Women aged 65 and older who fracture a hip are more than two times as likely to die in the year following injury than are women with intact hipbones, according to a new study published online in the Archives of Internal Medicine.
The study included 5,500 mostly white women, who were tracked from 1986 to 2005 as part of a larger cohort study funded by the National Institutes of Health. Of this group, 1,116 women suffered hip fractures. Researchers matched each of these women with four other women of the same age who didn’t break a hip, as a control group, and found that their risk of death increased significantly in the 12 months following fracture.
Although previous studies have associated hip fracture and mortality, it has not been clear whether that link was due to underlying illness. The current study is the first to try to establish a causal relationship between breaking a hip and death. In addition to assembling an age-matched control group, the researchers adjusted for bone mineral density (BMD), and chronic conditions such as diabetes, hypertension and stroke.
The study found that 17% of the 1,116 women who suffered a hip fracture died within a year, compared with 8% of the control group. The risk was even higher for women aged 65 to 69 who broke a hip: they were five times as likely to die within 12 months as the healthy control group.
Women aged 70 to 79 were about twice as likely to die following fracture, and those aged 80 or older had no difference in risk of death, compared with their age-matched control groups, the study found.
“You’d think a 65-to-69 year-old would be more able to bounce back from a hip fracture,” Erin LeBlanc, a study author and investigator at the Kaiser Permanente Center for Health Research, which led the study, told the Wall Street Journal‘s Health Blog. But because this younger group has a lower risk of death from other causes, compared with older women, a hip fracture may be more likely to translate into a higher mortality risk, the WSJ reports.
Further, when researchers took a closer look at the over-80 group, they found that although hip fracture did not increase the risk of women’s death on average, it did make a difference in women who reported good or excellent health. In this healthy subgroup, hip fracture nearly tripled the risk of death within a year, another indication that there’s something about breaking a hip in particular — whether it’s the surgery, hospitalization or immobility — and not an underlying health problem that may hasten death.
In addition, the researchers found, more than half of the deaths in the fracture group occurred within three months of the injury. Nearly three-quarters occurred within six months.
Women who died following a hip fracture were about as likely to die of heart disease, stroke and sepsis — the top three causes of death — as the control group. Other causes of death included dementia, Alzheimer’s and cancer.
LeBlanc suggests that aging women take preventive measures to protect their bones, such as taking vitamin D and calcium to maintain bone density, exercising to enhance strength and balance, and avoiding smoking or overindulging in alcohol. Women should also be screened for osteoporosis.
“Thinning of the bones is silent,” LeBlanc told Health.com. “It doesn’t hurt, and if you’re not proactive you might not know you have it until you break something.”
Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.