is a type of measurement that takes your height and your weight to determine your body mass. It is pretty straightforward, and it explains body fat without actually directly measuring it. Healthcare professionals use this measurement to help determine if a person’s weight may increase their risk for associated health problems in the future, such as heart disease and certain types of cancer.

The following describes how health care professionals view body mass index in terms of what indicates a healthy weight:

• A BMI below 18.5 means that a person is considered to be underweight
• A BMI that ranges between 18.5 and 24.9 is considered to be normal
• A BMI that ranges between 25.0 and 29.9 is considered to be overweight
• A BMI that is at 30.0 or above is considered to be obese

The link between smoking and increased body mass index

The gene responsible for all of this is the CHRNA5-A3-B4 gene cluster, and a variant in this gene is responsible for these effects. It has already been established that this variant causes people who smoke to smoke more. In current smokers, this variant increases smoking, but it also tends to be related to a lower body mass index.

This study shows that how a person responds to rewards does vary from person to person. In the case of individuals with the above-mentioned gene variant, the nicotinic acetylcholine receptors that generally see nicotine as a reward are seeing food as a reward, causing overeating and a higher body mass index. Why this only appears to occur in people who have never smoked is something that researchers have yet to pinpoint.

Research is ongoing to learn more about this genetic variant, the link between the gene variant and high body mass index in nonsmokers and why smokers do not have the same experience.

If researchers can determine why this gene variant seems to be associated with a higher body mass index in nonsmokers, they may be able to look at new potential treatments for obesity.

-The Alternative Daily

Sources:
http://www.nature.com/mp/journal/v17/n9/full/mp2011122a.html
http://www.cdc.gov/healthyweight/assessing/bmi
http://www.sciencedaily.com/releases/2014/12/141204143124.htm