WOMEN are twice as likely as men to die of an asthma attack, a top charity warns.
Asthma + Lung UK said two thirds of asthma deaths in the past five years have been women – 5,100 compared to 3,200 men.
Female sex hormones including oestrogen may be to blame for triggering worse breathing attacks.
Sarah Woolnough, chief executive of the charity, said: “Gaps in our knowledge are failing women.
“Many are struggling with debilitating asthma symptoms, stuck in a cycle of being in and out of hospital and, in some cases, losing their lives.”
There are around three million women in the UK with asthma and 2.4million men.
Attacks cause the airways to tighten up and make it difficult to breathe.
While boys are more likely to have the condition as children, many grow out of it and women are more likely to develop it in puberty or adulthood.
Asthma + Lung UK said female hormones oestrogen and progesterone can make symptoms worse as they push down levels of male testosterone, which strengthens the airways.
Adult women are 2.5 times more likely to be admitted to hospital with asthma than men and more likely to struggle to control the condition, the charity added.
Experts are calling for more research to better understand why women are badly affected and try to boost survival.
Ms Woolnough added: “By understanding the role of sex hormones in asthma, we could transform the lives of millions of women across the world.
“We urgently need to see more investment in research in this area to save lives.”