Discoveries

Research Briefs

Backdrop
Back surgeries are getting increasingly complex, according to a team of researchers that included Dartmouth-Hitchcock orthopaedist Sohail Mirza, M.D. The overall rate of surgery for lumbar spinal stenosis—a narrowing of the spinal canal in the lower back—dropped between 2002 and 2007 among Medicare beneficiaries, but the rate of the most complex surgeries for this condition grew rapidly. As a result, Mirza and his coauthors noted, "although the overall procedure rate fell 1.4%, aggregate hospital charges increased 40%."

Knife point
After nine years of waiting, surgeons and cardiologists at Dartmouth-Hitchcock and around the country finally got the results of a much-anticipated clinical trial. DHMC was one of 117 institutions that took part in the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST), which assessed whether endarterectomy (a surgical procedure) or stenting (a minimally invasive procedure) is more effective at preventing strokes and heart attacks in at-risk patients. The trial showed that, overall, the procedures are equally effective. But patients older than 70 did somewhat better with surgery, while those 69 and under did better with stenting.

DMS's Kent Hymel, M.D., led a study of head trauma in children under 3 years of age. The deeper the injury, his team found, the more likely it was to have been the result of abuse.

Healthy communication
Dartmouth researchers reported that communication between mothers and daughters plays a large role in determining whether young women receive the HPV vaccination. They surveyed almost 1,000 female undergraduates to determine their knowledge of HPV, their perceptions of HPV risk, and the openness of their communication with their mothers. Just under half (49%) had received at least one shot in the three-shot vaccine series. "The mother's approval of HPV vaccination, mother-daughter communication about sex, and daughter's perceptions of vulnerability to HPV were positively associated with vaccination status," the researchers wrote in Pediatrics.

Water proof
Tens of millions of people use drinking water containing levels of arsenic—a known carcinogen—above the maximum recommended by the World Health Organization. Now, DMS researchers have reported that arsenic might trigger a cell signaling pathway called Hedgehog that is associated with several cancers. Patients exposed to arsenic had high levels of Hedgehog signaling. "Our study provides for the first time evidence that links activation of the Hedgehog pathway with arsenic exposure," they wrote in the journal Cancer Research.

More Medicare enrollees are getting new joints, reports the Dartmouth Atlas of Health Care; from 2000-01 to 2005-06, hip replacements rose 15%, knees 48%, and shoulders 67%.

Sensational study
A DMS-led team assessed if teenagers who exhibit sensation seeking—the "tendency to seek out novel and exciting stimuli"—are more likely to start drinking or smoking. They surveyed adolescents aged 10 to 14 and used a series of questions to rate their sensation- seeking tendencies. The team reported in Addiction that "sensation seeking was found to be a moderately strong predictor of binge drinking and a strong predictor of established smoking." The authors argue that interventions to prevent binge drinking and smoking among adolescents should primarily target sensation seekers.

A PSA about PSA screening
"There is growing concern that older adults are at risk for exposure to potentially harmful treatments for which the promised benefit is small, if not absent," wrote Julie Bynum, M.D., and her coauthors in the Journal of the American Geriatrics Society. They examined rates of prostate-specific antigen (PSA) screening in men 80 and older. PSA testing can signal a risk of prostate cancer but also involves potential harms and, in some populations, a low likelihood of benefit. Bynum found that rates of screening in this age group varied from 2% to 38% and that regions with higher rates had higher overall Medicare expenditures.

DMS's Laura Barre, M.D., studied 183 older adults and found they were at higher risk of frailty (such as weight loss, weakness, or low activity) if they had a serious mental illness.