FTD is a family of devastating disorders of the brain that lead to the progressive loss of brain cells (neurons) in the frontal and temporal regions of the brain, most commonly in patients between ages 50 and 65 and often causing symptoms ranging from behavioral impairments to language difficulty. Nearly 10,000 patients are diagnosed with the disease each year. As the disease progresses, it can slowly deprive an individual of their cognitive abilities, personality and eventually their independence.
“There is a notion that ones ‘cognitive reserve’ is built up over the course of a lifetime through experiences such as education, occupation and mental engagement,” said Lauren Massimo, PhD, CRNP, a post-doctoral fellow in the department of Neurology in Penn’s Frontotemporal Degeneration Center. “We believe that those with higher occupational levels are able to build up an additional level of defense against the disease through rich neural connectivity and this could contribute to longer survival.”
Massimo and colleagues retrospectively examined the autopsy reports of 83 patients in the Center for Neurodegenerative Disease Research at the University of Pennsylvania, 34 of whom had confirmed FTD and 49 with autopsy-confirmed Alzheimer’s disease (AD).
Each patient’s occupation was recorded and ranked according to U.S. Census categories, with jobs such as factory workers and service workers in the lowest level; jobs such as tradesworkers and sales people in the next level; and professional and technical workers, such as lawyers and engineers, in the highest level. Education level was also measured in years of schooling completed.
Their analysis showed that median survival for patients with FTD was six years and nine months, and just shy of eight years for those with AD, with survival defined as the time from symptom onset until death.
Further analysis showed that patients with FTD in the highest occupation level survived an average of nine years, while people in the lower occupation group survived an average of six years, suggesting that higher occupation level is associated with longer survival in patients with FTD. Occupational level was not associated with longer survival time for patients with Alzheimer’s disease. Interestingly, the team found that years of education were not associated with survival time for either group.
“These results provide support for the protective effects of occupation in FTD,” Massimo said. “There may be other factors at work here such socioeconomic factors tied to occupational status that contributes to the longevity of this group. Further studies might also want to expand the sample size and occupations characterized, as ours left no room for occupations such as 'homemaker' or those outside traditional lines of work.”
Other Penn researchers include Jarcy Zee, PhD; Sharon X. Xie, PhD; Corey T. McMillan, PhD; Katya Rascovsky, PhD; David I. Irwin, MD; Murray Grossman, MD, MedD.
This research was funded by the U.S. Public Health Service (F32NR014777, AG017586, AG015116, AG010124, AG043503, NS053488 and NS044266) and the Wyncote Foundation.