Middle-aged women who have lower levels of oestrogen and progesterone are more likely to snore, breathe irregularly and gasp while sleeping, which are all symptoms of sleep apnoea.
The involvement of these chemicals means targeted hormone therapy might prove useful for post-menopausal women, says Kai Triebner at the University of Bergen in Norway.
“Women live, on average, longer than men, but during later years, the quality of women’s life is comparatively low, which is inherently associated with their [low-oestrogen] hormone profile,” says Triebner. “Snoring and sleep-related breathing problems add to the burden.”
Researchers have long suspected that sleep apnoea is related to menopause, when hormone levels drop and periods cease, he says. A few small studies have pointed to the specific role of the hormones oestrogen and progesterone, but Triebner and his colleagues wanted to test these theories on a bigger scale.
His team interviewed 774 women aged between 40 and 67 years old, mostly white, living in seven European countries about their respiratory health and lifestyles. The team also carried out clinical exams and took blood samples. The women, some of whom hadn’t yet reached menopause, completed questionnaires about their sleep habits and health. The study didn’t include pre or post-menopausal trans men.
Nearly half the women reported that they had a “disturbing snore”, says Triebner. In addition, 14 per cent had irregular breathing and 13 per cent gasped while sleeping.
Blood analyses revealed that the participants’ oestrogen and progesterone levels varied widely, ranging from just a few units per litre in some women to tens of thousands of units per litre in others. Those variations had clear associations with sleep apnoea, he says. As the levels of oestrone – a kind of oestrogen – doubled, women were 19 per cent less likely to snore. And as progesterone levels doubled, women were 9 per cent less likely to snore.
Within the group of women who snored, there was a 20 per cent drop in the chances of having irregular breathing as oestrogen levels doubled. And a doubling in progesterone levels was linked to a 12 per cent lower likelihood of waking up feeling like they are choking.
All the findings were adjusted for the women’s stage of menopause, age, body mass index, smoking habits and educational backgrounds, some of which can affect hormone levels.
The results show a mechanism for the link between menopause and sleep apnoea. And they make sense given that certain kinds of oestrogen are involved in building respiratory muscles, and progesterone helps stimulate respiration, says Triebner.
Sleep apnoea is a potentially serious condition that has been linked to heart disease and stroke, and snoring can lead to relationship problems, says Triebner. “I believe an individualised hormone treatment after menopause has great potential to improve the quality of life of many women, and it most likely would severely improve sleep-disordered breathing,” he says.
Even so, further research is necessary. “What may be beneficial for one woman could be potentially harmful for another,” says Triebner
Journal reference: PLoS One, DOI: 10.1371/journal.pone.0269569
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