What Causes Varicose Veins?

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What causes varicose veins?

Varicose veins are the most common visible sign of chronic venous disease (CVD), a health issue that can be seen in about 39% of Australians. [1]

Although this condition can affect anyone, it’s much more common in women and older adults.

But what causes varicose veins, exactly? Is it just a matter of age and gender?

In this article, we will explore what varicose veins are, how they develop, and why it’s so important to understand their possible causes.

Varicose Veins in a Nutshell: What Are They and Who’s at Risk?

Varicose veins are enlarged, twisted veins. They are easy to spot as greenish, bluish, or purplish blood vessels just beneath the skin. Although any vein in the body can become varicose, the legs are their most common localization, especially the calves.

Over time, varicose veins bring growing discomfort and fatigue. In some cases, they can even lead to local wounds, also called varicose ulcers or venous stasis ulcers. They develop when the veins don’t circulate the blood back to the heart, keeping it pooled for a long time.

Varicose veins can affect people of all genders and ages, but they are more common in women and older individuals. Here are a few examples to illustrate this:

One study with over 2,000 participants reported that varicose veins were found in 50.5% of women compared to 30.1% of men. [2]
In their 30s, about 3% of men and 20% of women experience varicose veins. This rate increases to nearly 40% and 50% respectively in men and women over 70 years. [3]

So, gender and age are definitely the top two risk factors to remember when thinking about what causes varicose veins. However, the list doesn’t end there. Having a deeper understanding of the issue helps to choose the most effective approach to the management of varicose veins.

Let’s go back to square one: anatomy.

The Anatomy of Healthy Veins vs. Varicose Veins

To understand what causes varicose veins, the best approach is to go through a quick review of how the human circulatory system works in the first place. 

So, our circulatory system consists of three components: the heart, the blood, and the blood vessels (arteries, veins, capillaries).

Arteries carry oxygen-rich blood from the heart to the organs and systems in the body. Veins carry blood that’s oxygen-poor (and rich in carbon dioxide) back to the heart.

Veins have thinner walls, with a thinner layer of smooth muscle tissue. Arteries are much thicker, with a thicker layer of muscle in their walls.

However, the main anatomical difference between arteries and veins is that veins have one-way valves that prevent blood from flowing backward. These valves play a crucial role in maintaining healthy blood circulation.

Normal Vein Function: One-Way Traffic to the Heart

Let’s compare how vein valves work in healthy compared to varicose veins.

Image credit: https://en.wikipedia.org/wiki/Varicose_veins#/media/File:Varicose_veins-en.svg

Normal veins allow the blood to flow only in one direction, which is towards the heart. Whenever the blood tries to flow in the opposite direction, the vein valves close automatically. This ensures that the movement is always unidirectional, meaning one-way.

But what keeps the blood in your veins moving in the first place?

The two main factors are muscle contractions and vein elasticity. Whenever you move your legs, the muscles in them work as pumps that squeeze the veins and send the blood inside them back to the heart.

Compared to arteries, veins are much thinner and less elastic. This feature allows them to be excellent ‘blood storages.’ At any given time, up to ¾ of all your blood (that’s a whopping 75%!) is distributed throughout your veins. [4]

That’s why keeping the blood flow in the veins unidirectional is so important. Otherwise, these blood reservoirs can get enlarged and store even more blood than they usually do!

Here’s a simplified breakdown of how this process goes, step by step:

The vein valves malfunction and fail to keep the blood flow unidirectional.
When the muscles pump out the blood from your veins, part of that blood leaks back through the malfunctioning valves.
With each cycle, more and more blood gets pooled in the veins, stretching them from the inside.
Due to the increasing vein distortion, the vein valves work worse and worse with time.

When your doctor thinks through what causes varicose veins in general, according to the process described above, they compare that to your specific situation. This helps to identify risk factors and come up with a personalized strategy to help you.


What causes varicose veins

Risk Factors for Varicose Veins

What causes varicose veins in some people won’t necessarily lead to this condition in others. There are many elements at play, like pieces of a complex medical puzzle. Some of the most common factors that can increase your risk of developing varicose veins include:

Family History (Genetic Predisposition)
If venous issues in general and varicose veins specifically run in your family, this may also be what causes varicose veins, providing you with a risk of developing these conditions too. This may be caused by anomalies in the vein wall or vein valve structure.

But even if your veins and vein valves are healthy…

Did you know that just being tall already increases your risk of developing varicose veins?

According to studies, people in the highest quartile in terms of height (meaning those higher than 75% of other people) are 1.74 times more likely to develop varicose veins than people in the lowest quartile (those who’re shorter than 75% of other people). Ouch! [5]

This is because the blood has to travel a longer distance upwards against gravity in high people, meaning the pressure in their veins is higher than in short people. This pressure may deform the veins from the inside.

What causes varicose veins as we age? There are many factors at play here, but the core of the issue is that our veins get less elastic as we grow old. They become more likely to stretch or twist under pressure, pooling more blood and leading to varicose veins.

Hormones and Hormonal Changes
When considering what causes varicose veins in a specific case, hormones are always a major suspect. Female hormones (estrogens) play a crucial part in this, as they make the veins more prone to swelling and twisting.

Studies reported that there’s a correlation between blood levels of estradiol (one of the main female hormones) and venous swelling. The more estrogen receptors a person has in their vein walls, the more severe their varicose issue may get. [6]

Pregnancy and Childbirth
During pregnancy, the enlarged belly presses down on the veins in a woman’s pelvis, altering blood flow. The increased blood volume during pregnancy also ramps up the pressure inside the veins, making them more prone to varicose deformation.

Obesity and Other Lifestyle Factors
Carrying excess weight puts extra strain on the veins, making them more prone to venous insufficiency and varicose deformation. That’s why excess weight is always among the first factors to rule out when looking for what causes varicose veins.

Another lifestyle factor that puts you at a higher risk of developing varicose veins is smoking and vaping. Both habits damage the inner lining of the veins (the endothelium) and make it more prone to deforming.

Prolonged Sitting or Standing
Any job that involves long periods of sitting or standing can be what causes varicose veins. Do your best to move from time to time, even if it’s just a few steps every half an hour!

History of Blood Clots
Blood clots may damage the vein valves and lead to chronic venous insufficiency and varicose veins.

Primary Causes of Varicose Veins

Alright, now that we’ve gone through the most common risk factors. What causes varicose veins directly? What’s the immediate trigger that sets off the whole process? 

The most common ones include venous insufficiency, weakened vein walls, valve dysfunction, and venous reflux.

Venous Insufficiency

Venous insufficiency is the general name for when the veins in your legs struggle to return the blood back to your heart. As a result, more blood is pooled in them, stretching and distorting the veins.

Weakened Vein Walls

Over time, vein walls can weaken and lose their elasticity. The less elastic your vein walls are, the more likely they become to twist, stretch, and bulge.

Valve Dysfunction

If the one-way valves in your veins start malfunctioning, blood can flow backward and pool in the veins. After some time, this leads to varicose veins.

Venous Reflux

Venous reflux is the backward flow of blood in the veins, usually due to issues in the vein valves or vein walls.

These four factors combine like pieces of the same puzzle, promoting each other and leading to varicose veins in the long run.

Secondary Causes of Varicose Veins

Besides the primary causes mentioned above, there are a few secondary causes of varicose veins that are also worth mentioning in the discussion of what causes varicose veins.

Deep Vein Thrombosis (DVT)

In a nutshell, DVT is the formation of blood clots (thrombosis) in the deep veins of your legs. This damages the vein valves in them and leads to blood flow issues overall, even in your superficial veins. Studies reported that even after being resolved, DVT is a major cause of chronic venous insufficiency. What’s even worse is that subclinical DVT is often not visible on ultrasound. [6]

Pelvic Congestion Syndrome (PCS)

PCS is one of the leading causes of chronic pelvic pain in women, unrelated to pregnancy or menstruation. This complex condition is usually caused by enlarged veins in the pelvic area and can be what causes varicose veins in the thighs, buttocks, or even the vaginal area.

Tumors and Vascular Malformations

Tumors or vascular malformations can put pressure on the veins, impair the blood flow inside them, and lead to varicose veins in the long run. This is one of the rarest causes of varicose veins, but it’s still important to keep it in mind.

Symptoms of Varicose Veins

The most common symptoms of varicose veins include:

  1. Pain and discomfort. You may feel aching, throbbing, or burning in the legs.
  2. Visible bulging veins. Swollen and twisted veins are visible just beneath the skin. 
  3. Swelling, heaviness, and fatigue in the legs. Your legs may feel heavy or exhausted, especially after long periods of standing or sitting.
  4. Skin changes and ulcers. The skin near varicose veins can become discolored, dry, or prone to wounding.

Now that you know what causes varicose veins, what are the risk factors for developing them, and their most common symptoms, let’s go through the diagnosis process that your doctor will likely lead you through.

Diagnosis: How Your Doctor Spots Varicose Veins

Typically, varicose veins are easy to spot, but the final diagnosis should always be conducted by a healthcare professional. To answer the question of what causes varicose veins in your case, your doctor may recommend additional tests. 

Physical Examination: Your doctor will examine your legs, as well as ask about your symptoms, family history, and medical history.

Ultrasound Imaging: Ultrasound allows your doctor to visualize the vein walls and valves, making it one of the best tests to confirm or cross out venous insufficiency.

Venous Doppler Study: This is a special ultrasound technique that allows the doctor to visualize the flow of blood in the veins. In a nutshell, it shows if the blood flow is steady and one-way or turbulent, with backflow.

Prevention and Lifestyle Changes

Now that you know what causes varicose veins in general, let’s go through the most effective ways to prevent this condition or slow down its development. 

    • Maintaining a healthy weight. This is important to prevent excess strain on your veins.
    • Exercising and moving. The muscles in your legs work as pumps, preventing blood from building up in your veins. 
  • Elevating the legs regularly. From time to time, lay on your back and lift your legs. This will help to lead the blood that has been pooled in your legs back to your heart.
  • Avoiding prolonged sitting or standing. If your job involves long periods of sitting or standing, do your best to take regular breaks and move around for a while.
  • Wearing compression stockings. It’s better to discuss this point with your doctor because compression stockings come in different forms and compression levels. 

Besides these lifestyle changes, there are a few dietary recommendations worth keeping in mind. Avoid eating too much salty food, as it leads to water retention and may worsen symptoms of venous insufficiency. 

Another thing to watch out for is constipation. Chronic or frequent constipation is a known risk factor for developing hemorrhoids and varicose veins. The best natural way to prevent or reduce constipation is to keep an eye on your fibre intake. Eat more avocados, apples, carrots, beets, pears, raspberries, and other vegetables and fruit. Whole-grain foods are another great source of fibre to focus on.

As you see, answering the question of what causes varicose veins is a long and bumpy road. There are many lifestyle factors, hormonal changes, and even concurrent conditions to consider and cross out. The best way to approach the matter is to work together with an experienced phlebologist—a doctor who specializes in veins!

Book a consultation with our team today, and we’ll design a personalized treatment plan for you. Regardless of what causes varicose veins in your case, we have a wide arsenal of targeted treatments for any and all vein conditions!

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