Discussion: What is the Association of Menstrual Cycle Regularity and Length With Cardiovascular Disease?

In this video, Michael J. Bloch, MD, discusses the implications of a recently published study on the association of menstrual cycle regularity and length with cardiovascular diseases, including gaps in the research on this topic. This is part 2 of a 3-part discussion series on oral contraceptives in women and cardiovascular disease.

Additional Resource:

• Huang C, Lin B, Yuan Y, et al. Associations of menstrual cycle regularity and length with cardiovascular diseases: a prospective study from UK Biobank. J Am Heart Assoc. 2023;12(11):e029020. doi:10.1161/JAHA.122.029020

For part 1 of this 3-part series, visit here.

For part 3 of this 3-part series, visit here.

Michael J. Bloch, MD, is an associate professor at the University of Nevada School of Medicine, the medical director of vascular care at the Renown Institute for Heart and Vascular Health, and the President of Blue Spruce Medical Consultants, PLLC (Reno, NV).

TRANSCRIPTION: 

Dr Michael J. Bloch: Hello. My name is Dr Michael Bloch. I'm a vascular medicine provider from Reno, Nevada. I wanted to just delve into what I think is a very interesting recent report that came out of the UK Biobank and was published in the Journal of American Heart Association that looked at the association between menstrual cycle regularity and the subsequent risk of cardiovascular disease. This is obviously a very important topic. Cardiovascular disease is the leading cause of death and morbidity for women worldwide, and it has been increasing in prevalence. And really understanding what happens across a woman's premenopausal life and how that affects subsequent cardiovascular risk postmenopausally, I think, is something that has been understudied and is really clinically important.

So, as I mentioned, this data comes out of the UK Biobank. The UK Biobank is a very well-established prospective cohort of over 500,000 participants, aged 40 to 69, recruited across the United Kingdom between 2006 and 2010.

Participants who were included completed a touchscreen questionnaire including information on sociodemographic data, lifestyle factors, medication history, and medication use. They also had a brief physical assessment that included height weight, BMI, ascertainment of vital signs, and they provided some biological samples for some very simple laboratory studies. Participants were then followed for the development of incident diagnoses, in this case, cardiovascular events through national health records in the National Health Service. So at baseline, all female participants were asked to report on their current menstrual cycle length and regularity, and this particular study looked at those women who had not yet reached menopause at baseline and who reported menstrual cycle length in information and who had not yet had a cardiovascular event. For the purposes of this study, menstrual cycle irregularity was defined as one of the following, either a self-report of irregular cycles, a cycle length of less than 21 days, or a cycle length of greater or equal to 35 days.

A regular menstrual cycle was defined as a cycle length of 22 to 34 days. So these patients in this particular study, there were 58,000 women who had no cardiovascular disease at baseline and who had reported their menstrual cycle regularity and length. After 12 years of follow up the incidents of cardiovascular events was about 3.5% in women who had a history of irregular menstrual cycles as compared to about 2.5% in women who had a history of regular menstrual cycles. So that's a difference of nearly 20%. Very low absolute rates, but nearly a 20% difference. Interestingly, it did appear that the association between irregular menstrual cycle and atrial fibrillation was the strongest of the cardiovascular events that were studied. So it was a much a stronger relationship than was for stroke or MI or for heart failure. One of the things that I think makes this study a little bit difficult to interpret is that women who did have a history of irregular menstrual cycles did have a higher prevalence of other cardiovascular risk factors of baseline, so they higher prevalence of smoking, higher prevalence of hypertension and dyslipidemia and diabetes.

However, even in multivariate analysis, once those baseline characteristics were accounted for, it did still seem like that association held and that women with a history of irregular menstrual cycles still did have a higher incidents of subsequent cardiovascular events. So a very interesting clinical trial. I'll go into a little bit more of the implications of this data in a subsequent post.

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