Type 2 Diabetes. Causes And Risk Factors

Formerly known as adult-onset diabetes, type 2 diabetes develops when the body can’t properly use sugar (or glucose) as a source of energy. As a result, excess sugar circulates in the bloodstream, causing symptoms and long-term complications affecting the heart, eyes, nerves, kidneys, and immune system. 


Type 2 diabetes is the result of two closely related problems: 1) the pancreas is unable to produce enough insulin, the main hormone that controls blood sugar levels and 2) the cells in the muscle, fat, and liver don’t take enough sugar and become resistant to insulin. A combination of genetic factors and environmental factors contribute to the development of diabetes. Genetic factors,  heredity of diabetes had been covered in another article. When it comes to environmental/lifestyle factors, the most important are the following: 

Risk  factors 

Obesity is by far, the most important risk factor, affecting almost 90% of individuals with diabetes type 2. Obesity has a strong impact on insulin resistance and the progression of the disease. Obesity has a genetic component but is mostly caused by lifestyle habits such as fast food consumption and lack of regular exercise. 

Sleep apnea. Obstructive sleep apnea is closely related to obesity and is an independent risk factor for diabetes. This form of apnea is more prevalent in those with diabetes and excess weight compared with the general population and has a negative impact on blood sugar levels and how well is diabetes controlled.  Fat distribution is also important. Fat accumulated in the abdomen area indicates a higher risk compared with fat increased in the hips or thighs.  For this reason, weight circumference over 40 inches for men and 35 inches for women are considered risk factors for diabetes. 

Diet is a modifiable risk factor for type 2 diabetes. Based on research studies, a low fiber, high glycemic index diet is associated with an increased risk of diabetes. Unhealthy saturated fats and frequent consumption of processed meats and soft drinks may also play a role and also correlate with excess weight.  On the other hand, low carb diets, low glycemic index diet, and Mediterranean diet may protect or help manage diabetes.

Sedentary life/physical inactivity is a well-documented risk factor. Regular exercise (i.e. more than 3 times a week) however, helps improve insulin sensitivity and diabetes control and also manage weight. 

Age. The risk of type 2 diabetes increases with age, especially after the age of 45 and the risk is even greater if there are other risk factors. 

Smoking. Some studies found smoking as a risk factor for developing type 2 diabetes. Smoking has a negative impact on body composition, insulin sensitivity, and the function of insulin-producing cells of the pancreas.  Smoking also increases the risk of diabetes complications, particularly heart diseases, strokes, and diabetic neuropathy

Certain medical conditions. Prediabetes and gestational diabetes can, later on, cause type 2 diabetes. Polycystic ovary syndrome and abnormal blood lipid levels (high triglycerides, low HDL, or good cholesterol) are strongly associated with diabetes. Acanthosis nigricans, a condition characterized by dark, velvety skin discoloration in the armpits and neck often indicates insulin resistance.

Vitamin deficiencies. More and more research studies suggest that vitamin D has the potential to control diabetes. Low levels of vitamin D seen in the winter seem to be associated with aggravation of diabetes as it has negative effects on glucose sensitivity, insulin secretion, and inflammation. Although more studies are needed to evaluate the role of vitamin K, some research suggests that high intake of vitamin K1 correlates with better insulin sensitivity and blood sugar levels.  

Gut flora. Gut flora plays essential roles in indigestion (including how well the carbohydrates are broken down in the intestines), immune health, emotional health and may also influence gene expression. Numerous studies found that changes in the gut flora are associated with chronic illnesses and improving the gut flora can help improve those conditions. When it comes to diabetes, researchers found “clear and growing evidence” of the close relationship between the gut microbiota and diabetes which deserves future studies. Gut flora can be improved with a healthy diet including pre and probiotics and plant compounds (polyphenols), maintaining a healthy weight, and regular exercise. 

Stress is a potential contributor to chronic,  high sugar levels. Stress has a negative impact on metabolism, stimulates the release of various hormones, and causes inflammation, and all these factors can lead to higher than normal blood glucose levels. On the other hand, stress-reducing strategies like mindfulness meditation and deep breathing help improve blood sugar levels, blood pressure, and weight control.  

As you may notice, some risk factors like age and genetic predisposition can not be changed. However, most risk factors of diabetes type 2 can be modified. Simply improving the lifestyle by adopting a healthy diet, regular exercise, sleep and stress management can help prevent or better manage diabetes type 2. 

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