What Causes Hernia to Occur and Reoccur?

Below are the risk factors that cause hernias and increases the chances of them reoccurring.

Being overweight

Chronic lung disease such as asthma and COPD

Increased age and frailty

Poorly controlled diabetes


Certain medications such as steroids and immunotherapy

These risks for hernia formation (including recurrence) work by deteriorating connective tissue quality and or increasing the forces applied to the abdominal wall.

To understand this, you need to understand the structure of collagen. Collagen is a structural protein that lies in parallel fibres. These parallel fibres could be forced apart by pressure applied to them. So, they have evolved (di-sulphide) cross-linking bridges that prevent the parallel fibres being forced apart and another protein woven into the parallel fibres called elastin that allows the collagen to stretch and recoil with pressure and movement. The mix of genes we have for expressing this individualizes the expression of our connective tissues so without additional risk factors we have a varying risk of abdominal wall hernias forming just from how our genes are expressed.

Some external risks alter this. Smoking reduces the amount of collagen we have in tissues (makes tissues thinner), with a lower proportion of elastin and far fewer di-sulphide bridges (so they are weaker) making it easier to push collagen fibres apart. Old age sees the same effect in slightly different proportions. So, as we age, we become more prone to hernias. Steroids reduce the amount of collagen we replace as our tissues are recycled. Smoking, older age and steroids weaken our connective tissues.

Poorly controlled respiratory disease and obesity work in the other way. By increasing the pressure/force applied to our abdominal wall. Whether you are more prone to developing an apple rather than a pear shape alters the mechanism, but the outcome is the same. Excess fat deposition occurs in and between all tissues this alone can weaken the connective tissue so increases the risk described above without altering the relative proportions of the structural proteins. Fatty tissue dilutes them a little if you like and fat has no strength.

Respiratory disease affects our risk as the top half of our abdominal wall is needed to aid respiration. It is why using your arms to brace yourself when short of breath helps your breathing. You are using your abdominal wall and shoulders to aid respiration. The more easily we become short of breath (poorly controlled respiratory disease) or the more obese someone is the more effort is required to lift that weight during breathing so muscles tire quicker and the fixed natural weak areas of the abdominal wall described below get pulled allowing the intra-abdominal content to exert more pressure or force against the weakest areas. This is how pear shapes develop hernias.

Apple shapes deposit fatty tissue inside their abdomen and this accumulating mass exerts increasing pressure against the abdominal wall. As this is countered by core muscle contraction with simple everyday activity such as walking or getting up and out of a bed or chair these muscles pull against the more fixed natural weak areas that can open up potential shapes to become actual spaces. The greater your intra-abdominal pressure the greater this effect. The more overweight we are the more we combine apple and pear shapes and so make these effects even greater.

Lastly, how does diabetic control alter the risk? This is more complex to explain. To keep it simple: poor glucose control over time alters the rate at which we replace tissue, making it ‘age’ quicker. The more normal our average blood sugars the less this happens.

Can you reduce the risk of a hernia occurring?

We have tried to describe the risks for forming hernias so you can use this information.

Some risks can be removed like smoking and perhaps obesity. Some can be modified – better respiratory disease control, losing weight, and some cannot such as ageing or medicine prescriptions and dosing. Moving to alternate medications and lowering the dose is the best you can do. You cannot stop yourself from aging, but maintaining strength through exercise classes and training will reduce the rate of connective tissue deterioration (use it or lose it!).

Many of these exist in combination. Smoking causes respiratory disease after we have been smoking for many years and getting a bit older. That is then treated with a steroid inhaler for example. Being obese may require respiratory support, again with similar drugs used to try and help as another example. This is the reason we try to stop people from smoking and recommending they lose excess weight prior to surgery. It reduces the symptoms and risks of your hernia and makes repair long lasting.

If you’d like to understand more about the healing process after hernia surgery with Hernia Clinic Hampshire read this


Remember you can only repair each of these hernias 2-3 times. It is important to give each attempt the best chance of success. At Hernia Clinic Hampshire this philosophy is key to the advice we offer and the reason we give this advice.


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