Varicose veins may be an early warning sign of potentially deadly blood clots, according to a study published on Tuesday in the journal JAMA.
Taiwanese researchers have found strong association between enlarged and gnarled varicose veins and deep venous thrombosis, a clot that forms in the deep veins of the body, are strongly associated.
Though they considered the health records of over 425,000 adults, the researchers say that even more work is needed to understand whether this relationship is one in which varicose veins directly cause blood clots or whether the two conditions simply have a similar origin.
"The most common question from a varicose vein patient in the vein clinic is: 'Will varicose vein bring any health risk for me?' " said Dr Shyueluen Chang, first author of the study and a phlebologist and dermatologist at Chang Gung Memorial Hospital in Taoyuan, Taiwan.
Chang said, for this reason, learning about potential relationships between "varicose veins and health-threatening diseases is important," CNN reported.
According to commentators, varicose veins, usually caused by pregnancy or the effects of age weakening the blood vessels, are common.
In the US, nearly a quarter (23 per cent) of adults suffer from the condition, which doctors rarely associate with serious health risks.
The researchers who studied data of over 425,000 people from Taiwan's National Health Insurance programme, found that varicose veins were associated with 5.3 times higher risk for deep vein thrombosis.
They also found a higher incidence of pulmonary embolisms (PE) and peripheral artery disease (PAT) in people with varicose veins but the associations were less clear due to potential confounding factors.
"Among adults diagnosed with varicose veins, there was a significantly increased risk of incident DVT; the findings for PE and PAD are less clear due to the potential for confounding," the researchers wrote in their study.