Asthma, a chronic lung condition that affects the airways, can occur in people of all ages. In some cases, asthma symptoms can be mild and are well controlled with asthma medications. For others, symptoms are more severe and can have a debilitating effect on daily life and work. Asthma and other atopic conditions can run in the family, meaning if you have a family history of the condition, you are more at risk to developing it.
There’s no cure for this bronchial condition, but it can be effectively managed with modern treatments, and research continues to reveal more about asthma causes.
Read on to discover if asthma is genetic or environmental and if there’s any truth in the idea that asthma can run in families.
Is asthma genetic?
It’s understandable to be curious about what causes asthma. It’s a complex disease and while the exact cause is still unknown, research has shown that both genetics and environmental factors are involved.
Children who have parents with asthma are more likely to have it themselves. If one parent has asthma, there’s a 25% chance their child will too. If both your parents have it, this risk rises to 50%.
The influence of genes is highlighted in twin studies, which have found that asthma is more likely to occur in people who have a genetically close relative with the condition. For identical twins, the likelihood of both twins having asthma is higher than non-identical twins. But it’s 75% likely rather than 100% guaranteed, highlighting that environmental factors play a role too.
Is there an asthma gene?
While asthma is genetic, environmental factors play a part too. Unlike other inherited conditions, there is no single gene for asthma. Neither is there a guarantee that you’ll develop it if your parents had it, as it can skip a generation. Genetic research has identified various asthma genes, or gene complexes, that play a strong role. These include DPP10, GRPA and SPINK5.
Genomics is the study of how your genes interact with the environment. Genomic research is ongoing and provides a valuable insight into the complexity of asthma and the various factors involved in its development. Environmental factors that can increase the risk of asthma occurring can be both indoor and outdoor. For example, being exposed to second-hand smoke, poor air quality, pollution, cold temperatures and high humidity can all increase your risk.
Research shows that a combination of several genes interacting with each other and with environmental factors can increase the likelihood of asthma.
Asthma genetic factors
Several genetic factors can predispose you to a greater risk of developing asthma.
These include:
- Your family history
- Your gender.
Asthma and family history
Numerous studies have found that your family history can be a risk factor for the development of asthma. If one of your parents or siblings has asthma, then you’re more likely to have it too. If both your parents have asthma, then this risk increases further. You’re also more likely to have other related atopic conditions, such as eczema, hay fever or food allergies.
This doesn’t mean that you’ll definitely develop asthma if other members of your family have it, just that the genetics predispose you to a greater risk. Nor does it mean that you won’t develop the condition if your relatives are all free of asthma.
Asthma and gender
Studies have found that asthma is more common in young boys, whereas girls are more likely to be affected after puberty. Some experts believe this could be due to boys’ airways being smaller than girls’ airways, increasing the risk of wheezing.
By the age of about 20, the ratio of asthma is the same in women and men. However, by the age of about 40, women are more likely to develop adult-onset asthma than men. There’s also some evidence to suggest women are more likely to have severe asthma than men.
Is hereditary asthma curable?
No forms of asthma, be it hereditary asthma or occupational asthma caused by exposure to fumes, dust or other substances through your work, are fully curable. However, there are a number of effective medications and lifestyle measures that can be used to successfully manage and treat your symptoms.
Your doctor or asthma nurse will work with you to create an asthma treatment plan that suits you. This tailored approach works well, as no two cases of asthma are identical and it can affect people in different ways.
Modern treatments for asthma focus on trying to relieve symptoms and stop them from happening. Asthma inhalers are commonly prescribed for this. A reliever inhaler (normally blue) can be used to ease asthma symptoms that occur, whereas a preventer inhaler (normally brown) is prescribed to prevent the symptoms occurring. In some cases, you may be prescribed an inhaler that does both, known as a combination inhaler.
Your doctor will provide advice on how and when to take your inhalers. A brown inhaler is typically used on a daily basis, whereas you may only need to use a blue inhaler sporadically, especially as your asthma symptoms become better managed.
Sometimes tablets are prescribed, especially if inhalers alone aren’t fully controlling your symptoms.
There are also practical lifestyle steps that you can take, in conjunction with using your inhalers and taking medication as guided by your doctor.
These include:
- Exercising regularly – once your asthma is under control, regular exercise is beneficial
- Eating healthily – a balanced diet with plenty of fresh fruit and vegetables is advised; being overweight can exacerbate asthma
- Not smoking – smoking is a known irritant and stopping smoking can reduce the frequency and severity of your symptoms.
As for the future, it’s possible that increased genetic knowledge and research could lead to the development of even more personalised medicine and pharmacogenetics for asthma. This means that asthma treatments could be better tailored to you as an individual, and that your genetic information could be used to predict in advance how you’ll respond to certain treatments.