Diabetics – Epidemiology

Over 18 million Americans have diabetes; of these, about 5 million do not know they have the disease (1).

Type 1 diabetes accounts for 5-10% of cases, affecting 1 of 400 children and adolescents.

Type 2 diabetes is extremely common, accounting for 90-95% of all cases of diabetes. This form of diabetes can go undiagnosed for many years, but the number of cases that are being diagnosed is rising rapidly, leading to reports of a diabetes epidemic.top link

The Type 2 Diabetes Epidemic

When people think of epidemics, they often think of infectious diseases such as SARS, HIV, or the flu. However, the prevalence of type 2 diabetes is now at epidemic proportions. In the United States, diabetes accounts for over 130 billion dollars of health care costs and is the fifth leading cause of death ( 2). The number of new cases being diagnosed continues to rise. It has been estimated that of the children born in the year 2000, 1 of 3 will suffer from diabetes at some point in their lifetime ( 3). Diabetes is predicted to become one of the most common diseases in the world within a couple of decades, affecting at least half a billion people ( 4).

Estimate your risk of developing Type 2 Diabetes

In the past, type 2 was rarely seen in the young, hence its original name of “adult-onset diabetes”. But now type 2 diabetes is increasingly being diagnosed in young adults and even in children. In Japan, more children suffer from type 2 than type 1 (“juvenile onset”) diabetes. This young generation of diabetics will have many decades in which to develop the complications of diabetes.

In 1990, 4.9% of the American population were diagnosed with diabetes (see Flash Animation 1). This increased to 7.9% by the year 2001 ( 5).top link


The driving force behind the high prevalence of diabetes is the rise of obesity in the population. In today’s society, it can be difficult to maintain a healthy weight. We have the combination of ample food and a sedentary lifestyle. This is in stark contrast to only a couple of hundred years ago, when people were more active and food supplies were not as abundant. As a result, many of us are heavier than we should be.

Calculate your ideal weight

Being overweight or obese is defined by a calculation called the Body Mass Index (BMI). It is a calculation that takes your height and weight into consideration and gives you a score. A score of 18–24.9 is a healthy weight. If you are overweight, your score lies within the range to 25–29.9; a score of 30 and above indicates obesity.

Calculate your BMI

In 1991, it was estimated that 12% of the population were obese ( 5). By the year 2001, this had increased to an estimated 20.9% of the population; this represents over 44 million obese adult Americans. A more recent study estimated that a record 30% of the American population are now obese ( 6) (see Flash Animation 2).

Obesity is a major problem for the United states. Every year, an estimated 300,000 US adults die of causes related to obesity ( 7). Obesity is also a huge economic burden, accounting for up to 4% of healthcare costs in the United States ( 8).top link

Thrifty Genes

Epidemics of infectious diseases increase when there is increased spread of the infectious agent and decrease when the number of victims who are susceptible falls (they either become immune or they die). An epidemic of a genetic disease such as type 2 diabetes is similar. The number of cases rises when there is a rise in environmental risk (abundant food supplies, lack of activity) and decreases when the number of susceptible individuals falls (by deaths from the complications of diabetes).

The classic example of an epidemic of diabetes is found on an remote island in the Pacific Ocean, the island of Nauru. Before the turn of the 20th century, the lifestyle of Nauruans was harsh. The soil was poor, agriculture was difficult, and frequent episodes of starvation were common. Despite these adverse conditions, the islanders were noted to be “heavy”. In 1922, it was discovered that Nauru contained phosphate rock, which was then mined for use in fertilizer, and for which the islanders received royalties. Over several decades, the Nauruans became extremely wealthy, and with their new-found riches came major lifestyle changes. Food was now abundant and could be bought from stores. Instead of fishing and farming, Nauruans now led sedentary lives. By the 1950s, type 2 diabetes exploded from being non-existent in this population to affecting 2 of 3 adults over the age of 55 and becoming a common cause of death.

The case of the Nauruans is an extreme case of how type 2 diabetes can rapidly reach epidemic proportions, and “thrifty genes” may be involved. It has been postulated by Neel ( 9) that genes that are metabolically thrifty give a survival advantage in times when there is a constant threat of famine and starvation. When food is abundant, these genes aid the efficient metabolism of the food, enabling rapid build up of fat stores. This enabled people like the Nauruans to survive food shortages later on. But when food is always abundant, a thrifty genetic makeup turns into a survival disadvantage. Thrifty genes cause obesity, which in turn predisposes to diabetes. The epidemic that took hold of the island of Nauru is now emerging in developing countries and already has a firm hold on the developed world.top link

1. National Diabetes Statistics . National Diabetes Information Clearinghouse, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

2. Hogan P, Dall T, Nikolov P. Economic costs of diabetes in the US in 2002. Diabetes Care 2003; 26(3):917-932. (PubMed)

3. Narayan KM, Boyle JP, Thompson TJ, Sorensen SW, Williamson DF. Lifetime risk for diabetes mellitus in the United States. JAMA 2003; 290(14):1884-1890. (PubMed)

4. King H, Aubert RE, Herman WH. Global burden of diabetes, 1995-2025: prevalence, numerical estimates, and projections. Diabetes Care 1998; 21(9):1414-1431. (PubMed)

5. Mokdad AH, Ford ES, Bowman BA, Dietz WH, Vinicor F, Bales VS, Marks JS. Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. JAMA 2001; 289(1):76-79. (PubMed)

6. Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults, 1999-2000. JAMA 2002; 288(14):1723-1727. (PubMed)

7. Allison DB, Fontaine KR, Manson JE, Stevens J, VanItallie TB. Annual deaths attributable to obesity in the United States. JAMA 1999; 282(16):1530-1538. (PubMed)

8. Allison DB, Zannolli R, Narayan KM. The direct health care costs of obesity in the United States. Am J Public Health 1999; 89(8):1194-1199. (PubMed)

9. Neel JV. Diabetes mellitus: a "thrifty" genotype rendered detrimental by "progress"? JAMA 1962; 14:353-362. (PubMed)

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This post was written by admin on June 18, 2009


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