For men, but not women, higher levels of the protein albumin in the urine are a strong risk factor for diabetes, reports a study in the November 2008 issue of the Journal of Hypertension.

Men’s risk of diabetes rises steadily along with urinary albumin excretion (UAE) level, independent of other diabetes risk factors, the researchers conclude. The lead author was Dr. Jean-Michel Halimi of François Rabelais University, Tours, France.

The study included 3,851 men and women from an ongoing study of risk factors for insulin resistance syndrome, a pre-diabetic state. The subjects, aged 30 to 64 years, underwent measurement of UAE. Increased UAE levels, or microalbuminuria, are a key early sign of kidney disease - often caused by diabetes. Microalbuminuria is defined as a UAE between 20 and 200 mg/L (milligrams per litre).

The subjects were also evaluated for the five risk factors that make up the metabolic syndrome: elevated waist circumference, high triglyceride level, low HDL (”good”) cholesterol level, high blood pressure, and high glucose level. People with any three of these risk factors are considered to have metabolic syndrome, which is linked to an increased risk of cardiovascular disease and diabetes.

As Albumin Excretion Increases, So Does Men’s Diabetes Risk

During nine years’ follow-up, diabetes developed in 171 subjects (132 men and 39 women). For men, the risk of diabetes increased steadily along with UAE. Diabetes risk was approximately doubled for men with UAE levels meeting the definition of microalbuminuria. For men with UAE levels over the 200 mg/L cut-off point for “macroalbuminuria” - indicating established kidney disease - the risk of diabetes was more than quadrupled.

For women, UAE was not a significant risk factor for diabetes.

The link between UAE and diabetes was even stronger after exclusion of men who had abnormal glucose levels at the beginning of the study. It also remained significant after adjustment for a wide range of other risk factors, including body weight, physical activity, smoking, and waist circumference; and for the development of insulin resistance during the first three years of follow-up.

Type 2 diabetes usually causes no symptoms in its early stages, and can go undiagnosed for years before serious complications occur. New approaches are needed to identifying patients at increased risk of diabetes, who may benefit from preventive measures. Patients with insulin resistance or metabolic syndrome are more likely to have elevated UAE. However, the relationship between UAE and the development of diabetes - with or without metabolic syndrome - has been unclear.

“UAE is a potent independent predictive marker of diabetes mellitus in men but not in women,” Dr. Halimi and colleagues write. For men, diabetes risk rises steadily along with UAE level, independent of several major diabetes risk factors. The reasons for this relationship are unknown, although many interrelated factors may be involved.

“In conclusion, our findings indicate that albuminuria may improve the identification of men at risk of diabetes mellitus, beyond the presence of metabolic syndrome,” Dr. Halimi and colleagues conclude. Measuring UAE may provide a simple new test to assess diabetes risk. The next step is studies to find out whether treatments to lower urine albumin can help to reduce the risk of diabetes (Newswise).