Why is it that around 20% of people in western societies are significantly affected by acne and other people are not? The biggest factor is almost certainly genetic. But could there be more to it?

It has been acknowledged for years that if you have a first degree relative (parent or sibling) with acne, then you have a much higher chance of suffering from it yourself. You share 50% of your genes with a first degree relative and most estimates are that if one or more is affected by acne then you will have roughly a one in two chance of getting it yourself. An even better way of looking at the genetic contribution to acne is to investigate monozygotic (identical) twins. A large study in Australia calculated that 80% of the likelihood of suffering from acne could be attributed to one’ genes with the other 20% attributable to environmental factors.

Some doctors think that this 80% genetic figure is a big exaggeration. They emphasise the significant rise in the prevalence of acne in western societies over recent years and sensibly point out that this is most likely to be due to environmental factors rather than genetic ones. Increased consumption of unhealthy “junk food” is often mentioned, and of course twins are likely to be brought up together and therefore to be eating similar diets as well as being exposed to other similar risk factors.

So, what might be inherited that puts people at greater risk of developing acne? Several factors have been suggested including hormonal influences, being overweight and having excess sebum production. In the Australian study, the only thing that emerged as commoner in affected than an unaffected twin was that of lower apolipoprotein levels in their blood. This protein is involved in processing cholesterol and so might be linked to sebum production.

In this context, it is again worth noting that people eating a healthy Mediterranean diet are less likely to suffer from acne, perhaps because this reduces cholesterol and therefore sebum production as well as maintaining a healthy weight.

What is the relevance of the genetic link to acne for people who have, or may develop the condition?

If you have a family member with acne, and you have not developed it, then it would be helpful to be vigilant so that help can be sought at an early stage. Also, if a family member has been treated successfully for acne, then this will give you a clue as to what might be helpful for you. It is also important to bear in mind that you can influence the course of the condition markedly through attention to lifestyle factors, especially diet, as detailed in blogs elsewhere on this site. A useful phrase to remember is

“Genetics loads the gun but it is the environment that pulls the trigger.”

DR SAM ROBSON  - TEMPLE MEDICAL CLINIC, ABERDEEN.
Dr Robson is LUSTRE® Expert Panel Member, and Medical Director of Temple Clinic in Aberdeen.