Tuesday, August 2, 2016

Late Menarche, Late Menopause and Longer Reproductive lifespan linked to increased longevity.

Clinical Pearls:

  • Women who had menarche at age 12 or more and experienced menopause at age 50 or beyond have increased odds of living up to age 90 as compared to women who have early menarche and early menopause.
  • Those women whose reproductive life span lasted 40 years, were 13% more likely to celebrate 90 birthdays than women who were in reproductive period for 33 years. (odds ratio [OR]= 1.13).

A new study by researchers at University of California, San Diego found an interesting correlation between the age at menarche and menopause and longevity. Women who enter the reproductive period late and also have a late menopause are more likely to live till age 90.

The research implicated that women who had menarche at age 12 or more and experienced menopause at age 50 or beyond have increased odds of living up to age 90. 

According to Dr Aladdin Shadyab, of the University of California, San Diego School of Medicine "People have always wondered whether the timing of reproductive events affect longevity, but no study to date has evaluated that relationship."

The study was published in recent issue of Menopause, the journal of North American Menopause Society. [1]

The research team used data for Women’s Health Initiative study (WHI). The Women's Health Initiative (WHI) is a long-term national health study that recruited women from 1993 to 1998 and followed them until 2014 focusing on strategies for preventing chronic health diseases in postmenopausal women. This multi-million dollar, ground-breaking study has far reaching implications and have provided the health care providers with practical information to prevent and treat some of the major diseases impacting postmenopausal women. [2]

The study participants included 16,251 women from diverse racial and ethnic background all born before August, 1924. Multivariable logistic regression models were used to determine the association, adjustments were made of demographics, reproductive history and lifestyle of the women.

The average age of the study participants was 74. 7 years and 8,892 (55%) of the women lived through age 90.

As compared to those women who had an early menarche before age 12, those women who were at-least 12 or older at menarche have a 9% increased chances of living upto age 90. (odds ratio [OR]= 1.09).

Similarly, women who were at least 50 at the time of last period are 20% more likely to live till 90, as compared to women who stopped menstruating before age 50. The same was true for women who underwent surgical menopause. (odds ratio [OR]= 1.19).

Longevity was also tied to a longer reproductive life span. Those women whose reproductive life span lasted 40 years, were 13% more likely to celebrate 90 birthdays than women who were in reproductive period for 33 years. (odds ratio [OR]= 1.13).

The authors of the study cannot pinpoint a single reason behind this association, but multiple factors come into play.

Early menarche is often associated with obesity, Diabetes and CVD while early menopause is also linked to increased risk of CVD. These associated co-morbidities in women experiencing early menopause may be responsible for shorter life span.

Genome-wide association study of age at natural menopause identified genetic variants involved in DNA replication and repair pathways which is crucial in aging. Thus genetics is also an important factor.

The study has limitations of not knowing the longevity of the parents and other family members of the participants along with the work history and stress, which plays an important role in deciding longevity.

One other study published this week in Proceedings of the National Academy of Sciences and Biological Psychiatry, has shown that women with early menopause suffer from insomnia which accelerates aging and shortening the life span.[3]

The last decade has seen rapid improvement in life expectancy of older women adding average of 7 years to their life expectancy as compared to men[4] with a current total population of 1.3million women over the age of 90+.  Women surviving into their 90s outnumber men by a ratio of almost three to one.[5]

The authors conclude "With secular trends showing decreasing age at menarche, increasing age at menopause, and a concurrent rise in longevity, additional studies in younger birth cohorts will be needed in the future to precisely define the relationship between the timing of reproductive events and a woman's length of life."




[1]http://journals.lww.com/menopausejournal/Abstract/publishahead/Ages_at_menarche_and_menopause_and_reproductive.97952.aspx
[2] https://www.whi.org/about/SitePages/About%20WHI.aspx
[3] http://newsroom.ucla.edu/releases/menopause-sleepless-nights-may-make-women-age-faster
[4] http://www.census.gov/prod/2011pubs/acs-17.pdf
[5] https://www.census.gov/newsroom/releases/archives/aging_population/cb11-194.html

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