Job seekers prepare for a career fair.
As if being unemployed isn't bad enough, the stress of long-term joblessness may cause men to genetically age faster, a new large study suggests.
Finnish and British researchers found that young men who had been unemployed for 500 days or more experienced a significant shortening of their telomeres, sections of chromosomes that may predict health and lifespan.
While the science of the telomere-health link is still developing, a number of studies over the past decade have associated shorter telomeres with cardiovascular disease, infections, psychological distress such as depression, and higher overall mortality.
Telomeres sit at the ends of chromosomes. They’ve often been compared to the plastic caps at the ends of shoelaces that protect the laces from unraveling. But telomeres degrade — and when they do — the cell either malfunctions or dies.
That’s part of aging. However, the process can be accelerated. The exact biological triggers for this premature shortening “is complicated,” suggested Katherine Theall, an associate professor in Tulane University’s Department of Global Community Health and Behavioral Sciences.
“There are probably many different mechanisms,” she told NBC News, “but the stress response has been shown to be associated with shorter telomeres.”
For example, while studying telomere length in children, Theall found that those living in highly disordered neighborhoods in New Orleans had, as a group, shorter telomeres than children living in more stable neighborhoods.
Many such studies have been small and used mixed populations, but the research released Wednesday in the journal PLoSOne, used a very large and homogenous group of people — 2,713 men and 2,907 women — from the Northern Finland Birth Cohort 1966, a group that’s been tracked for decades.
All the people had blood samples taken when they were 31. The researchers used these stored samples to extract a type of blood cell called leukocytes, often used for telomere studies. They then matched samples to employment records, health indicators, and circumstances known to affect telomere length, like smoking, drinking, and the age of their fathers when they were born.
After controlling for such variables, they found that men who had experienced unemployment of at least 500 days had a 2.4-fold greater risk of being in the 10 percent of people with the shortest telomeres.
There was no such effect for women, though the authors point out that the women in the study were rarely unemployed for 500 days, and many spent time on family leave during prime childbearing years.
“The stress resulting from long-term unemployment appeared to be of key importance,” they wrote. “Unemployment has been linked with numerous poor health outcomes including mortality, and now also with shorter telomere length, a potential biomarker of premature aging.”
So this study could be a warning about the future health of whole populations affected by economic and social stress.
For example, in Spain, about half of workers aged 18 to 25 are unemployed. Italy is suffering from 12 percent unemployment, France over 10 percent, the U.S., 7.3 percent.
Still, as Theall said, it’s complicated. A study conducted by researchers from the Centers for Disease Control and Prevention and published in August in the journal Occupational and Environmental Medicine, found “no mean differences in telomere lengths across current employment status, occupational category, [or] job strain categories….” The ages in that much smaller study group were 45 to 84.
Such apparent contradictions are why Theall called this new work “important.”
“What are the critical periods for stress exposure to have the biggest impact? That’s interesting. There’s not a lot out there that looks at long-term effects of stress by age and sex.”
Brian Alexander is a frequent contributor to NBC News and a co-author of “The Chemistry Between Us: Love, Sex, and the Science of Attraction.”
First published November 20 2013, 3:30 PM