London, Feb 14 (IANS) Hormone replacement therapy (HRT) could slow the ageing process and delay Alzheimer's for millions of women, suggests a new study.
The HRT is prescribed for menopausal women who cross 50 years to mitigate hot flushes and mood changes they experiencea as they age, although it also protects bones.
About one in five women carries a gene called Apo-E4 that acclerates ageing, increasing their susceptiblity to dementia. But HRT appears to protect the DNA and effectively slows down ageing, say the researchers, the Telegraph reports.
Natalie Rasgon of Stanford University School of Medicine in California said: "This shows that (the gene) is contributing to ageing at the cellular level well before any outward symptoms of decline become apparent. Yet oestrogen appears to have a protective effect for middle-aged women who are carrying this genetic risk factor."
About a million women discontinued HRT following a 2002 scare that it raised the risk of cancer. Doctors warn that using the treatment for long periods can increase the risk of breast cancer.
The study, which involved 70 healthy women aged 45 to 65 years, did not follow them long enough to find out which ones developed Alzheimer's. But over a two-year period it looked at changes in their cells that denoted ageing.
Researchers looked for changes in the length of what are known as telomeres, which are repeated sequences of DNA that "cap" the end of chromosomes.
They act rather like the plastic caps on shoelaces - protecting genetic material from damage. Telomeres shorten over the years, and scientists regard their length as a good measure of biological age.