Eventhough elevated blood levels of high-density lipoprotein (HDL) or 'good' cholesterol, is typically thought to protect against heart disease, a University of Pittsburgh Graduate School of Public Health study has found that it may have the exact opposite effect in women with type 1 diabetes.
HDL cholesterol is known as 'good' cholesterol because it helps prevent arteries from becoming clogged.
High levels of HDL cholesterol, over 60 milligrams per deciliter (mg/dL), generally protect against heart disease, while low levels (less than 40 mg/dL for men and less than 50 mg/dL for women) increase risk.
Study researchers found the incidence of heart disease increased in both men and women with diabetes who had lower levels of HDL - below 47.5 mg/dL. For men, as levels of HDL increased, their incidence of heart disease decreased.
The same was found for women, except in those with very high levels of HDL (over 80 mg/dL) whose incidence of heart disease increased substantially. Study authors were unable to draw a meaningful comparison to male participants since only a few had HDL over 80 mg/dL.
"Although high levels of HDL are typically associated with decreased risk for cardiovascular disease, this may not be the case for women who have type 1 diabetes and HDL in the upper ranges," said Tina Costacou, lead author of the study and assistant professor of epidemiology, University of Pittsburgh Graduate School of Public Health.
"We need to examine this relationship further, but our study suggests that too much of a good thing may not always offer protection and may even be harmful for women with type 1 diabetes," Costacou added.
The study is being presented at the 70th Scientific Sessions of the American Diabetes Association.