Compared with women who had their final menstrual period at age 55, for instance, those who finished menstruating at age 47 had a 6.3% greater 20-year cumulative fracture risk, the authors note.
While previous findings from the Malmo Perimenopausal Study showed menopause prior to the age of 47 to be associated with an 83% and 59% greater risk of densitometric osteoporosis and fracture, respectively, by age 77, the authors note that the new study is unique in including only women who had a final menstrual period over the age of 45, therefore reducing the potential confounding of data on women under 45.
The new results “add to a growing body of literature suggesting that the endocrine changes that occur during the menopause transition trigger a pathophysiologic cascade that leads to organ dysfunction,” the authors note.
In terms of implications in risk assessment, “future studies should examine whether years since the final menstrual period predicts major osteoporotic fractures and hip fractures, specifically, and, if so, whether replacing chronological age with years since the final menstrual period improves the performance of clinical prediction tools, such as FRAX [Fracture Risk Assessment Tool],” they add.
Addition to guidelines?
Commenting on the findings, Peter Ebeling, MD, the current president of the American Society of Bone and Mineral Research, noted that the study importantly “confirms what we had previously anticipated, that in women with menopause who are 45 years of age or older a lower age of final menstrual period is associated with lower spine and hip BMD and more fractures.”
“We had already known this for women with premature ovarian insufficiency or an early menopause, and this extends the observation to the vast majority of women – more than 90% – with a normal menopause age,” said Dr. Ebeling, professor of medicine at Monash Health, Monash University, in Melbourne.
Despite the known importance of the time since final menstrual period, guidelines still focus on age in terms of chronology, rather than biology, emphasizing the risk among women over 50, in general, rather than the time since the last menstrual period, he noted.
“There is an important difference [between those two], as shown by this study,” he said. “Guidelines could be easily adapted to reflect this.”
Specifically, the association between lower age of final menstrual period and lower spine and hip BMD and more fractures requires “more formal assessment to determine whether adding age of final menstrual period to existing fracture risk calculator tools, like FRAX, can improve absolute fracture risk prediction,” Dr. Ebeling noted.
The authors and Dr. Ebeling had no disclosures to report.