Causes of type 2 diabetes
Diabetes is not a single disease, rather a group of diseases (syndrome) that has multiple underlying causes. It primarily involves problems with the endocrine system and regulation of hormones. Recent scientific research and clinical trials demonstrate many causes other than hormone regulation, such as hyperactivity of the body’s own immune system (defensive line of blood cells that fighting infection and prevent invading of pathogens), positive family history and genetic makeup, and a number of environmental factors, that are not a direct cause the disease but might trigger it.
Lack of physical activity and obesity are the most common risk factors associated with diabetes. Recent research work in medical science and nutrition is also pointing out some additional risk factors linked to our modern lifestyles and habits. According to the Mayo Clinic, the incidence of diabetes has increased worldwide in the past few decades and still growing due to poor quality food (junk foods, canned food, sugar-rich food), diversion of people from an active lifestyle to passive and many others. CDC (Centers for Disease Control and Prevention) states that these environmental and socioeconomic factors are responsible for causing diabetes in approximately 80-90% of diabetes cases in the United States.
Read on to have a better understanding of what happens in the body when type 2 diabetes occurs, the underlying causes of type 2 diabetes, and specific risk factors and health problems that significantly increase the risk of type 2 diabetes.
In a healthy person, insulin is produced and secreted by the pancreas (an organ behind the stomach) to help the body process, use and store the carbohydrates (sugar) from the food you eat. Type 2 diabetes develops due to one or more of the following reasons:
1) Genetics
If you have been recently diagnosed with type 2 diabetes, especially before 40 years of age, there is a 90% chance that you are not the first person in your family who is developing diabetes. Diabetes has a strong link to genetics and family history. You are more likely to catch this condition if your sibling/s or one or both of your parents have it. Compared to type 1 diabetes, type 2 is caused and triggered by both environmental factors as well as genetics.
What does genetics mean here? Well, genetics means related to the genes. If parents carry a gene, there are good chances that it will be transferred to their offsprings. For example, if an elder generation has blue eyes or blond hairs, it is obvious that the next generation will have these traits too. This is the example of a good trait or gene. Similarly, if someone has a faulty gene, the same fault will be repeated in the next generation.
In the case of type 2 diabetes, scientists have linked multiple gene mutations to higher diabetes risk. An important thing to note is that not everyone who carries a mutation (faulty gene) will get diabetes. However, a majority of people who suffer from diabetes are found to have one or more of these gene mutations.
It is difficult to separate environmental risk from genetic risk. The former is often influenced by parents, siblings and other family members. For instance, parents with healthy eating or exercising habits are likely to transfer to the next generation. While the genetic makeup of a person plays a huge part in determining weight. Various studies conducted on twins suggest a strong link to the development of type 2 diabetes and genetics.
To date, there are several gene mutations that have been shown to affect or trigger type 2 diabetes. Although the contribution of each gene is relatively small, each additional gene mutation seems to increase the risk of developing diabetes. Scientists are also trying to find genes that can be helpful in the treatment of diabetes. This can be seen in reference to the genes present in the patients of breast cancer. The presence of BRCA1 and BRCA2 gene in breast cancer patients have a higher chance of recovery than others. These gene mutations are helpful in the treatment of breast cancer because they increase the number of receptors on the cancer cells. The new generation of targeted medicines (hormone receptor blockers) can find and target these receptors. This has set the new dimensions in the field of cancer treatment that was primarily based on chemotherapy and radiotherapy.
In general, the faulty genes inherited from parents or mutations in the genes involved in regulating glucose levels can significantly increase your risk of developing type 2 diabetes. The mutation can be in the genes that control:
- The production and processing of glucose
- How glucose levels are sensed in the body
- The regulation of insulin
- The metabolic correlation between glucose, insulin and target cells and tissues
It is difficult to pinpoint the exact cause of type 2 diabetes due to the complex interactions between genetics and environmental factor. However, that doesn’t reduce your risk by changing your habits, especially when your one or more family members have this condition.
A 2012 study of people at high risk for diabetes by Diabetes Prevention Program Outcomes Study (DPPOS) suggests that increased physical activity and weight loss can delay or even prevent type 2 diabetes. It indicates that possibility to delaying developing diabetes by changing your dietary and exercise habits.
2) Insulin Resistance
Insulin is a glucose-regulating hormone produced by the pancreas. Both types of diabetes, the type 1 and type 2, are somehow directly or indirectly related to the functioning of the pancreas. Type 1 diabetes is directly linked to the anatomy of the pancreas. It involves stimulation and hyperactivity of the body’s immune system that kills the pancreatic cells. However, the anatomical structure of the pancreas is not affected in type 2 diabetes and it continues producing and secreting insulin. In this condition, the body cells develop resistance against insulin such that they won’t be able to utilize it despite the normal production and availability.
How the body utilizes insulin is important as it helps to understand why your body develops resistance against insulin. The body is a collection of millions of cells that join together to make tissues and organs. To make and use energy, these cells and tissues need food (nutrients) in a very simple form. When you eat food, much of the nutrients present in it are broken down into a simple sugar called “glucose” in the digestive system. Glucose is absorbed and transported through the blood to these cells and tissues where it is used to produce the energy your body requires for regular metabolic activities.
Insulin is always being secreted in small amounts by the pancreatic cells. The main function of the insulin is to push the glucose present in the blood into the cells. It, along with other hormones, tightly regulates the levels of glucose in the bloodstream. When glucose levels in the blood rise to a certain level, especially after a meal, the pancreas gets stimulated and start releasing more insulin to push the excess glucose into the cells. Cells use this glucose to produce energy that is utilized in performing various metabolic functions of the body. This way, insulin causes glucose levels in the blood to drop.
To prevent hypoglycemia (low blood glucose levels), the body activates the appetite-regulating center in the brain and release hunger-stimulating hormones to eat more food and releases stored glucose from the liver. Lower glucose levels also signal the pancreas to lower the production and secretion of insulin.
People suffering from diabetes either don’t make insulin at all (in case of type 1 diabetes) or their body’s cells develop resistance against insulin (no longer are able to use insulin). This causes high blood sugars in the bloodstream and leads to type 2 diabetes. Whilst scientists are still not able to fully understand the exact cause of insulin resistance, it is a well-known fact that following one or more factors can lead the body cells to create resistance against insulin. These include;
- If you eat a high-calorie diet, high-sugar diet or high-carbohydrate diet
- If you are overweight or obese
- A sedentary lifestyle and lack of physical activity
- Chain smoking and drug abuse
- Taking steroids (high doses) over an extended period of time
- Having polycystic ovary disease or Cushing’s disease
- Having chronic stress
Besides these common risk factors, researchers have recognized that insulin resistance commonly develops in people that have:
- High levels of inflammation
- Excessive fat stored in the liver and pancreas
- High levels of insulin circulating in their blood
As your cells develop insulin resistance, the body stimulates your pancreas to fight back by producing and secreting more insulin. Over a long period of time (months and years), the beta cells in your pancreas responsible for making insulin get worn out gradually and can no longer able to meet the demand for more insulin. Years after the beginning of insulin resistance – your blood sugar levels may begin to rise and lead to the development of type 2 diabetes. It means that diabetes has been started long before the appearance of classic diabetes symptoms such as excessive thirst and increased urination. This signifies the importance of precautionary measures and healthy lifestyle adaptations you should make in your life to prevent insulin resistance – and diabetes. With time, you may also develop NAFLD (non-alcoholic fatty liver disease), a growing metabolic problem that dangerously increases your risk for heart disease and liver damage.
So a question arises here is how much increase in glucose levels can translate into the development of diabetes. By definition, diabetes is a body condition in which your blood glucose level is equal to or greater than 126 mg/dL after fasting for 8-hours. It can also be defined as a glucose level of equal to or greater than 200 mg/dL on a 2-hour glucose tolerance test along with symptoms of diabetes or having a non-fasting glucose level equal to or greater than 200 mg/dL.
3) Lifestyle
Genetics, family history, and insulin resistance do play a role in the development of type 2 diabetes, but lifestyle choices and habits also important. You can have a gene mutation that makes you susceptible to diabetes, but if you make certain lifestyle changes and take good care of your body, you may delay the onset of diabetes by 10-20 years, prevent it from developing and modify your body in a way that it responds well to the diabetic treatment.
For example, two people are carrying the same genetic mutation that they have inherited from their parents. One of them is overweight (BMI greater than 25) and inactive while the other eats well, stays physically fit and watches his cholesterol. As certain lifestyle choices have a great influence on how well your body utilizes insulin, the overweight person with an inactive lifestyle is much more likely to catch type 2 diabetes than the person with a healthy lifestyle. According to the diabetes.co.uk, development of type 2 diabetes is commonly affected by following lifestyle choices;
A. Lack Of Exercise
Lack of exercise is one of the most common lifestyle choices that affect the development of diabetes. Various studies and scientific research demonstrate that people with an inactive lifestyle are not only more susceptible to catch diabetes but also respond poorly to anti-diabetic medicines. When it comes to diabetes, physical activity has multiple benefits.
- It can help you delay or even prevent type 2 diabetes if you are susceptible.
- It boosts the metabolism – that helps to digest and absorb carbohydrates more quickly and avoid the accumulation of excess glucose in the bloodstream.
- It increases the number of insulin receptors on the target cells. This effect helps to counter insulin resistance and helps the body regulate glucose in a better way.
B. Unhealthy Meal Planning Choices
A meal plan packed full of unhealthy high-fat foods and lacking in fiber (grains, fruits, and vegetables) raises the likelihood of type 2 diabetes. Although eating excess sugar doesn’t cause diabetes, it significantly increases the risk in people with genetic susceptibility.
C. Overweight/Obesity
This is linked to unhealthy meal planning choices and lack of exercise. Both factors can cause an accumulation of fats in the belly and other body areas – leading to obesity. Being obese makes you insulin resistant and can also result in many other health conditions. Some studies also suggest that obesity is also responsible for a poor response to diabetes medicines.
4) Ethnicity
Some diseases are more prevalent in certain ethnic groups around the globe. For example, African people are less susceptible to catch malaria due to their genetic makeup. Similarly, certain ethnic groups such as African Americans, Asian Americans, Hispanic Americans, and Native Americans carry a greater risk of developing both types of diabetes than non-Hispanic whites.
Recent researches also suggest that ethnicity can also affect the age of disease onset. It is found that the average age difference in the appearance of diabetic signs and symptoms is 3-4 years.
5) Aging
Increasing age is a significant risk factor for many diseases, including diabetes. People above 45 years of age have a considerable high risk while it begins to rise significantly at about age 65. As mentioned above, certain ethnic groups can experience late sign and symptoms than others.
Besides above-mentioned causes and risk factors, other environmental factors associated with high associated risk factors may include;
- Chronic high blood pressure for more than 10 to 15 years.
- Eating a diet rich in unhealthy trans fats
- High blood triglyceride (fat) and cholesterol levels
- Gestational diabetes (diabetes during the pregnancy period)
- Giving birth to a baby weighing more than 9 pounds
- High alcohol intake and drug abuse
- Certain drugs that can damage the insulin receptors on the cells
Signs and symptoms of type 2 diabetes
Type 2 diabetes is a metabolic condition that develops due to poor regulation of blood glucose levels. The raised blood glucose levels and resistance towards insulin lead to classic indications of type 2 diabetes. It is important to recognize the early signs and symptoms of this chronic health condition that helps a person get treatment sooner – which is not only helpful in reducing the progress of the disease but also prevent severe health complications.
Type 2 diabetes is very common around the globe. According to a recent report by the CDC (Centers for Disease Control and Prevention), more than 30.3 million American adults are suffering from diabetes. The same report also demonstrates that the number of pre-diabetics (people with higher blood glucose than normal glucose levels) in the United States is 84.1 million and increasing. Prediabetic people, if not recognize the early warning signs and symptoms of diabetes are likely to develop this condition within 5 years.
Unlike most infectious diseases, the onset of type 2 diabetes is gradual that may extend over the period of 5 to 10 years. Furthermore, most of the symptoms are mild during the early stages. As a result, a majority of prediabetic people may not realize the changes their body is undergoing in all these years.
» Following is the list of the common early signs and symptoms of the type 2 diabetes:
1) Frequent Urination
Presence of excess glucose in the blood directs the body to stimulate kidneys and they react by excreting it through the urine. Glucose is a hygroscopic compound, means that it attracts or bound water molecules with it. Excretion of glucose also results in the flushing of water. This whole process leads to the more urine production and the need to pass out urine more frequently. Increased urination, over time, also become a risk factor for many other health conditions like dehydration, excessive thirst, less perspiration and urinary tract infections (UTIs) in both men and women.
People with type 2 diabetes are twice or thrice as likely to urinate as healthy people. They also have to urinate more frequently during the night hours – that disturbs their sleeping pattern. If you have recently noticed that you start going to the bathroom more often than you used to (seem to urinate more when you do go or you have to get up two to three times during night hours), talk to your physician about your condition and ask him whether you could have type 2 diabetes.
2) Increased Thirst
This sign is directly related to frequent urination. High glucose levels in the blood lead to increased production of urine and frequent urination as a result. Excretion of glucose also pulls out water and salts from the blood and leave you dehydrated. Low levels of water stimulate the thirst center in the brain and consequently you develop a dry mouth and feel thirsty.
Make sure to visit your doctor if you notice frequent urination and drinking more than usual, or that you feel thirsty more often or your mouth remains dry even after drinking fluids after regular intervals.
3) Feeling Hungry All the Time
What could be the possible relationship between diabetes and feeling hungry? Well, it’s all about the game of metabolism. Type 2 diabetic people develop resistance against insulin, which means their body is not able to regulate insulin properly. It fails to push glucose present in the blood into the cells of the muscles and all other organs of the body. During the early stages, the body tries to compensate by stimulating the pancreas to produce and secrete more insulin. This results in the accumulation of insulin in the blood.
Both factors, increased levels of insulin in the blood and insulin resistance send a signal to the brain that you are hungry. The more you eat, the more insulin is produced and the more singles are sent to your hunger center in the brain – and you will feel hungry all the time.
4) Foot Pain and Numbness
Medically known as diabetic neuropathy, this particular sign develops over time when high blood glucose levels start damaging nerves throughout the body. Although all nerves of the body are affected, it primarily targets remote nerves in the extremities such as those in fingers of the hands and feet. Some diabetic people may not experience any symptoms of the nerve damage, many others may notice pain, numbness, or tingling sensations in the extremities. Diabetic neuropathy initially develops in the feet and then progress upward as the disease advances.
5) Feminine Health Issues
High levels of glucose in the blood and urine provide fertile soil for the growth of pathogens, including bacteria, fungi, and yeast. As they multiply more quickly, most female diabetic patients are at a higher risk of catching body conditions such as bacterial infections, vaginal thrush and yeast infections. Lack of awareness and poor management of the raised blood glucose levels make managing these conditions challenging and they go on repeating themselves.
Besides feminine health issues, men also experience frequent infections due to high glucose levels in the blood such as infections of foot, skin, blood vessels, and nerves. However, these infections are not an early sign of diabetes and they usually develop in those with advanced diabetes.
6) Blurry vision
Eye problems like a blurring of vision, double vision, and floaters in front of the eyes can be indicative of type 2 diabetes. High blood sugar levels can damage the tiny blood vessels in the eyes and stimulate the accumulation of fluid in the eyes. This leads to blurring of vision and other problems mentioned earlier.
If left untreated, increasing glucose levels can damage more blood vessels and increase the risk of more severe eye conditions like cataract, retinal detachment and permanent loss of vision.
7) Feeling very tired
High blood glucose levels cause depletion of body energy stores and cause diabetic people to feel tired or extremely fatigued. It can also be due to the accumulation of metabolic waste products and toxins in body cells and tissues.
8) Slow Healing Of Cuts And Wounds
This is one of the most troublesome signs of type 2 diabetes. High levels of glucose in the blood and insulin resistance cause damage to blood vessels and the body’s nerve – that leads to the impaired circulation of the blood. This results in low supply of healing blood cells (white blood cells and platelets) to the skin. Consequently, even small wounds and cuts may take weeks to heal. The risk of bacterial and viral infections also increase with slow wound healing.
9) Skin discoloration
This is one of the early signs of diabetes. You may notice a more like or even large, dark discoloration of the skin, especially on the back of your neck. This condition is called acanthosis nigricans, and it usually appears in obese people and those suffering from insulin resistance.
Besides obesity and diabetes, such discoloration of the skin may also be caused by thyroid disorders, ovarian cysts or cancer. Birth control pills and corticosteroids are also found to causes similar patches of skin discoloration. However, it can be due to diabetes if the discoloration is present with its other common signs and symptoms.
10) Itching And Yeast Infections
Yeast infections are common in diabetic patients. Excess sugar levels in the blood and urine work as fertile soil for the yeast to grow and multiply. These infections are more common in females and mostly occur in warm and moist areas of the skin, such as the mouth, armpits and genital areas. You may feel severe itching and dryness, burning, redness, and soreness of the area infected.
11) Inflamed Gums
Diabetes can increase the risk of periodontitis – a gum disease mostly caused by a bacterial infection. A recent study on diabetic people found that patients with frequent gum infections had higher rates of developing diabetes than in coming 4-5 years. This relation seems to go both ways, i.e., having either condition greatly increases the risk other.
The reason behind this is the same, high glucose levels cause a weak immune system that leads to infections.
12) Hearing Loss
In most diabetic people, this sign may appear during the later stages of type 2 diabetes. Hearing loss is related to diabetic neuropathy, a condition that damages nerve cells in the ear and causes impaired hearing. Hearing loss is of mild to moderate intensity in most cases, while it is usually restored if blood sugar levels return to normal and diabetes is well-managed.
13) Long Naps
In a 2017 scientific review, it was found that people who took longer daytime naps were 45% more likely to suffer type 2 diabetes in coming years compared to those who napped an hour or less. However, it doesn’t mean that snoozing for a few minutes or half an hour during the daytime is the risk factor for diabetes. Rather, it’s more related to lifestyle and habits such as sleep deprivation, depression, or sleep apnea that cause you to take a nap of more than 3 to 4 hours per day.
14) Decreased Sex Drive
This male-specific problem can be an early sign of type 2 diabetes. It is collectively caused by other diabetic signs and symptoms such as lack of energy, fatigue, and sleep deprivation due to increased urination, hunger, and thirst. All these symptoms can emotionally disturb the diabetic patient and he may experience problems like decreased libido (sexual drive), impotence, and erectile dysfunction.
According to some scientific researches and clinical trials, in addition to the emotional disturbance caused by common diabetic signs and symptoms, reduced sex drive can also be due to low production of a hormone called testosterone. This hormone is responsible for the production of sperms in the male testes and also stimulate the sex centers in the brain to increase sexual drive.
15) Nausea and Vomiting
Do you feel nauseated all the time without any obvious causes? Diabetes may be to blame, especially when you have other associated risk factors like obesity and unhealthy food intake.
Insulin resistance in the body tends to shift the primary fuel of the body from glucose to fat. Increased metabolism of fats leads to the production of ketones (fatty acid molecules). These ketones are thought to upset your stomach that, in turn, results in nausea and vomiting.
