THE health of the most deprived residents of Scotland's biggest city could be impaired even before they are born, according to genetic research.

The study by scientists at Glasgow University, which sheds fresh light on the city's poor health record, found that higher rates of illness could be predetermined through the make-up of residents' DNA.

The differences in their DNA mean they have a higher chance of developing diabetes and cardiovascular problems in later life when compared with people who live in more affluent areas.

Research leader Dr Paul Shiels, a senior lecturer in epigenetics at Glasgow University, said it was a "significant" discovery which might explain why the health of people in Glasgow is much worse than in other European cities.

In the study, researchers identified significant variations in a process known as methylation between DNA samples taken from people living in the most affluent and most deprived areas of Glasgow.

The majority of methylation content is fixed for life from just a few weeks after conception as the structure of the body and organs are formed, but lower levels are known to increase a person's chances of developing diabetes and cardiovascular problems later in life.

Both of these conditions are disproportionately high in Glasgow.

A team from the university's College of Medical, Veterinary and Life Sciences and the Glasgow Centre for Population Health examined blood samples of 239 individuals living in the city, comparing levels of DNA methylation.

Dr Shiels said: "We found levels of DNA methylation were significantly lower in the samples from the most deprived areas than they were in those from the least deprived, and those samples also showed signs of an elevated risk of cardiovascular disease.

"Methylation levels decline throughout everyone's life as part of the natural process of ageing, and can be slightly affected in adulthood by external factors such as diet, stress and lifestyle.

"Those external factors have a much greater effect on babies developing in the womb, affecting the enzymes which allow DNA methylation to occur, so it's very likely the significantly lower levels of methylation we're seeing in the most deprived areas of the city are set before birth.

"It's a significant finding and may provide part of the explanation as to why many Glaswegians suffer such poor health in comparison to people in other cities in the UK and across Europe. Further study is required, and we are undertaking other work in this field at the moment, but practical outcomes from this research could include much quicker feedback on the effectiveness of public health interventions or the development of tests to identify individuals whose levels of DNA methylation suggest they are more at risk of developing health problems."

Methylation occurs as enzymes in the body create chemical "tags" which are imprinted onto DNA to switch on or off the expression of genes at the right time and in the right place. Most of these tags stay in place for the rest of an individual's life.

These tags are then read by cells, similar to the way software's binary code is processed by computers, and ensure that each cell expresses only the genes it is supposed to in order to ensure the body works correctly and remains healthy. Lower levels of methylation can impair this process, increasing the chances of a person eventually developing diabetes and cardiovascular disease.

A study commissioned last year by the Scottish Government highlighted a "Glasgow effect" which appeared to place residents in the city at a heightened risk of heart attacks and anxiety compared to people with similar lifestyles and socio-economic backgrounds in other regions.

Dr Shiels hopes the team's work may help to unravel part of the Glasgow health riddle.

The study, published in the International Journal of Epidemiology, was funded by the Glasgow Centre for Population Health and is part of an ongoing project, called pSoBid, which is investigating the psychological, behavioural and biological determinants of ill-health in the city.