May 19 2010 - Recent research from the University of Michigan Medical School published in the
American Journal of Gastroenterology found that nurses working shift patterns, especially those rotating
between day and night, had a significantly higher risk of developing Irritable Bowel Syndrome (IBS) and abdominal pain
compared to those permanently on day-time rotas.
Lead author Sandra Hoogerwerf, assistant professor of internal medicine said:
"We know that people participating in shift work often complain of gastrointestinal symptoms such as
abdominal pain, constipation and diarrhea. These are the same symptoms of IBS."
The researchers explain that IBS is the most common functional bowel disorder. It is not amenable to
diagnostic testing but is identified by clinical symptoms such as recurrent episodes of abdominal pain or cramping
associated with altered bowel habits.
The study recruited 399 nurses working three shift patterns: 214 on permanent day duty; 110 on
permanent nights and 75 rotating between the two. More than 85 per cent were women. Researchers identified a higher
prevalence of IBS and abdominal pain in participants working shifts, particularly those rotating between day and
night. This finding was independent of reported sleep disturbances.
Sandra Hoogerwerf explained:
"We know the colon has its own biological clock and that's what increases the likelihood of having a bowel movement in the first six hours of the day. Shift work can cause chronic disruption of that biological rhythm, resulting in that clock to constantly be thrown off and needing to adjust, creating symptoms of diarrhea, bloating, constipation and abdominal pain and discomfort."
The researchers suggest that patients with IBS should be alerted to the possible impact of their work
schedule on their condition.
Stress And Coronary Heart Disease
Research from Universite Laval's Faculty of Medicine published in the
Journal of the American Medical Association in 2007 has demonstrated that chronic job strain after a first heart
attack may double the risk of suffering a second one.
The researchers explain that previous studies had confirmed a relationship between work-related stress
and a first coronary heart disease (CHD) event, but the few studies conducted on the association with recurrent CHD
were limited in scope and inconsistent in their findings.
Researchers led by Chantal Brisson followed a group of 972 people aged 35 to 59 who had suffered a
heart attack. They were interviewed at six weeks, two and six years after returning to work concerning their health,
lifestyle, socio-demographic status, and degree of work stress. A job was defined as stressful "if it combined high
psychological demands (heavy workload, intense intellectual activity, and important time constraints) and little
control over decision-making (lack of autonomy, creativity, and opportunities to use or develop skills)."
The study found that 124 participants suffered a second heart attack and 82 experienced unstable
angina. People reporting high levels of work stress at six weeks and two years were twice as likely to suffer
another CHD event. Researchers found that the risk remained the same after allowing for variables such as severity of
the first heart attack, other health conditions, family history, lifestyle, socio-demographic status, personality,
and other work-environment factors. They also found that job strain did not increase the probability of experiencing
a second CHD event during the first two years.
Chantal Brisson commented:
"It makes sense on a biomedical level, since the pathological process at the source of the CHD
requires some time before it can manifest itself."
The researchers conclude that these findings should alert employers to the need to protect people from
potentially harmful situations when they return to work after a heart attack.
Chantal Brisson said:
"Employers and occupational health service professionals must find ways to modify the psychological demands of a job or the level of control over decision-making for people returning to work after a heart attack. It can be done, and encouraging autonomy, creativity, and the development of professional abilities in the workplace is not incompatible with a company's productivity."
A review of research into the relationship between stress and disease has
found that stress is a contributing factor particularly in triggering or worsening depression, cardiovascular disease
and speeding progression of HIV/AIDS.