Changes in Age at Diagnosis of Type 2 Diabetes Mellitus in the United States, 1988 to 2000

I have been invited to provide a commentary to the article by Dr. Koopman et al. entitled “Changes in Age at Diagnosis of Type 2 Diabetes Mellitus in the United States 1988-2000.” This article is another great example of excellent epidemiological research from the Department of Family Medicine at the Medical University of South Carolina under the direction of Dr. Arch Mainous.

This research demonstrated a significant decrease in the age of diagnosis of Type II Diabetes from an average of 52 years of age between 1988-1994 to 46 years of age between 1999-2000. The age of diagnosis of diabetes decreased by 6 years (11.5%) over that time, while the median age of Americans increased from 32.3 years to 35.3 years of age (8.5%) over the same time frame(1-2).

As with all good research, this study raises more questions than it answers. How much are obesity and sedentary lifestyle causing this decrease in age? Will the decreased age in diagnosis allow better management of diabetes or will patients simply have complications at a younger age? Will earlier detection save the health care system from the cost of diabetic complications or will it simply increase prescription drug costs?

As Dr. Koopman points out, it’s impossible to know the exact proportion of the decreased age that is due to worsening health habits, improved clinical acumen, greater awareness of the disease, or the change in diagnostic criteria for diabetes to a fasting blood sugar > 125 mg/dL in 1997. Further studies could shed some light on this question by examining the average blood sugar values of non-diabetic Americans and the actual blood sugar numbers that lead to the diagnosis of Diabetes.

Regardless of the cause for the change in age, the impact on the healthcare system is unmistakable. I hope that earlier diagnosis will lead to better treatment and prevention of complications of this disease. However, I do not believe that the results of this study should be employed to encourage more widespread screening of asymptomatic patients for diabetes. Decisions regarding mass screening should only come from the careful analysis of important patient outcomes and cost, not intermediate outcomes or disease labels.

The biggest challenge from Diabetes to Family Physicians remains the same; how do we improve the diet and exercise habits of our own patients, so that they will not be diagnosed with diabetes when they turn 46 years of age?

1. Resident Population for Selected Age Groups: 1980-1989 [database on the Internet]. Washington (DC): United States Census Bureau. [release date 1995 Mar]. Available from: http://www.census.gov/popest/archives/1980s/estage80.txt

2. Annual Estimates of the Population by Sex and Five-Year Age Groups for the United States: April 1, 2000 to July 1, 2003. [database on the Internet]. Washington (DC): United States Census Bureau. [release date 2004 Jul 14]. Available from: http://www.census.gov/popest/national/asrh/NC-EST2003/NC-EST2003-01.xls

Competing interests:   None declared