Diabetes is a disease that affects people of all ages. However, the incidence of type 1 diabetes, type 2 diabetes and other forms of this disorder vary from one age group to another.

Type 2 diabetes (formerly called adult-onset diabetes) accounts for 90 to 95 percent of all diabetes cases. In this form, the body produces insulin but is unable to use it properly to break down glucose (blood sugar) for energy.

Like many other conditions, such as cardiovascular disease, the risk for developing type 2 diabetes increases with age and is most often diagnosed after the age of 45. However, the number of obese children has risen dramatically over the years and so has the number of children and teens diagnosed with type 2 diabetes.

Type 1 diabetes (formerly called juvenile diabetes) is often diagnosed before age 20. In this form, patients can no longer produce insulin. Latent autoimmune diabetes of adulthood (LADA) is a variation of type 1 diabetes that usually develops after age 30 and is sometimes misdiagnosed as type 2.

Other forms of diabetes include maturity-onset diabetes of the young (MODY), caused by a genetic abnormality. This type of diabetes is usually diagnosed in young adults but has also been seen in teens and children. Gestational diabetes can affect any woman of childbearing age who becomes pregnant.

Many risk factors for type 2 diabetes and gestational diabetes can be controlled, such as diet, weight and level of physical activity. By controlling these risk factors earlier in life, a person has a better chance to delay or perhaps even prevent the onset of diabetes later in life.

Type 1 diabetes, LADA and MODY are not tied to controllable risk factors such as obesity. However, early diagnosis and management of these types of diabetes can prevent many health complications.

Until recently, diabetes was classified by age. What is now called type 1 diabetes was known as juvenile-onset diabetes and type 2 diabetes was known as adult-onset diabetes. However, type 1 diabetes can occur in adults (though usually young adults), and type 2 diabetes is increasingly being seen in children because of the rise in obesity.

Type 1 diabetes involves an inability to produce insulin, which is required to break down glucose (blood sugar) for the body to use as energy. It is usually diagnosed before age 40. About half of all people diagnosed with type 1 diabetes are younger than 20 years of age, according to the American Diabetes Association. Younger people are also at risk for maturity-onset diabetes of the young (MODY), a genetically acquired form of diabetes.

Type 2 diabetes, by far the most common form of diabetes, occurs when the body produces insulin but is unable to use it properly to break down glucose. It is most often seen in older adults, with half of all cases diagnosed in people 55 and over, according to the ADA.

Age plays a significant role in the risk of developing type 2 diabetes, especially after age 45. Because aging is an inevitable process, prevention strategies focus on diabetes risk factors that can be controlled, such as diet and physical activity.

Children and teens are at risk for several forms of diabetes: type 1 diabetes, type 2 diabetes, maturity-onset diabetes of the young (MODY) and a rare inherited condition called Wolfram syndrome. U.S. government health agencies estimate that:

• 176,000 Americans under age 21 (0.22 percent of that age group) have diabetes.
  
  
• One in every 400 to 600 children and adolescents has type 1 diabetes.
  
  
• About 2 million American adolescents have prediabetes.
  
  
• More than a third of Americans born in 2000 will eventually develop diabetes.

The National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK) cautions that data on pediatric diabetes are inadequate. Although authorities generally agree that the prevalence of diabetes in childhood is growing, federal estimates were slightly reduced in 2005 because they were based on five years of data instead of the most recent three years, as was previously done. Improved reliability is expected upon completion of a major five-year project, SEARCH for Diabetes in Youth.

Facts about diabetes in young people include the following:

• Type 1 diabetes in youth
  
  
• • Risk is higher than virtually any other chronic childhood disease.
    
    
  • Occurs most often between ages 10 to 12 in girls, and 12 to 14 in boys.
    
    
  • Can lead to a condition called double diabetes in which insulin resistance develops, typically because of excess weight, lack of exercise and poor eating habits.
    
    
• Type 2 diabetes in youth
  
  
• • Tends to affect those who are older than age 10.
    
    
  • Is also being increasingly reported in younger children because of the rise of childhood obesity. 

MODY is a genetic form of diabetes that is sometimes described as a variation of type 2 diabetes. It usually affects young adults but is also seen in teens and children. Unlike standard type 2 diabetes, patients do not tend to be overweight or sedentary.

A genetic mutation is responsible for the impaired insulin secretion that is characteristic of MODY. In most cases, those with MODY do not have insulin resistance.

Wolfram syndrome is a rare genetic condition that includes insulin-dependent diabetes, loss of hearing, loss of vision and an endocrine disorder called diabetes insipidus.

There is also a rare diabetic condition called Mauriac syndrome (diabetic dwarfism) that causes enlarged liver, shortened stature and delayed puberty in children.

The risk of type 2 diabetes increases as a person ages until it peaks in middle age. The risk for adults of being diagnosed with diabetes is greatest in middle age. According to statistics from the Centers for Disease Control and Prevention in 2007, of the estimated 1.5 million American adults diagnosed with diabetes in 2005:

• 727,000 (48 percent) were diagnosed between ages 40 and 59
  
  
• 575,000 (38 percent) were diagnosed after age 59
  
  
• 202,000 (13 percent) were diagnosed between ages 20 and 39

The CDC adds that of the 20.8 million Americans estimated to have diabetes (7 percent of the population), 20.6 million are 20 years or older and 10.3 million are 60 or older. One in five Americans over age 60 has diabetes. Most of these patients have type 2 diabetes. The incidence of diabetes is even higher in older people from high-risk populations, such as Native Americans, Hispanics, Asian Americans and African Americans.

Other forms of diabetes that affect adults include latent autoimmune diabetes of adulthood (LADA), which is a variation of type 1 diabetes, and gestational diabetes, which can develop in any nondiabetic woman during pregnancy.

As people live longer, a new population of diabetes patients is emerging. The American Diabetes Association reports that many cases of diabetes in elders go unreported or undiagnosed, and that the overall diabetes rate is likely higher than the official figures. The CDC estimates that 30 percent of diabetic Americans overall have not been diagnosed.

As a person ages, two factors occur that increase the susceptibility to diabetes:

• Production of insulin decreases as the pancreatic beta cells become older.
  
  
• Insulin resistance increases because lean tissue is lost and replaced by fatty tissue, particularly in the abdomen (central obesity). Sensitivity to insulin also decreases in other tissues throughout the body.

Researchers have also found that insulin resistance increases in older people as the metabolic activity of their mitochondria decreases. Mitochondria provide power for the cells, and their decreased function may increase the cells’ resistance to insulin.

Several factors can also make diabetes management more difficult in patients who are older:

• Lifetime habits and physical condition may make it more difficult to modify lifestyle behaviors that increase the risk of type 2 diabetes. These include obesity, smoking, unhealthy diet and lack of exercise.
  
  
• Coexisting conditions such as high blood pressure (hypertension) and unhealthy levels of cholesterol and other blood fats (hyperlipidemia) may hamper the effectiveness of diabetes treatments.

• Complications such as dehydration and hyperosmolar hyperglycemic nonketotic syndrome (HHNS) may appear more suddenly and with greater severity than in younger patients.
  
  
• Diabetic diseases such as diabetic nephropathy and retinopathy are more common in people with long-time diabetes.

• Decreased mental and physical functioning may make it more difficult to adhere to a treatment program.
  
  
• Adverse drug reactions are more likely because older people often take more medications.
  
  
• Limited income or insurance may hinder access to medication.

In addition, advanced age and diabetes are both risk factors for sexual dysfunction.

There are several risk factors for diabetes that cannot be controlled, controlled, such as age, family history, genetics and race. However, lifestyle factors, including weight, exercise habits and smoking, can be controlled. As a person ages, there is an increased chance of developing certain types of diabetes, particularly type 2. For this reason, people should strive to reduce their risk factors as much as possible to decrease the chance of developing diabetes.

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients (and parents) may wish to ask their doctor the following questions about age and diabetes:

1. How does my age affect my risk for diabetes?
   
   
2. Which forms of diabetes are most common at my age?
   
   
3. Are there ways I reduce my risk?
   
   
4. If I already have diabetes, how does age affect the disease process?
   
   
5. Does my age affect how often I should see you and medical specialists?
   
   
6. Does my age affect how often I should have certain tests, such as eye exams and assessments of kidney function?
   
   
7. How does my age affect my risk of diabetic complications, such as heart disease and eye damage?
   
   
8. How do my diabetes and my age affect my risk of sexual dysfunction?
   
   
9. Why does diabetes seem to be getting more common in children? Are my children at risk? Should they be screened for diabetes?
   
   
10. How can I help keep my child from getting diabetes?