People who work in more demanding jobs may live longer after developing frontotemporal lobar degeneration (FTLD) than their counterparts who hold less skilled jobs, according to a new study.
This observation adds evidence to the "cognitive reserve" theory, lead author Lauren Massimo, PhD, from Pennsylvania State University in State College, told Medscape Medical News.
"Cognitive reserve suggests that educational and occupational experiences can provide some degree of resilience against the effects of neurodegenerative disease. Much of the evidence for this comes from Alzheimer's disease (AD)," she said. "Our study is the first to demonstrate protective effects of occupation in frontotemporal dementia, a common cause of young-onset dementia."
The study was published online April 22 in Neurology.
The researchers took a look back at 34 people with autopsy-confirmed FTLD and 49 with autopsy-confirmed AD. They classified and ranked each person's primary occupation based on US Census categories from 1 to 5: 1 = no occupation; 2 = unskilled laborers; 3 = operative and service workers; 4 = craftsmen and foremen, managers, administrators, clerical, and sales; and 5 = professional and technical workers.
For the entire cohort, median survival from onset of symptoms was 87.6 months. Patients with AD lived a median of 95.3 months and those with FTLD lived a median of 80.7 months.
In analyses adjusting for multiple potentially confounding factors, people with more challenging jobs (higher occupational level) were more apt to live longer than those with less challenging jobs, the researchers say.
People in the highest occupation level survived an average of 116 months, while people in the lower occupation group survived an average of 72 months, suggesting that individuals who had been in the professional workforce may live up to 3 years longer.
"Engaging in mental activities through occupation may be a way to boost the brain's reserve," Dr Massimo told Medscape Medical News.
Years of education were not associated with survival time in either group, nor was APOE ε4 status. However, the researchers caution that the AD sample comprised mostly young-onset AD (median age of 62.5 years) "and this may explain why APOE ε4 status did not have an effect on survival in our sample."
Overall, the researchers say their findings hint that higher occupational level provides a protective effect, lengthening survival time in autopsy-confirmed FTLD. "This is consistent with a biologically based model of reserve in which neuronal integrity and brain connectivity may be relatively robust to young-onset FTLD spectrum diseases and allow longer survival in the face of these neurodegenerative conditions."
The observed association between occupation and survival "stimulates questions about occupation-related effects on neuroprotection, and suggests the importance of incorporating this factor in treatment trials and prognostic considerations in persons with FTD," they conclude.
The study was supported by the US Public Health Service and the Wyncote Foundation. The authors have disclosed no relevant financial relationships.
Neurology. Published online April 22, 2015. Abstract
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Cite this: Complex Job May Extend Life After FTLD Diagnosis - Medscape - Apr 28, 2015.