No, you cannot catch diabetes from other people, even by kissing them!
Diabetes is not like a cold or the flu. There are many causes of diabetes, but no form of diabetes has ever been shown to be infectious or contagious.
Most diabetes develops from an inherited tendency to get it. If you have inherited this gene, you may develop type 1 diabetes when you are exposed to something in the environment. This unknown factor triggers the onset of diabetes.
You may develop type 2 diabetes if (in addition to the gene) you gain weight and don’t exercise regularly.
There are also less common causes of diabetes, such as prolonged, excessive drinking of alcohol or having too much iron in your blood.
So while there are many causes of diabetes, catching it from another person is not one of them.
What causes Diabetes?
Many of the same factors that put you at risk for insulin resistance syndrome also increase your risk of developing diabetes, especially type 2. These risks include inherited factors, such as family history and ethnicity, and lifestyle factors such as obesity, inactivity, a poor diet, and smoking. But even if you have inherited genes or have family traits that make you susceptible to developing type 2 diabetes, it does not mean that you are destined to develop it. Lifestyle factors have a strong influence on whether you will develop type 2 diabetes. The disorder tends to be triggered by environmental stresses such as being overweight and inactive. Even people with diabetes susceptibility genes can significantly reduce their risk of diabetes by eating a healthy diet, keeping their weight within a normal range, and being physically active.
Being overweight is a very important risk factor for type 2 diabetes. The vast majority of people with type 2 diabetes are overweight. The more you weigh, the higher your risk for type 2 diabetes. Obesity, which doctors define as being more than 20 percent over your ideal weight, is the fastest-growing health problem in the United States. The number of Americans who are obese is 75 percent higher than in the early 1990s, and it continues to increase. During the same period, the incidence of type 2 diabetes rose 61 percent. The coinciding increase in obesity and type 2 diabetes is striking evidence of their close relationship.
Although the incidence of type 2 diabetes is increasing among obese children and young adults, it is still most common after age 45. For reasons that are unclear, the functioning of the insulin-producing beta cells of the pancreas tends to decrease as people age. There is also a tendency for the cells of older people to be less sensitive to insulin. Without a sufficient supply of insulin in the blood to regulate glucose, the risk of type 2 diabetes increases.
Your family health history is a key factor to consider when evaluating your risk for type 2 diabetes. If one of your parents or a sibling has type 2 diabetes, your chances of developing the disease are much higher than people in families with no diabetes. Although there is a genetic component in type 2 diabetes, it does not mean that type 2 diabetes is simply an inherited disorder. Doctors think that the interaction of several genes and environmental factors have the most impact on a person’s susceptibility to type 2 diabetes.
For example, Native Americans have the highest incidence of type 2 diabetes in the world. But a hundred years ago, the disease was rare among Native Americans. One group, the Pimas of Arizona, has an incidence of type 2 diabetes that is several times higher than that of whites of European descent, while their genetic cousins, the Pimas living in rural Mexico, have a low incidence of type 2 diabetes. What is it in the lives of Native Americans during the last century that could have produced this stunning reversal? What accounts for the disparity between the diabetes rates of the Pimas of Arizona and the Pimas of Mexico? Because the Pima groups are so similar genetically, the answer must lie with differences in their lifestyle and environment.
The Arizona Pimas switched to the typical American diet that is high in fat, salt, sugar, and calories, and their physical activity declined sharply. As a result, they became obese and their diabetes rate skyrocketed. Even though the Mexican Pimas have the same genes, their diabetes rates remain very low because they eat a high fiber diet with lots of whole grains and fresh fruits and vegetables and they engage in strenuous physical activity.
Most Americans don’t exercise enough. These lifestyle factors eating too much and exercising too little-appear to adversely affect, or “switch on,” the genes of people who are susceptible to developing type 2 diabetes. Regardless of the way the genetic vulnerability works, people with a family history of type 2 diabetes need to be especially conscientious when it comes to eating a nutritious diet, getting regular exercise, and keeping their weight down. If you are not sure if anyone in your family has had type 2 diabetes, ask your parents, aunts and uncles, and grandparents if they know of any close family members with the disorder.
People in some ethnic groups have a higher risk for type 2 diabetes than others. In North America, for example, diabetes is more of a threat to Native Americans, African Americans, Hispanics, Asians, Pacific Islanders, and Native Alaskans than it is to people of northern European descent. In Australia, diabetes affects the native (indigenous) population in greater numbers than it does other groups. The reasons for this discrepancy are still unclear, but researchers see some interesting links between ethnicity and what they think are “thrifty genes.”
Compared with the diet of our ancestors, our diet differs in many ways. Not only does it contain more fat, sugar, salt, preservatives, and other food additives, but much of our food is also processed and refined. During the processing of foods, some of the food’s nutrients may be lost. Another big difference is that food is available and easy to obtain at any time of the day or year. All we have to do is reach into the cupboard or the refrigerator and, when we run out of something, drive to the grocery store to stock up on more. And if we don’t feel like going to the grocery store, we can order our groceries online and have them delivered to our door. If we don’t feel like cooking, we can eat at a restaurant and order from a menu of diverse meal choices that are likely to contain deep-fried, high-fat, and other calorie-dense foods in enormous portions. Desserts, snacks, and treats are ever-present. Food advertising floods our senses from TV, radio, billboards, and magazines. Some researchers think that these two major differences-the abundance and easy availability of food and the minimal amount of exercise required today to obtain food-are major factors in the dramatic increase in type 2 diabetes.
Like most people, you probably feel pulled between the demands of your job and your family. When you are busy, you may be less inclined to eat right and exercise. An unhealthy diet and a lack of exercise can increase your chances of getting type 2 diabetes because they tend to lead to weight gain. Maybe you smoke cigarettes or drink alcohol to excess to relieve stress. Smoking-induced illnesses are the number one preventable cause of death in the United States. Smoking increases your risk of serious health problems, including unfavorable cholesterol levels, cardiovascular disease, high blood pressure, stroke, and type 2 diabetes. Excessive drinking can increase your heart risks by raising blood pressure and the level of potentially harmful triglycerides (fats) in the blood.
An Unhealthy Diet
Our hectic lifestyle has led many of us to shortchange ourselves when it comes to eating a healthy diet. Many Americans are consuming foods containing too many unhealthy saturated and trans fats (see page 50) and too much sugar and salt. One of the biggest reasons for this trend is our affection for fast foods, which are generally high in unhealthy fats, calories, and salt.
The consumption of fast foods has risen dramatically in the United States in recent decades and is now responsible for more than a third of all restaurant food expenditures. A 4-ounce hamburger with cheese and all the trimmings supplies 700 to 800 calories, 30 grams of fat, plus 1,100 milligrams of sodium (about half the recommended daily sodium allowance). French fries provide an additional 200 to 500 calories (depending on serving size), 40 percent of which come from fat.
Although some fast-food restaurants are now cooking their fries in healthier vegetable oils, many still deep-fry them in potentially harmful partially hydrogenated oils, which are trans fats. Trans fats are especially unhealthy because they increase the level of LDL (the “bad” cholesterol in the blood) more than other types of dietary fat. Trans fats are present in a wide variety of foods on grocery shelves, including cookies, snack crackers, potato, and tortilla chips, doughnuts, pastries, cakes, and pies. These foods are high in calories and provide a few other nutrients. Trans fats are sometimes contained in foods you would not expect to find them in, such as some breakfast cereals, breads, and broths-so read food labels carefully when shopping. Watch for the terms “hydrogenated oil,” “partially hydrogenated oil,” and “trans fats” on food labels and ingredient lists on packaged foods and avoid those that contain them.
A high intake of saturated fat, present in fatty red meat, the skin of poultry, and cheese and other full-fat dairy products, has long been known to contribute to high levels of cholesterol and other blood fats. Although the precise mechanism is unknown, excess consumption of saturated fat makes the body less sensitive to the effects of the hormone insulin, thereby contributing to insulin resistance (see page 12) and type 2 diabetes. The availability of lean meats and low-fat and fat- free dairy products makes it easy to switch from foods that are high in saturated fat to those with a lower fat content without having to give up the benefits of taste and nutrition.
You may have a sweet tooth, but the added sugar in foods hurts not only your teeth but also your waistline. Sweet desserts and snacks are okay for special occasions, but on a regular basis, they serve only to put on pounds while supplying few nutrients. In fact, filling up on sugary foods leaves you less hungry for foods that pack a higher nutritional punch.
Sugary soft drinks have been singled out in recent years as a possible contributor to the steep rise in the incidence of obesity and type 2 diabetes among both children and adults. The consumption of sugary soft drinks by adults rose more than 60 percent from the late 1970s to the late 1990s and more than doubled among children and adolescents. In fact, sugary soft drinks now make up about 7 percent of the total food consumption in the United States.
Soft drinks are also a major source of added sugars in our diet. Each 12- ounce can of soda contains 40 to 50 grams of sugar-about 9 teaspoons-and 160 to 200 calories. If you drink one can of soda each day and do not offset it by cutting back on your calorie intake in another way, you will gain 15 pounds in one year. Reducing your consumption of sugary, high-calorie soft drinks might be the single most effective step you can take to lose weight or to keep from becoming overweight.
Lack of Exercise
The human body was not meant to spend most hours of the day in a car, behind a desk, or in front of a television or a computer. But this has become our way of life. While technological advances provide many benefits, they can come at a high cost to our health, primarily by reducing the need for physical activity in our daily lives. The requirement for physical labor on the job is much less today than it was only a century ago when most people engaged in physical, often backbreaking work. Walking used to be the major mode of transportation, and most household tasks, such as washing clothes and dishes, required physical exertion.
Today, about one in four American adults lead a sedentary life, which is defined as engaging in less than 30 minutes of physical activity each day. An additional one-third of adults fail to get enough exercise to achieve health benefits. By this definition, more than half of Americans are sedentary.
TV watching is probably the leading sedentary activity in the United States. Adults spend about 30 hours each week in front of the TV, and many families have several TVs in their home, complete with remote controls. Couple this lack of physical activity with the constant exposure to TV ads for unhealthy high-calorie foods and you can understand how the increase in TV watching plays a role in the rise in obesity, the major risk factor for type 2 diabetes. In addition, a lack of physical fitness is directly related to a higher risk of death from all causes, but especially from heart disease. Physical fitness improves cardiovascular fitness, making the heart more efficient at pumping blood throughout the body.
In addition, regular exercise increases the level of beneficial HDL cholesterol in the blood. HDL cholesterol carries excess cholesterol out of the arteries and back to the liver, which removes it from the body. LDL cholesterol is the harmful form of cholesterol because it can build up in the artery walls and eventually cause a heart attack or a stroke.
Smoking cigarettes has many adverse effects on health, especially to the heart, blood vessels, and lungs. Smoking can also increase the risk of type 2 diabetes because smoking reduces the body’s ability to use the hormone insulin. When cells cannot respond effectively to insulin, they do not take in glucose from the blood in sufficient amounts and the pancreas makes more and more insulin. This condition, called insulin resistance (see page 12), contributes to the development of type 2 diabetes. In addition to reducing your body’s ability to use insulin, smoking increases the level of total cholesterol and other fats in the blood, increasing your risk of heart disease, heart attack, and stroke. Smoking also restricts the amount of oxygen that reaches your cells and tissues and replaces the oxygen with harmful carbon monoxide.
The amount of daily stress you face may also put you at risk for type 2 diabetes. Some research has found that stress-and the way a person handles it- may affect levels of blood sugar and insulin (the hormone that regulates blood sugar). Stress causes the body to release so-called stress hormones, such as adrenaline and cortisol. Under normal conditions, stress hormones are helpful because they provide the needed energy to overcome a challenge or escape immediate danger. These hormones temporarily increase the release of sugar from the liver into the bloodstream to provide energy to meet the challenge and then the liver’s release of sugar drops back to normal once the challenge is met.
But when a person is under constant stress, which can result from a traumatic life event such as the death of a loved one, cortisol stays at an elevated level over time, increasing insulin resistance and the possibility of elevated blood sugar. The high level of cortisol promotes the accumulation of fat around the abdomen, and this accumulation of excess fat in the abdominal area can make the cells even less sensitive to insulin, further increasing the risk of type 2 diabetes. For many people, stress management can be an important way to reduce the risk of health problems.
Lack of Sleep
Some medical studies suggest that lack of sleep may also be a risk factor for type 2 diabetes. Americans have been sleeping fewer and fewer hours over the past century from an average of 9 hours in 1900 to 6 hours or fewer today. Sleep loss seems to affect diabetes risk in two ways: by promoting weight gain and by interfering with the way the body uses glucose.
Sleep loss can cause weight gain by reducing the nightly production of growth hormone, a hormone that triggers both the manufacture of protein in muscle and the breakdown of stored fat, which in turn regulates the body’s proportion of muscle to fat. A reduction in growth hormone can lead to an accumulation of fat, reduced muscle mass, and obesity, the most important risk factor for type 2 diabetes.
Lack of sleep also may interfere with the body’s normal use of carbohydrates and glucose. The lack of sleep causes blood sugar levels to rise higher than usual and return to normal more slowly, and it slows the body’s production of insulin. People without diabetes who sleep fewer than 4 hours a night show signs of developing impaired fasting glucose (elevated blood sugar levels) or prediabetes, the precursor to type 2 diabetes. People who routinely fail to get enough sleep also are at risk of developing insulin resistance, which contributes to type 2 diabetes.
Impaired Fasting Glucose and Impaired Glucose Tolerance
Impaired fasting glucose is a condition in which the results of a fasting blood glucose test show a blood glucose level between 100 and 125 mg/dL after a person has fasted overnight (or 12 hours). Doctors diagnose impaired glucose tolerance when a person’s blood glucose levels are between 140 and 190 mg/dL 2 hours after drinking a sugary drink. These levels are above the normal glucose levels but below the level required for a diagnosis of type 2 diabetes. Impaired fasting glucose and impaired glucose tolerance are also features of insulin resistance syndrome.
If you have been diagnosed with impaired fasting glucose or impaired glucose tolerance, you are at very high risk of developing type 2 diabetes. Your doctor will recommend measures you can take to bring your glucose level back down and reverse the progression to type 2 diabetes.
Diabetes during Pregnancy
Gestational diabetes is a form of diabetes that some women develop when they are pregnant and that usually goes away on its own after delivery. However, having diabetes during pregnancy greatly increases a woman’s probability of developing it in a future pregnancy and of developing type 2 diabetes later in life. If you have had gestational diabetes during pregnancy, your doctor will recommend steps you can take to lower your chances of developing type 2 diabetes in the future. The children of mothers who develop diabetes during pregnancy are also at increased risk of developing type 2 diabetes at some time in their life.
Gestational diabetes poses a more immediate threat to the fetus than to the pregnant woman. If gestational diabetes goes undiagnosed, stillbirth and newborn complications are more common than in pregnancies of women who do not develop diabetes during their pregnancy.
Polycystic Ovarian Syndrome (PCOS)
Polycystic ovarian syndrome is characterized by higher than normal levels of male hormones (androgens) and by the presence of many small cysts on the ovaries that do not go away on their own, as most ovarian cysts do. Most women with polycystic ovarian syndrome are overweight, although normal-weight women can also have the disorder. Whether thin or overweight, affected women tend to carry most of their weight in the abdominal area, unlike most women, who tend to carry their weight around their thighs and hips.
When cells are not responding to insulin in a normal way, the pancreas produces larger amounts of insulin to help get sugar out of the bloodstream and into the cells. In women who are at risk for polycystic ovarian syndrome, the higher levels of insulin in the blood stimulate the ovaries to produce an excessive amount of testosterone and other male hormones. The increased levels of male hormones cause the syndrome’s characteristic symptoms, including the accumulation of fat around the abdomen.
Women who have polycystic ovarian syndrome typically have irregular menstrual periods and are often infertile because they don’t ovulate. (Ovulation is the cyclical release of an egg from an ovary.) Polycystic ovarian syndrome is usually diagnosed when a woman seeks treatment for infertility.
Lifestyle factors-including eating a healthy diet, exercising regularly, and losing weight-can significantly reduce a woman’s risk for polycystic ovarian syndrome as well as type 2 diabetes and heart disease. If you are diagnosed with the polycystic ovarian syndrome, your doctor will refer you to a dietitian or a nutritionist, who can help you develop a structured diet and exercise plan that you can adapt to your daily routine.
1. Classification and Diagnosis of Diabetes – American Diabetes Association
2. How Obesity Causes Diabetes: Not a Tall Tale – Science Magazine
3. Nonsense mutation in the glucokinase gene causes early-onset non-insulin-dependent diabetes mellitus – Nature
4. Diabetes Mellitus, Fasting Glucose, and Risk – The New England Journal of Medicine
5. Causes of Diabetes – Diabetes.co.uk