THE health of babies born in deprived areas could be damaged for the rest of their lives long before they have even left the womb, according to startling research from Scots scientists.
They have found stressful conditions experienced by expectant mothers in impoverished areas because of poor lifestyle choices could impact on their children’s DNA – leaving them with an increased chance of developing diabetes and cardiovascular disease later in life.
Genes were found to be affected within the first few weeks of an embryo’s development – meaning some mothers in deprived postcodes could be putting their children at harm without knowing they are pregnant.
Experts in epigenetics – which explores how someone’s environment and lifestyle choices can influence their genetic code, and that of their children – took blood samples from 239 people from the most deprived and the most affluent areas of Glasgow.
They believe factors experienced by expectant mothers in areas of deprivation cause “bugs” to develop in the DNA of embryos, with the children more susceptible to early onset of diseases when they become adults.
The team behind the groundbreaking study at Glasgow University said their findings offered the beginning of an explanation as to why Scotland’s biggest city has the unwanted title of “the sick man of Europe”.
Charities campaigning to tackle child poverty described the research as “startling evidence” of the impact poverty can have on children before they have even left the womb, and warned that cutbacks to welfare provision would only worsen the damage.
The researchers found significant differences in levels of “methylation” in the DNA of people from different ends of the socio-economic spectrum.
DNA methylation is a natural biochemical process which controls how genes work. The majority of this methylation content is fixed for life in humans from just a few weeks after conception as the structure of the body and organs is formed.
Enzymes in the body create chemical “tags” which are imprinted on to DNA to switch on or off 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. The tags are “read” by cells, similar to the way software’s binary code is processed by computers, and ensure each cell switches on or off only the genes it is supposed to in order to ensure the body works correctly and remains healthy.
However, lower levels of methylation can impair this process, increasing the chances of developing diabetes and cardiovascular disease later in life.
Research leader Dr Paul Shiels, senior lecturer in epigenetics at the university, said: “We found that 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 that the significantly lower levels of methylation we’re seeing in the most deprived areas of the city are set before birth.”
Professor Carol Tannahill, director of the Glasgow Centre for Population Health, which funded the research as part of an ongoing public health study known as pSoBid, said: “The association between deprivation and ill-health is well established, but the pathways through which deprivation leads to poorer health outcomes are less well understood. Previous findings from the study have confirmed that people with relatively low income, living in poor circumstances, have more miles on their biological clock than people of the same age in better circumstances.
“The new findings add evidence that people in poorer socio-economic circumstances may face an uphill health challenge from before birth.
“Health inequalities are a reflection of wider inequalities in society. We are now learning that these inequalities have direct epigenetic effects. If we are going to improve health in Scotland, we need to keep a focus on action to address poverty and regenerate poorer neighbourhoods, and to support all children to have a good start in life.”
NHS Greater Glasgow and Clyde’s director of public health, Dr Linda de Caestecker, said the research served to reaffirm its commitment to tackling poverty in the area, while a spokesman for Glasgow City Council said it was “very interested” in the study, and stressed that they recognised a range of “economic, cultural, and social factors” contributed to people’s health.
HOW IT WORKS
1 DNA methylation is a natural biochemical process where changes in the chemical make-up of the DNA switch off the genes that regulate cell growth or affect its behaviour.
2 Dr Paul Shiels, the leader of the research team, compared the process with the way a PC works. He said: “If you think of your chromosomes as the hard drive of a computer, and the methylation as a program, sometimes the program can be corrupted. If you have a poor program, then it’s not going to work as well.”
3 If not enough methylation is put on organs as they are forming, then, like a program, there can be a lot of bugs over a lifetime. Dr Shiels added: “There’s a drip effect, which predisposes you from birth to be less robust and therefore more prone to early-onset disease.”
4 Other factors that influence genetic make-up – such as diet, smoking and toxins – were examined, but the main factors were found to be psychological and sociological stress.