I mentioned the recent linking of psychological stress and shortened telomeres, but Randall Parker has a lot more information at FuturePundit. In particular, other ways in which short telomeres have been linked to aging and health risks:
For those of you asking "What are telomeres and why are they important?" here is the short version: Telomeres are caps on the ends of chromosomes. They are made up of a very simple repeating sequence of DNA. Every time a cell divides its telomere gets shortened. Eventually the telomere gets so short that somehow as a result the cell can no longer divide or can divide only slowly and with increasing genetic damage.
My guess on the study reported above is that the mechanism of telomere shortening the researchers are observing is that stress causes certain classes of cells to divide more rapidly. Keep in mind that not all cells divide. For example, most nerve and heart cells are what are called post-mitotic. They no longer go through mitotic cell division. But skin cells and the various types of adult stem cells divide. One major cause of aging is that adult stem cell reservoirs throughout the body go through so many divisions that their telomeres get too short and they can't divide very well to provide cells to do repair.
Evidence has previously been found linking telomere length to mortality risk. The length of telomeres in endothelial progenitor cells (a type of adult stem cell) is linked to increased risk of cardiovascular disease. So those cells would be logical candidates to check for telomere length in women who have been under sustained stress.
Also, see an earlier thread here for good commentary on telomeres and the prospects for making them longer in a safe, reliable fashion.