Stress, Cancer And HIV

October 2007 - A review of research into the relationship between stress and disease commissioned by the Institute of Medicine and published in the Journal of the American Medical Association has found that stress is a contributing factor particularly in triggering or worsening depression, cardiovascular disease and speeding progression of HIV/AIDS. Sheldon Cohen and Denise Janicki-Deverts both from Carnegie Mellon University, together with Gregory E. Miller of the University of British Columbia also considered underlying behavioral and biological mechanisms.

Sheldon Cohen, the Robert E. Doherty professor of psychology explained:

"The majority of people confronted with even traumatic events remain disease-free. Stress increases your risk of developing disease, but it doesn't mean that just because you are exposed to stressful events, you are going to get sick."

The authors found the strongest evidence came from research on depression, which found stress associated both with onset and relapse of the illness. Social stressors such as divorce and bereavement were particularly significant. They also found that depression is common among people who have been diagnosed with a serious illness and suggest that physical disease itself is stressful and can lead to depression. Chronic stress (such as that experienced at work) was found to contribute to cardiovascular illnesses such as coronary heart disease.

The authors concluded that studies on the relationship between stress and HIV/AIDS have produced less clear findings, but since 2000 have consistently demonstrated an association with progression of AIDS. They suggest this may be a result of complex and demanding drug treatments and could affect compliance. They also noted that autonomic nervous system changes caused by stress may influence virus replication.

The authors commented:

"Individuals differ with regard to rate of progression through the successive phases of HIV infection. Some remain asymptomatic for extended periods and respond well to medical treatment, whereas others progress rapidly to AIDS onset, and suffer numerous complications and opportunistic infections. Stress may account for some of this variability in HIV progression."

The authors suggest two possible pathways for the association between stress and disease: behavioral (such as lack of sleep, exercise, and treatment compliance, poor nutrition, increased smoking) and endocrinal (release of hormones that influence other biological processes, including the immune system).

The authors said:

"Effects of stress on regulation of immune and inflammatory processes have the potential to influence depression, infectious, autoimmune, and coronary artery disease, and at least some (e.g. viral) cancers."

They found inconsistent results in studies of the role of stress in cancer and highlight a number of difficulties in this field: delays in diagnosis; imprecision in measuring progression; an association may only be found in cancers influenced by sustained hormonal response and impaired immunity.

Sheldon Cohen concluded:

"We will need additional studies across a broader range of cancers before we can fairly evaluate the role of stress in cancer."

Cancer Beliefs

A survey of more than 6000 American adults published in Cancer Epidemiology, Biomarkers & Prevention found that a substantial number held fatalistic beliefs about cancer and were more likely to ignore preventive advice concerning exercise, quitting smoking and healthy nutrition. The study analyzed data from the National Cancer Institute's Health Information National Trends Survey, the first for almost 20 years to assess knowledge about and attitudes toward cancer prevention.

Jeff Niederdeppe, Ph.D., professor at the University of Wisconsin, Madison said:

"Many Americans seem to feel afraid and helpless in regards to cancer, which may be exacerbated by conflicting news reports and a general lack of education on the causes and prevention of cancer. They say 'well, there is nothing much you can do about it' and, as our survey shows, they indeed do nothing about it."

The survey asked participants for their response to three statements about cancer. About 47 per cent agreed that "It seems like almost everything causes cancer," while 27 per cent agreed that "There's not much people can do to lower their chances of getting cancer." Nearly three quarters (71.5 per cent) agreed that "There are so many recommendations about preventing cancer it's hard to know which ones to follow."

Respondents who held at least one of these beliefs were less likely to exercise weekly and eat five daily servings of fruits and vegetables. Those who believed that "it's hard to know which recommendations to follow" were more likely to smoke. The report explains that all three beliefs were associated with lower levels of education.

The report concludes that there has been little progress in changing the belief that "everything causes cancer" despite increased availability of information over the last 20 years. While not specifically investigating the impact of media coverage on fatalistic beliefs about cancer, the report suggests that constantly changing and sometimes conflicting messages may be contributing to public confusion and what is needed is simple, straightforward education about preventive measures.

Jeff Niederdeppe commented:

"Cancer is a difficult thing to talk about in the space of a single news story. Science values repetition, while the media values novelty. Those two concepts naturally butt heads, which can confuse people."

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