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Undiagnosed Diabetes and Related Eye Disease in Mexican-Americans--A Call for Increased Detection

June 22, 2001

A research study of the Mexican-American population over age 40 found that the rate of diabetes in this group is 20 percent–almost twice that of non-Hispanic Whites–and that 15 percent of those with diabetes did not know that they had the disease before their participation in the study. The findings suggest that increased efforts to improve diabetes detection in Mexican-Americans may be warranted. These data are reported in a research paper published in the July 2001 issue of Diabetes Care, a journal of the American Diabetes Association.

Of the 15 percent who were newly diagnosed with diabetes, 23 percent had early to moderate diabetic retinopathy, a potentially blinding eye complication of diabetes, and another nine percent had advanced diabetic retinopathy and were in immediate danger of losing some vision. The study was sponsored by the National Eye Institute (NEI) and the National Center on Minority Health and Health Disparities (NCMHD), components of the Federal government’s National Institutes of Health (NIH).

“These findings serve as a ‘red flag,’” said Paul Sieving, M.D., Ph.D., director of the NEI. “The longer a person has untreated diabetes, the more likely the disease will cause complications.

In fact, diabetes increases the risk of blindness 25-fold over the general population. Peoplewith diabetes should be encouraged to seek regular eye care to increase the chances of early detection and timely treatment of diabetic eye disease.”

“Untreated diabetes can lead to devastating complications,” said John Ruffin Ph.D., NCMHD director. “These findings underscore the importance of early diagnosis and treatment, especially in minority populations who suffer from a disproportionately high prevalence of Type 2 diabetes.”

“The onset of diabetes in the survey’s newly diagnosed group was most likely between four to seven years earlier,” according to Sheila West, Ph.D., El-Maghraby Professor of Preventive Ophthalmology at Johns Hopkins University School of Medicine in Baltimore and lead author of the paper. “It is important that diabetes be detected early, so it can be controlled before complications appear.” Previous studies sponsored by the National Institute of Diabetes and Digestive and Kidney Disease at the NIH have shown that people with diabetes who keep their blood sugar, cholesterol, and blood pressure levels as close to normal as possible have much less vision loss, heart disease, kidney, and nerve damage.

“With early detection, timely laser surgery, and appropriate follow-up care, people with advanced diabetic retinopathy can reduce their risk of blindness by 90 percent,”Dr. Sieving said. “But if people do not realize they have diabetes, their blood sugar levels may be high enough to cause vision loss and other complications before they receive appropriate medical care.”

The study of the Mexican-American population also found that:

  • The rate of diabetes in the Mexican-American community age 40 years and older was 20 percent, rising from 10 percent in those aged 40-49, to 32 percent in those aged 70-79. This high prevalence of diabetes among Hispanics of Mexican origin–generally 2-2 1/2 times higher compared to non-Hispanic Whites–is similar to that reported by other studies.
  • The rate of diabetic retinopathy in those with diabetes was 48 percent, a number similar to that of non-Hispanic Whites. Prior to the survey, there had been conflicting reports about the rate of diabetic retinopathy in Mexican-Americans with diabetes. In this survey, it is estimated that one-third of Mexican-Americans with diabetic retinopathy could have delayed or prevented eye complications with early detection and control of their diabetes.
  • The rate of diabetic retinopathy increased with higher blood sugar levels and longer duration of diabetes.

The study–called Proyecto VER (Vision Evaluation and Research)–assessed visual impairment in a population-based sample of 4500 Mexican-Americans age 40 and older living in Tucson and Nogales, Arizona. Proyecto VER was designed to address the prevalence and causes of visual impairment including diabetic retinopathy in this population group. In the United States, the Mexican-American population is the second largest minority group, and if current trends continue, will become the largest minority group during this century.

About 16 million people in the United States have diabetes, the most common cause of blindness, kidney failure, and amputations in adults. One-third of people with diabetes do not know they have it. Type 2 diabetes, which accounts for about 90 percent of diabetes in the US, is most common in people who are overweight, inactive, over age 40, and have a family history of diabetes. The disease is also more common in minorities; African Americans, Hispanic/Latino Americans, Native Americans, and some Asian Americans and Pacific Islanders are at especially high risk.

People with Type 2 diabetes first develop insulin resistance, a disorder in which muscle, fat, and liver cells do not use insulin properly. At first, the pancreas compensates by producing more insulin, but gradually its capacity to secrete insulin in response to meals falters, and the timing of insulin secretion is abnormal. After diabetes develops, pancreatic production of insulin continues to decline. Many people can control their blood glucose by following a careful diet and exercise program, losing excess weight, and taking oral medication. However, the longer a person has Type 2 diabetes, the more likely he or she will need insulin injections, either alone or combined with oral medications.

About 5-10 percent, or one million people with diabetes, have Type 1, formerly known as juvenile onset diabetes or insulin-dependent diabetes. This form of diabetes, which usually occurs in children and adults under age 30, develops when the body’s immune system attacks the insulin-producing cells of the pancreas.

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The National Eye Institute (NEI), the Federal government’s lead agency for vision research, is part of the National Institutes of Health (NIH) under the US Department of Health and Human Services. NEI-supported research leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness.

The NIH’s National Center on Minority Health and Health Disparities (NCMHD) conducts and supports research, training, information dissemination and other programs aimed at reducing the disproportionately high incidence and prevalence of disease, burden of illness, and mortality experienced by certain American populations, including racial and ethnic minorities and other groups with disparate health status, such as the urban and rural poor.

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  • West SK, Klein R, Rodriguez J, Muñoz B, Broman AT, Sanchez R, Snyder R, Proyecto VER. Diabetes and Diabetic Retinopathy in A Mexican-American Population: Proyecto VER. Diabetes Care. 2001 Jul. PubMed


National Center on Minority Health and Health Disparities