Diabetes is a complex disease. Several factors must come together for a person to develop Type 2 Diabetes. While genetics may influence whether you’ll get this disease or not, other factors like environmental risk factors and a sedentary lifestyle also play a huge role.
So, is type 2 diabetes genetic? And if not, which type of diabetes is genetic? Those are the questions we are faced with today. And unfortunately, the answer is not that simple. Yes, genetics can play a role in increasing the risk for both Diabetes Type 1 as well as Diabetes Type 2, but genes alone will not determine whether you will develop diabetes or not.
If you’ve just been diagnosed with diabetes, chances are that you’re not the first person in your family who has diabetes. The details of whether diabetes can be inherited, and how this occurs, are not clear yet. About 10% of patients diagnosed with insulin-dependent Type 1 diabetes have a first degree relative with this type of diabetes. By first degree relative, we mean father, mother, sibling, twin and child.
However, when it comes to the more common type of diabetes, which is Diabetes Type 2, it has a tendency to occur in families, but this is also not very strong and not predictable. A Swedish study on Metabolic Consequences of a Family History of Non-Insulin Dependent Diabetes Mellitus concluded that abdominal obesity, insulin resistance, and decreased resting metabolic rate are characteristic features of first-degree relatives of patients with non-insulin dependent diabetes mellitus (in other words, Diabetes Type 2). And that the decrease in resting metabolic rate is partially related to the degree of abdominal obesity.
Many doctors with clinical practice treating diabetes believe that this tendency for diabetes Type 2 to run in families is, to a large extent, attributed to the fact that children of diabetics often lead a similar lifestyle as their parents, and are hence also susceptible to the same environmental and lifestyle risk factors.
A Swedish study trying to determine the value of Genetic Screening for the Risk of Type 2 Diabetes collated data from various clinical studies done across the globe to gain a deeper understanding of genetic predisposition to type 2 diabetes. The study concluded that the available data to-date does not yet provide convincing evidence to support use of genetic screening for the prediction of type 2 diabetes. They summarized the current evidence on the role of genetic variants to predict Type 2 Diabetes above and beyond non-genetic factors and discuss the limitations and future potential of genetic studies. They concluded that genetic screening for the prediction of Type 2 Diabetes in high-risk individuals is currently of little value in clinical practice.
Genes cannot be ignored when it comes to risk for developing Diabetes type 2. However, genes alone don’t determine whether you will inherit diabetes or not. If you adopt a healthier lifestyle with moderate amount of exercise, eat a clean diet and are at a healthy weight, you can beat diabetes type 2, even if it runs in your family.
We want to make something clear right away. Statistics aren’t always 100% accurate, as they are designed to gauge probability, and the conclusions are provisional. While statistics may not be in your favour when it comes to genetic predisposition to type 2 diabetes or even type 1 diabetes, don’t let them scare you.
According to a report by World Health Organization (WHO):
However, when it comes to Type 2 diabetes – there is a lot of debate. While it is true that patients with Type 2 Diabetes are more likely to know of a relative with diabetes than patients with Type 1 and, therefore conclude that Type 2 Diabetes may be genetic, there are several other things to consider here.
#1: To some extent the appearance of “clustering” of Type 2 Diabetes in families may simply just be a consequence of the fact that type 2 is so much more common than type 1 diabetes in the general population.
#2: The occurrence of multiple cases in a family may also reflect that they have shared “environmental risk factors,” such as obesity and sedentary lifestyle, and does not imply necessarily the sharing of a diabetes gene.
In general, the risk of diabetes does increase if it runs in your family. For example, your risk to developing Type 2 Diabetes increases twice as much if you have a sibling with diabetes, and it increases thrice as much if you have a parent who has diabetes. However, this increased risk does not necessarily mean you will develop diabetes Type 2; it only means that you are susceptible to it, but can beat it by reducing lifestyle and environmental risk factors.
In fact, a study done on twins in Denmark to understand the link between genetics and Diabetes Type 2 found that genetic predisposition is important for the development of abnormal glucose tolerance. Non-genetic factors, however, might play a predominant role in controlling whether a genetically predisposed individual progresses to overt Type 2 Diabetes.
We keep repeating that lifestyle and environmental risk factors may possibly play a larger role than genetics when it comes to developing Type 2 Diabetes. But what exactly are these “environmental risk factors”?
According to a report on Genetics and Diabetes by the World Health Organization (WHO), the major environmental risk factors for Type 2 Diabetes are (1) Obesity and a (2) Sedentary Lifestyle. Thus, the tremendous increase in the rates of Type 2 Diabetes in recent years has been attributed, primarily, to the dramatic rise in obesity worldwide. It has been estimated that approximately 80% of all new Type 2 Diabetes cases are due to obesity, and this holds true for adults and children alike.
Other lifestyle risk factors that can increase risk for Type 2 Diabetes include increased intake of refined carbohydrates that leads to decreased insulin sensitivity, smoking, increased intake of alcohol, job stress, and sleep deprivation.
A Swedish study trying to research on Clinical risk factors, DNA variants, and the development of type 2 diabetes found that “compared with clinical risk factors alone, common genetic variants associated with the risk of diabetes had a small effect on the ability to predict the future development of type 2 diabetes.”
While Type 1 Diabetes cannot be prevented since it’s an autoimmune disease, Type 2 Diabetes is more of a “lifestyle disease” today than anything else. Yes, you need to be extra careful if your parent/parents have Type 2 Diabetes because it does increase your genetic predisposition to the disease, having a hereditary risk doesn’t mean you’ll definitely develop the condition.
Most statistics are done assuming that we tend to eat and live the way our parents did. So if your parent’s poor lifestyle choices resulted in Type 2 Diabetes, take a good, hard look at your current lifestyle. Are you making the same mistakes as your parents which are increasing your risk factors for developing Type 2 Diabetes? In fact, changing your lifestyle to adopt healthier eating practices, a regular exercise regimen, improving sleep pattern & quality, and practicing stress relief can go a long way towards preventing Type 2 Diabetes.
Metabolic Consequences of a Family History of NIDDM (The Botnia Study): Evidence for Sex-Specific Parental Effects – http://diabetes.diabetesjournals.org/content/45/11/1585?ijkey=049729797aabba54edbdca9007d595b28344110b&keytype2=tf_ipsecsha
Genetic Screening for the Risk of Type 2 Diabetes: Worthless or valuable? – http://care.diabetesjournals.org/content/36/Supplement_2/S120
Heritability of Type II (non-insulin-dependent) diabetes mellitus and abnormal glucose tolerance – a population-based twin study – https://link.springer.com/article/10.1007%2Fs001250051131?LI=true
Diet, Lifestyle, and the Risk of Type 2 Diabetes Mellitus in Women – http://www.nejm.org/doi/full/10.1056/nejmoa010492#t=article
Active Smoking and the Risk of Type 2 Diabetes: A Systematic Review and Meta-analysis – http://jamanetwork.com/journals/jama/article-abstract/209729
Increased consumption of refined carbohydrates and the epidemic of type 2 diabetes in the United States: an ecologic assessment – http://ajcn.nutrition.org/content/79/5/774.short
Television Watching and Other Sedentary Behaviors in Relation to Risk of Obesity and Type 2 Diabetes Mellitus in Women – http://jamanetwork.com/journals/jama/fullarticle/196345
Alcohol as a Risk Factor for Type 2 Diabetes: A systematic review and meta-analysis – http://care.diabetesjournals.org/content/32/11/2123.short
Job strain as a risk factor for the onset of type 2 diabetes mellitus: findings from the MONICA/KORA Augsburg cohort study – https://www.ncbi.nlm.nih.gov/pubmed/25102002
Sleep loss: a novel risk factor for insulin resistance and Type 2 diabetes – http://jap.physiology.org/content/99/5/2008?ref=driverlayer.com/image