How tall you are might play a part in whether you are unlucky enough to develop varicose veins, a new study suggests.
Every additional four inches (10 cm) in height increases your risk of varicose veins by about 25%, said researcher Dr Erik Ingelsson, a professor of cardiovascular medicine with Stanford University School of Medicine.
"We have pretty robust evidence that height is actually causally related through genetics with increased risk of having varicose veins," Dr Ingelsson said, though the study did not definitively prove causality.
Varicose veins are swollen, twisted, gnarled veins that can be seen just below the surface of the skin. They are often dark purple or blue in colour, and most frequently appear on the legs.
Varicose veins do not increase a person's risk for heart attack or stroke, explained cardiologist Dr Nieca Goldberg, medical director of NYU Langone's Joan H. Tisch Center for Women's Health.
"They're generally a benign condition," said Goldberg, a spokeswoman for the American Heart Association.
But these veins can become achy, itchy or painful, and can contribute to swelling of the legs due to fluid retention, she added.
Varicose veins affect up to 25% of women and 15% of men, according to the Vascular Disease Foundation.
How do varicose veins develop? Veins are designed to quickly shoot blood back up to the heart, with one-way valves that encourage blood flow, Goldberg said.
When these one-way valves start to fail, blood can start pooling the veins, causing them to swell and stretching the vein walls.
It's been known that there are genetic factors involved in development of varicose veins, Ingelsson said. A family history of varicose veins makes it more likely you'll develop them as well.
To explore potential risk factors for varicose veins, researchers analysed the health of more than 413 000 people aged 40 to 69 across the United Kingdom. This included a screen of genetic markers for more than 337 000 of those participants, including nearly 9 600 with varicose veins.
Researchers confirmed a series of known risk factors, including age, gender, obesity, pregnancy and history of deep vein thrombosis.
But when they sorted people by height, they found that those in the tallest quarter of folks were 74% more likely to develop varicose veins than the shortest quarter of people.
Further, the researchers linked genes that determine a person's height to their risk for varicose veins.
The researchers also found a strong genetic correlation between deep vein thrombosis and varicose veins.
It's possible that height puts additional strain on veins trying to return blood to the heart, Ingelsson said.
"If you're taller, you have higher pressure downwards on your veins," he said. "The veins are pushing the blood back up to the heart. If you're tall, that creates more pressure."
Reducing the risk
Tall people can help reduce their risk of varicose veins by wearing compression socks, especially if they spend a lot of time on their feet, Goldberg said.
Varicose veins that have become very unsightly or uncomfortable can be safely removed through laser surgery, she added.
"In cases where these veins are irritated, itching, infected or contributing to swelling, you really should see a vascular specialist because you may be a candidate for a vein procedure to help eliminate the varicose veins," Goldberg said.
The study was published in the journal Circulation.
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