Women's weight gain from childhood to adulthood could influence ageing process

A new study has indicated that women who undergo substantial changes in BMI from childhood to adulthood show signs of accelerated ageing in their DNA.

Published in PLOS One this week, the research investigated stretches of DNA called telomeres, which are situated at the ends of chromosomes. Telomeres protect our genetic data and have been compared to the plastic tips of shoelaces because they prevent chromosomes from fraying or sticking to each other. Telomeres shorten over time and their length is thought to be a biological marker for ageing. Short telomeres are also linked to a higher risk of age-related disease such as type 2 diabetes and heart disease.

Previous research suggested that  high body mass index (BMI), high waist-to-hip ratio (WHR) and excess abdominal fat in adulthood are associated with shorter telomeres. There is also evidence that severely obese children have shorter telomeres. The researchers wanted to explore how this connection between obesity and telomere length developed into adulthood.

In a sample of 5,620 men and women born in Finland in 1966, the study confirmed the relationship between telomere length and measures of fatness and excess weight. Alongside this it also revealed a potentially important link between shorter telomere length and dramatic changes in BMI from childhood to adulthood in women.

“Our research demonstrates that telomere length is related to measures of excess weight,” said Professor Alexandra Blakemore from the Department of Medicine, Imperial College London, lead author on the study. “But even more interestingly it showed that it is not just the BMI itself that is linked to telomere length, but the increase in BMI as women become adults.  This suggests that if women put on more weight than expected they could suffer premature ageing and be at greater risk of age-related diseases. It also raises questions about the implications for women who change their weight dramatically and yo-yo between weight loss and weight gain. Currently we have little understanding around how this behaviour affects long-term health, but our research indicates that the study of telomere length could provide a window through which to investigate the impact of weight cycling on the ageing process and the risk of age-related diseases.”

The researchers examined telomere length in blood cells (leukocyte telomere length) collected when participants were 31 years old.  From the data on the 5,620 participants the researchers calculated the body mass index (BMI) and waist-to-hip ratio (WHR) at the age of 31. They also calculated BMI at the point in development where children start to put on weight after losing initial ‘baby fat’ during the active early childhood stage. This point, known as adiposity rebound (AR), is around six years.  

The results showed a clear link between shorter telomere length and increasing BMI and WHR in adults for both men and women. It also demonstrated that women who experience an unusually large increase in BMI as they grow and mature tend to have shorter telomeres, suggesting that this type of weight change from childhood to adulthood could be detrimental to health in terms of speeding up the ageing process.

“We now need to conduct further research to investigate the longer term implications of excess weight gain between childhood and adulthood,” said  first author on the study Dr Jess Buxton from the Department of Medicine, Imperial College London. “This could involve measuring the telomere length at other points during the lifecourse to see how this is related to later measures of weight and fatness. Then we could see how this relationship develops over time and possibly highlight important points in our lives when substantial weight gain or loss impacts the ageing process. It would also be interesting to compare the long-term effect of different weight loss strategies on telomere length.”

The research was funded by the Wellcome Trust. The research team included Dr Jessica Buxton, Dr Shikta Das and Professors Marjo-Ritta Jarvelin and Alexandra Blakemore.

Reference: Buxton et al. ‘Multiple measures of adiposity are associated with mean leukocyte telomere length in the Northern Finland Birth Cohort 1966’ PLOS One, 2014.