Women going through menopause should pay special attention to their weight to avoid respiratory problems.
"After menopause, allergic and asthmatic complaints are almost double the level reported by women who are still menstruating," said Dieter Koehler of Germany's association for pneumology and respiratory medicine.
The onset of respiratory problems is linked to falling oestrogen after monthly bleeding suspends, the association said, citing research conducted by Norwegian scientists. According to the research, oestrogen, the female sex hormone, apparently has a protective effect on the lungs.
Women who are especially thin or underweight are particularly affected by the problem, the association said. In those women the oestrogen level after menopause sinks to an especially low level because their bodies store so little fat. However, the study showed that overweight, menopausal women also show poor lung function.
The association recommends women who have entered menopause make every effort to reach and maintain a normal body weight. The ideal body mass index for menopausal women is 25.
More than 1,300 women aged 45 to 55 from nine European countries and the US participated in the Norwegian study.