The rate at which we age depends on socio-economic status and can be revealed by a DNA test, which will improve assessment of public health measures, say Glaswegian scientists.
The test measures the length of repetitive sections of DNA found at the end of chromosomes, known as telomeres. Every time a cell divides, these telomeres shorten. Scientists found that not only do your telomeres get shorter with age, the rate of shortening correlates with three factors: diet, household income and whether people are home owners or not. The findings confirm the results of pioneering work led by Professor Tim Spector at King's College London, published in 2006, which first associated faster telomere shortening with socio-economic status.
The latest study was carried out by the Glasgow Centre for Population Health, a consortium of health and local authorities, the Scottish Government and Glasgow University. It focused on Glasgow as it has one of the widest extremes of life expectancy between its most deprived and most affluent areas.
Dr Paul Shiels, from the Institute of Cancer Studies at Glasgow University, said: 'We show that accelerated ageing is associated with social status and deprivation in Glasgow. This is most prevalent in the over-55s and those with household incomes under £25,000. This effect is exacerbated by diet - simply not eating your five portions of fruit and veg a day'.
The researchers found that over ten years those with the poorest diets had 7.7 percent (%) shorter telomeres, while those with the best only had a shortening of 1.8%. Telomeres shortened by 7.7% in people with household incomes less than £25,000, compared with 0.6% in those earning above that, and by 8.7% in those living in rented houses compared with 2.2% in home owners.
Until now, public health improvement measures addressing the inequality in life expectancy have relied upon illness rates as an indication of success. This feedback can be slow and prone to error. It is hoped the finding that telomere shortening rates can be linked to three key assessment factors will provide faster feedback on public health interventions.
Although the test gives an accurate indication of ageing within a population, it does not determine the life expectancy of an individual, due to the natural differences in telomere length. Dr Shiels explained: 'Its value is at a population level, where large numbers of subjects allow us to observe trends over a period of time. It is a tool for looking at the impact of changes in diet, for example. This study is a first for Glasgow and indicates that socio-economic conditions do affect the rate at which you age'.
The results are published in the Public Library of Science (PLoS) journal.