FINANCIAL stress can cause some people to have more migraines.

This is if those people have a specific variation of the clock gene, according to the work presented at the European College of Neuropsychopharmacology conference now under way in Paris.

The work, according to a release, is the first time the genetics of circadian rhythms been shown to have an effect on migraine.

Migraine is a serious and debilitating neurological disease affecting one billion people worldwide, the release said.

Migraines have been estimated to cause around €27 billion every year in the European Union, and US$17 billion every year in the USA. In the UK, one in four women and one in 12 men are migraine sufferers, the release continued.

The background of migraines is highly complex, according to the release, involving a large number of genes and their interaction with environmental effects, and acting via multiple pathways in the central nervous system. Variations of circadian genes (which affect how the body controls and responds to environmental changes — such as changes in light) have previously been shown to affect mood disorders, so it was thought it would be interesting to see if they were associated with migraines.

The group of researchers from Hungary and the United Kingdom checked 999 patients from Budapest and 1,350 from Manchester for two variants (single nucleotide polymorphisms) of the Clock gene, and how these are associated with migraine. The Clock gene has an important role in regulating many rhythmic patterns of the body, including body temperature or level of cortisol — the primary stress hormone.

They found that there was no significant direct connection between the gene and migraines, but when they factored in stress (financial stress, measured by a financial questionnaire), they showed that the investigated gene variants increased the odds of having migraine-type headaches in those subjects who suffered from financial hardship by around 20 per cent, the release said.

According to the release, the researchers looked at functional, single nucleotide polymorphisms within the clock gene that are able to influence how much protein is transcribed from the gene. Because this protein controls the body clock machinery, these variants may impair processes that can prevent migraines in the face of stress.

Researcher Daniel Baksa of Semmelweis University, Budapest said: “This work does not show what causes migraine — there is no single cause — but it does show that both stress and genetics have an effect.

“In the work presented here, we were able to show that stress — represented by financial hardship — led to an increase in migraine in those who have a particular gene variant. What we need to do now is to see if other circadian gene variants in association with different stress factors cause the same effect,” Baksa said.

The researcher continued: “The strength of our study is that we saw the same effect in two independent study groups, in Budapest and Manchester, so we think it is a real effect. The investigated gene variants are present in around 1/3 of the population, so they are common variants with small, effect size.

“Our results shed light on one specific mechanism that may contribute to migraine. What it does mean is that for many people, the stress caused by financial worries can physically affect you,” Baksa said.

Commenting, Professor Andreas Reif of the University Hospital Frankfurt said: “This is a really interesting study on the interaction of genetics with stress in migraine. The studied gene is involved in the circadian system, which has previously been shown to be implicated in mental disorders such as bipolar disorder which, intriguingly, is co-morbid with migraine.

“Thus, this study might provide a clue how these diseases might be linked on the genetic level, which is interesting as such. But even beyond this, the study demonstrates how an environmental risk factor exerts its effect only in the presence of a given genetic risk factor. This has not been done to a great extent in migraine, making this study an exciting new lead,” Reif said.