Diabetes and Asian and Pacific-Islander Americans

What is diabetes? • How many APIA have diabetes? • Risk factors and Type 2 diabetes • Diabetes and APIA women during pregnancy • Diabetes and cardiovascular health in APIA • Complications

Diabetes mellitus poses a rapidly growing health challenge to Asian and Pacific Islander Americans in the United States. In 1997, the Asian and Pacific Islander American (APIA) population was estimated to be about 10 million, almost a 50 percent increase since the 1990 Census and representing about 3.8 percent of the total U.S. population. This group includes people whose origins are in the Far East, Southeast Asia, the Indian subcontinent, and the Pacific Islands. Results of the 1990 Census showed that the APIA population had the greatest increase of any major ethnic group, doubling in size since the 1980 Census. The Immigration Act of 1965 and the arrival of many Southeast Asian refugees under the Refugee Resettlement Program after 1975 contributed to the increase in population observed in the past two decades.

Asian and Pacific Islander Americans in the United States were classified into 28 Asian and 19 Pacific Islander ethnic groups for the 1990 U.S. Census. These populations include people whose families originated in a variety of countries, providing great diversity in language, culture, and beliefs. Nearly 75 percent are foreign-born, but other members of this group are fifth-generation Asian-Americans.

The 1990 Census showed that 56 percent of the APIA population lived in the western States. Seventy-three percent were located within seven States: California, Hawaii, Illinois, New Jersey, New York, Texas, and Washington.

Diabetes mellitus is a group of diseases characterized by high blood levels of glucose. It results from defects in insulin secretion, in insulin action, or both. Diabetes can be associated with serious complications and premature death, but people with diabetes can take measures to reduce the likelihood of these occurrences.

Most Asian and Pacific Islander Americans with diabetes have type 2 diabetes. This type usually develops in adults, but it can also develop in children or adolescents. It is caused by the body's resistance to the action of insulin and by impaired insulin secretion. It can be managed with healthy eating, physical activity, oral diabetes medications, and/or injected insulin. Until recently, type 2 diabetes was rarely diagnosed in children and adolescents. However, recent reports highlight an increasing incidence of type 2 diabetes in children and adolescents. A small number of Asian and Pacific Islander Americans have type 1 diabetes, which usually develops before age 20 and is managed with insulin, healthy eating, and physical activity.

Diabetes can be diagnosed by three methods:

• A casual (random) plasma glucose value of 200 milligrams per deciliter (mg/dL) or greater in people with symptoms of diabetes.
• A fasting plasma glucose test with a value of 126 mg/dL or greater.
• An abnormal oral glucose tolerance test with a 2-hour glucose value of 200 mg/dL or greater.

Each test must be confirmed, on another day, by any of the above methods.

Type 1 Diabetes

Type 1 diabetes in Asian children is relatively rare; rates are significantly lower than those among non-Hispanic whites. Data from one study suggested that environmental factors might be involved in the etiology of type 1 diabetes, since rates in Japanese children in Hawaii were higher than rates of type 1 diabetes in Japanese children in Tokyo.

Prevalence data for Asian and Pacific Islander Americans are limited, but studies have shown that some groups within this population are at increased risk for developing type 2 diabetes compared with non-Hispanic white people in the United States.

A study of the prevalence of diabetes and glucose intolerance was recently conducted among Native Hawaiians in two rural communities. Results showed a 22.4 percent age-standardized prevalence of type 2 diabetes in people age 30 or older. Prevalence was highest in people age 60 to 64 who had a rate of 40 percent. This prevalence was four times higher than that of the non-Hispanic white population surveyed in the U.S. National Health and Nutrition Examination Survey II. Analysis of data collected in Hawaii from 1988 to 1995 showed that Native Hawaiians had double the rate of diagnosed diabetes that non-Hispanic white residents had.

In contrast, the prevalence of diabetes in some isolated Polynesian groups is relatively low. For example, in 1976 in Funafuti, Tuvalu, the prevalence was 1.1 percent in men and 7.2 percent in women. Researchers attributed the difference in rates to differences in physical activity. In that community, men were engaged in manual labor, but women were sedentary and consumed more calories than needed for their level of activity.

In Western Samoa, diabetes prevalence in a rural community (3.4 percent) was less than half the rate in an urban setting (7.8 percent), even after adjusting for body weight. Rural residents were much more active physically than their urban counterparts.

Recent reports in the literature highlight an increasing incidence of type 2 diabetes in youth, particularly in members of minority groups. Data about APIA youth are scarce, but trends among Asian youth may indicate future trends in the larger group. For example, studies of Japanese school children in Japan show a dramatic increase in the incidence of type 2 diabetes. Incidence in 1976 was 0.2 per 100,000 children; incidence in 1995 was 7.3 per 100,000. Junior-high-age children had an incidence of 13.9 per 100,000, which was nearly 7 times the rate of type 1 diabetes in the same group. Researchers attribute the increase in incidence to changes in food habits and rising rates of obesity.

Two categories of risk factors increase the chance of type 2 diabetes. The first is genetics. The second is medical and lifestyle factors, including obesity, diet, and physical inactivity. Individuals with impaired glucose tolerance, impaired fasting glucose, or insulin resistance are at higher risk of progressing to diabetes.

Genetic Risk Factors

Genetic background is a determining factor in the prevalence of type 2 diabetes. Few data exist on specific genetic causes in the APIA population, but some researchers have suggested that the "thrifty gene" theory may be involved in the increased prevalence of diabetes in some minority populations, particularly those with high rates of obesity. The thrifty gene theory, first proposed in 1962, suggests that population groups who experienced alternating periods of feast and famine gradually adapted by developing a way to store fat more efficiently during periods of plenty to better survive famines.

Lifestyle and Medical Risk Factors