Diabetes mellitus is a metabolic health disorder, which comes with a host of health complications, which most of us dread. Knowing its causes can help us act upon them and thereby reduce the risks of this disease.

What causes diabetes type 1 and type 2? The causes of both these types vary. The risk factors, too, differ.

The main difference is the age factor. Type 1 diabetes is a privilege of the young, while type 2 commonly affects people in the age range of 45 years to 64 years.

First of all, diabetes is not a contagious disease. One person cannot give it to another person. But, yes, there is a strong genetic cause connecting your family history to diabetes.

As explained in the post on diabetes and its types, there are two common types of diabetes mellitus: Type 1 and Type 2. There are different risk factors and causes, some responsible for Type 1 and some for Type 2.

The major and common causes of both types are listed here. You will realize that most of these causes, especially of Type 2 diabetes, can be controlled and you can prevent this disorder.

Causes of early diabetes, meaning that developing at a young age, are those specifically of type 1.

How you get diabetes?

Insulin is a hormone that is produced by the pancreas. Its main function is to help the body utilize glucose for energy and to store it for further use.

It is insulin, which is responsible for keeping our blood sugar levels within normal limits. It does this by facilitating the uptake of blood glucose by the body cells for their metabolism.

It is released into the bloodstream, as and when required, to facilitate the uptake of glucose by the body cells. When this sequence is disturbed, blood sugar levels rise above normal limits and you develop diabetes.

Why is this insulin and blood sugar sequence disturbed?

This association between insulin and blood sugar can be disturbed due to two reasons:

1)  When the pancreas fails to produce insulin or does not produce sufficient insulin, and

2) When the pancreas produces sufficient insulin but, there is a failure on the part of the body cells to take up the glucose from the bloodstream, causing the glucose to accumulate in the blood.

These are the two reasons that constitute the etiology of diabetes type 1 and 2.

Type 1 diabetes causes and risk factors

Diabetes type 1 is also called juvenile-onset or early-onset or childhood diabetes because it is commonly found in children and young people. All these names suggest that type I diabetes is a privilege of the young.

The cause of type 1 diabetes basically narrows down to deficiency of insulin.

There is no insulin production or there is insufficient production of insulin by the pancreas.

You personally have no control over this etiology as opposed to the causes of type 2, which you can control to a great extent.

The impaired insulin production occurs due to the autoimmune destruction of the beta cells of the pancreas, which are mainly responsible for insulin production.

This autoimmune response is triggered by an infection, environmental factors, or genetic causes. These include:

  1. A viral infection, which can be due to coxsackie B, rubella, or mumps.
  2. Environmental factors such as exposure to certain toxins and drinking cow’s milk during infancy that can increase your risk.
  3. Genetic factor: If your father has diabetes, it makes you more prone to develop the type 1 variety.

Sudden onset of diabetes symptoms is more common with type I diabetes, while in type 2, the symptoms present gradually or may not be present at all. In such cases, diabetes is detected accidentally on a casual blood examination.

Type 2 diabetes causes and risk factors

As mentioned above, type 2 diabetes is a disease of the adults and you usually see this type in the adults aged 45 years and above and in the elderly.

Hereditary factor: Top risk

If there is a family history of diabetes, it is more than likely that you will inherit it. It may come to you either from your father’s side or from your mother’s side or from both.

The risk of developing type 2 diabetes due to the genetic cause is stronger. You have no control over this one cause. However, taking certain precautions such as maintaining a healthy lifestyle can prevent or minimize the risk.


The risk increases as you age and is more especially after the age of 45 years. More than 75% of type 2 patients are above the age of 50 years. This is probably due to the fact that after this age people tend to exercise less and put on weight.

However, though type 2 diabetes is a condition of the adults, it is being seen to increase its incidence among the young too. According to the American Diabetes Association, about 5,000 people under the age of 20 years are diagnosed with type 2 every year.


If you are a person with a poor diet intake, lacking in proteins and fiber, your chances and risks increase.

However, diabetes due to long-standing malnutrition is rare. It is associated with insulinopenia (inadequate secretion of insulin), insulin resistance, hyperglycemia, and failure of the beta cells of the pancreas. It is also known as tropical pancreatic diabetes mellitus.

How obesity and BMI increase risk 

Obesity is one of the major causes and risk factors. This is because the excess fatty tissue builds up resistance to insulin. Due to this resistance, insulin cannot do its role in regulating blood glucose levels, and the onset of diabetes type 2 becomes imminent.

Due to a higher level of inflammation in an overweight or obese person, the membranous network in the body cells called the endoplasmic reticulum (ER) is already stressed.

This already stressed ER has to process more nutrients in an obese person due to his overeating habits. This dampens the insulin receptors on the cell surface.

Insulin uptake suffers and the person develops insulin resistance. This translates into high levels of blood glucose and the subsequent onset of diabetes type 2.

A high body mass index (BMI) is a strong and independent risk factor. The higher the BMI, the higher is the risk.

Waist size

An increased waistline can be an indication of insulin resistance. In men with waists larger than 40 inches and in women with waists larger than 35 inches, the risk of insulin resistance increases. A large waist can significantly increase your risk of prediabetes or borderline diabetes.

Sedentary lifestyle: a major cause

A sedentary lifestyle or a lifestyle of physical inactivity is a major risk factor. If you stay physically active, it burns the glucose in the blood to convert it into the energy required for physical activity.

It also makes your body cells more sensitive to insulin. A sedentary lifestyle will allow glucose to build up in the blood.

When you are inactive, your body cannot use insulin effectively. This is known as insulin resistance or insulin sensitivity.

If this occurs, the pancreas sends out even more insulin to combat this situation, but instead of turning the food into energy, it stores the excess amount as fat.

Certain drugs

Prolonged administration of certain therapeutic drugs increases the risk and can make the person a potential candidate. Some of these drugs are strongly diabetogenic while some carry a lower risk.

Strongly diabetogenic drugs include steroids, antipsychotics such as clozapine and olanzapine, and some immunosuppressive medications.

Examples of mild diabetogenic drugs are antihypertensive agents and statins.


Prolonged exposure to a toxin produced by staphylococci aureus infection can trigger the onset of diabetes type 2 including insulin resistance, glucose intolerance, and systemic inflammation.

High blood pressure

These two conditions, hypertension and diabetes, are often seen together especially in those who have high systolic pressure.

High blood pressure above 140/90mm of Hg increases the risk of diabetes and its complications.

Previous research showed that people with high blood pressure were at a 50% increased risk. Later, further studies found the risk to be more than 70%.

The link does exist, but researchers cannot say whether hypertension is a cause or a risk factor.

High cholesterol and triglyceride levels

Similarly, patients with high triglycerides and elevated cholesterol are more prone to develop high blood sugar levels. The link between diabetes and cholesterol is an established fact.

According to the American Diabetes Association,

“From an initial perception that a disorder of glucose metabolism was the primary event in the pathogenesis of type 2 diabetes, there is now a growing appreciation that chronic elevation of FFA levels is an early event that contributes to the development of this disease. FFAs induce insulin resistance, which increases with FFA levels”.

— where FFAs stand for free fatty acids


Ethnicity is a surprising inclusion among diabetes risks. It is not known why people belonging to certain races harbor a higher risk. Its prevalence and risk factors among ethnic minorities are very clearly evident.

African Americans, Mexican Americans, American Indians, Native Hawaiians, Pacific Islanders and Asian Americans are more prone to develop diabetes type 2 than the white people.

The possible reason given so far is that these people tend to be overweight and suffer from high blood pressure.

Polycystic ovarian syndrome (PCOS)

Polycystic ovarian syndrome significantly increases the diabetes risk among women. This is shown by the fact that many women with PCOS have diabetes.

PCOS causes insulin resistance, which leads to type 2 diabetes setting in. Research indicates that women with PCOS are three to five times more likely to develop type 2 diabetes than women without PCOS.


Alcohol in limits has no bearing on the cause of diabetes. It is the excess amounts that increase your risk.

Heavy alcohol consumption causes inflammation of the pancreas and this can significantly impair its insulin production.


Smoking causes insulin resistance and this affects the uptake of insulin by your body cells causing blood sugar levels to rise.

Heavy smokers (20 cigarettes and more) double their risk of developing diabetes type 2 as compared to nonsmokers.

Correcting certain myths

  •  Consuming sweets does not cause diabetes.
  •  Stress does not cause it either.

However, in a diabetic person, the above two factors will worsen the existing diabetes.

Action step:

Some of the factors mentioned above are the major causes meaning they are more common. If you harbor any of these, you should try these effective natural tips to prevent diabetes.

But, if you are already diabetic, take your treatment religiously. Follow what is mentioned below because if you act irresponsibly, you could head for uncontrolled diabetes, the complications of which have a low prognosis and high mortality rate.