Hardening arteries are linked with heart disease and stroke – but new research shows they may be linked with autoimmune diseases as well, Fox News reports.

A new study published in the journal Immunity indicates that people who have high blood levels of a molecule known to cause vascular diseases may also experience worsened symptoms of autoimmune disorders like psoriasis or arthritis.

The study focused on the molecule oxidized low-density lipoprotein (oxLDL), which, when elevated, is known to cause atherosclerosis – the hardening of arteries that can lead to heart attack or stroke. LDL is known to activate the immune system.

In a mouse study, researchers discovered that elevated levels of oxLDL caused mice with atherosclerosis to also experience an increase in Th17 cells, which resulted in worsened symptoms of autoimmune disorders. When they inhibited the activity of the Th17 cells, autoimmune symptoms improved.

"Our study suggests that we should consider circulatory factors in current therapeutic approaches for the treatment of autoimmune diseases," senior study author Yeonseok Chung, of the University of Texas Health Science Center at Houston says. "For instance, we expect that controlling oxLDL levels in circulation could greatly improve the therapeutic efficacy of immunological or pharmacological treatment of autoimmune diseases."