To everything, there is a season

Posted by Liz on May 16, 2011 in menopause | 1 comment

[youtube=http://www.youtube.com/watch?v=W4ga_M5Zdn4]

We know that certain aspects of the menopause, in particular hot flashes can be influenced by weather. But did you know that menopause onset may also be seasonal?

In my weekly scan of the news, I ran across an older but interesting study that had been published in Maturitas in 2005. In it, researchers discuss how human reproduction is seasonal in order to optimize fertility and tends to correlate to the most favourable environmental conditions, including light and temperature. This fact led them to evaluate the medical records of over 2,400 white women who had attended outpatient menopause services in order to determine if entering menopause is also a seasonal phenomenon. The following were taken into account:

• Age
• Race
• Education
• Weight/BMI
• Smoking history
• Major illnesses that may have required surgery or chemo
• Number of pregnancies
• Type of menopause, last menstrual period, years since menopause
• Use of hormones
• Occupation

On average, the majority of women were 52, had been in menopause for 2 years, weighed about 143 pounds and were right on the BMI cut off of normal and overweight. Amongst this group of women, onset of menopause occurred significantly more often in winter than in spring, summer or autumn, respectively (although a minor peak in onset of menopause was also observed in smaller numbers of women during summer). When the researchers compared this timing to reproduction, they found that it was concentrated between the highest and lowest points of reproduction. Moreover, none of the other factors appeared to influence this seasonal variance of menopause onset.

However, like all studies, there are limitations, such as the fact that the women were of one race and were evaluated retrospectively. Or, that only two other studies have had similar findings and both of these were in monkeys. Still, it is rather interesting and I’d love to take a poll with those of you readers who have fully entered menopause and whose period has stopped for at least 12 months. If you are willing, leave a comment as to which season your menopause started. Meanwhile, the intrigue remains: is menopause a seasonal phenomenon and are there factors other than environment that influence its start?