Women who have been severely injured are 14 percent more likely to survive than similarly injured men, a new Johns Hopkins study has suggested.
According to the researchers, the difference may be due to the negative impact of male sex hormones on a traumatized immune system.
Both men and women have androgens (male sex hormones, including testosterone) and estrogens, but in different ratios that change over time. The new findings could lead to ways to improve survival in badly injured men, such as giving androgen-blocking drugs to male patients who have been critically injured.
"Female sex hormones appear to give women better resiliency to extreme injury, while male sex hormones seem to worsen their survival after severe trauma", said Adil H. Haider, an assistant professor of surgery at the Johns Hopkins University School of Medicine and the study's leader.
"And if we can come up with ways to manipulate those hormones in men, for example by temporarily blocking sex hormones, we may be able to improve their survival."
Haider and his colleagues analyzed information from the National Trauma Data Bank on more than 48,000 patients who, between 2001 and 2005, were severely injured and arrived at an emergency room with low blood pressure, a sign of significant blood loss. They split the data into three categories - children 12 years and younger, teens and adults ages 13 to 64 and seniors age 65 and older.
In the younger patients, those whose sex hormones hadn't developed yet, and in the older patients, whose hormone activity was expected to be significantly diminished, survival did not vary based on gender. It was only the middle group of 13-to-64-year-olds - those most likely to have had the highest levels of estrogen and progestin or testosterone - where women were significantly more likely to survive. The survival advantage was there even when factors such as race, insurance status and source of injury were taken into account.
"The results of the study suggest that female sex hormones provide an advantage and help women survive after trauma."
"As expected, the female-to-male advantage is restricted to the group likely to have more sex hormones, rather than in the very young or the old," he added.
The study has been published in the September issue of The Journal of Trauma.