A spike in heart attacks in post-menopausal women is attributable to aging of heart and artery cells -- not menopause itself -- U.S. researchers say. Study leader Dhananjay Vaidya, an assistant professor of medicine at The Johns Hopkins University School of Medicine, said the findings could have implications for how heart health is assessed in pre-menopausal women, who were previously believed to be at negligible risk of death from heart attack. "Our data show there is no big shift toward higher fatal heart attack rates after menopause," Vaidya said in a statement. "What we believe is going on is that the cells of the heart and arteries are aging like every other tissue in the body, and that is why we see more and more heart attacks every year as women age. Aging itself is an adequate explanation and the arrival of menopause with its altered hormonal impact does not seem to play a role." Vaidya's team analyzed mortality statistics for people born in England, Wales and the United States from 1916 to 1945. They followed similar groups of people as they aged and found that, at the time of menopause in each group, there were no increases in female mortality rates above and beyond the steady curve that is expected from aging, the research team said. The study, published in the British Medical Journal, found the number of women who die each year from heart disease increases exponentially at roughly 8 percent per year.