Working in a stressful job for 15 years increases the risk of getting cancer, according to new research
This prolonged exposure raises the risk of lung, colon, rectal and stomach cancer – along with non-Hodgkin lymphoma that develops in the vessels and glands, according to the first study of its kind.
Researchers say the results raise the question of whether chronic psychological stress should be viewed as a public health issue.
The unique study assessed the link between cancer and work-related stress as perceived by men throughout their working life.
And this was not limited to high work load and time pressure, reports Preventive Medicine.
Customer service, sales commissions, responsibilities, having an anxious temperament, job insecurity and financial problems were all sources of stress listed by the participants.
Others included challenging or dangerous work conditions, employee supervision, interpersonal conflict and a difficult commute.
Dr Audrey Blanc-Lapierre, of Quebec University, said: “One of the biggest flaws in previous cancer studies is none of them assessed work-related stress over a full working lifetime – making it impossible to determine how the duration of exposure to work-related stress affects cancer development.
“Our study shows the importance of measuring stress at different points in an individual’s working life.”
In the study 3,103 patients in Montreal who had been diagnosed with one of eleven types of cancer between 1979 and 1985 were interviewed along with 512 other individuals who acted as controls.
Subjects described in detail each job held during their lifetime – including the occurrence of stress – and its reason.
On average participants had held four jobs – with some holding up to a dozen or more during their working lifetime.
Significant links to five of the eleven cancers considered by the researchers were revealed.
These were observed in men who had been exposed to 15 to 30 years of work-related stress – and in some cases more than three decades.
The links was not found in those who had held stressful jobs for less than 15 years.
The most stressful jobs included firefighter, industrial engineer, aerospace engineer, mechanic foreman and vehicle and railway-equipment repair worker.
Dr Blanc-Lapierre said: “The association between perceived workplace psychological stress – over the entire work career – and cancer among men has never been assessed.
“Subjects reported changes in stress level over their career. Perceived stress was ascribed to several sources including high demand and time pressure, financial issues, job insecurity and hazardous conditions.
“Prolonged exposure to perceived stress at work was associated with greater odds of cancer at five out of eleven sites.
“While over reporting of stress by cases cannot be fully ruled out, these associations, if substantiated, would bear important public health significance.
“Prospective studies building on detailed stress assessment protocols considering all sources and changes over the career are necessary.”
But the researchers said the results are as yet unsubstantiated because they are based on a summary assessment of work-related stress for a given job.
There is now a need for epidemiological studies based on reliable stress measurements – repeated over time and that take all sources of stress into account.
Although stress can cause a number of physical health problems previous research suggesting it can cause cancer is weak.
Some studies have indicated a link between various psychological factors and an increased risk of developing cancer, but others have not.
Apparent links between psychological stress and cancer could arise in several ways. For example, people under stress may start smoking, overeating, or drinking alcohol, which increase a person’s risk for cancer.
Or someone who has a relative with cancer may have a higher risk for cancer because of a shared inherited risk factor – not because of the stress induced by the family member’s diagnosis.
A few studies have found a link between stress and breast cancer but they have often only looked at a small number of participants or asked women to recall if they were stressed before they developed the disease – which can be unreliable.