Artificial light and prostate cancer (another media monster)

Here is another of those “scientific” studies that is already being spread rapidly across the Internet and other media but which is of highly dubious scientific merit. According to a report issued by HealthDay, “Men who live in countries with the highest levels of artificial light at night appear more likely to develop prostate cancer.”

In what seems to be a complete copy of the University of Haifa’s original media release, it states that the researchers “looked at the incidence of prostate cancer among men in 164 countries and also studied data on nighttime lighting.”

We don’t know where the researchers were getting accurate data on the incidence of prostate cancer, because that only exists for a tiny percentage of the world’s nations. It can’t have been from the source they claim to have used. If you actually look at that source, for most countries, it is clear that the currently available data are inaccurate, outdated, and based only on relatively late stage hospital diagnoses and mortality (as opposed to actual community incidence data that exist in the United States and a relatively small number of other nations).

It is also remarkably unclear what is meant by “data on nighttime lighting.” Are we referring to internal household electric lighting? If so, this is relatively widespread today, even in many poor rural communities in parts of Africa and Asia. However, again according to the original media release, “Data on the levels of lighting at night were gathered from DMSP (Defense Meteorological Satellite Program) satellite images.” And those are supposed to be able to tell me that the lights are on inside the house where you are sitting (for example, on a rural farm in the veld in South Africa)? Vast amounts of that lighting is street and building lighting that is of some value but which isn’t actually having high impact on individuals.

According to the research team, they were able to demonstrate that, “The incidence of prostate cancer in countries with low nighttime lighting exposure was 66.77 per 100,000, compared with 87.11 per 100,000 among men with medium exposure (30 percent greater risk), and 157 per 100,000 among men with high exposure (80 percent greater risk).”

They go on to suggest that “a number of theories could explain the apparent link between nighttime lighting and increased prostate cancer risk, including: suppression of melatonin production; suppression of the immune system; and disruption of the body clock due to confusion between night and day.”

The “New” Prostate Cancer InfoLink would (respectfully) suggest that there is a much simpler explanation of this correlative (as opposed to causative) data: men in less technologically advanced societies may have (a) lower life expectancies; (b) a far lower likelihood of early prostate cancer diagnosis; and (c) a low probability that their diagnosis will be reported to any sort of national database even if they are diagnosed, than men in technologically more advanced societies (who will also be more likely to benefit from high quality artificial lighting at night).

We sincerely hope that your tax dollars weren’t paying for this study — but we have a nasty suspicion that they probably were. In  a particularly bizarre note in the media release about this study, the researchers are quoted as stating,”This does not mean that we have to go back to the Middle Ages and turn the lights out on the country. What it means is that this link should be taken into account in planning the country’s energy policies.” What?

2 Responses

  1. I communicated via email with one of the women who took part in a symposium at NCI about these studies in breast cancer. It was about melatonin. She said that white light at night stops melatonin production. Your body produces melatonin, which effects the body’s natural immune system dramatically, only at night when you are in a completely dark environment.

    If melatonin is a factor in the increase of cancers shouldn’t we try to find that out? Clinical trials to prove this are very difficult because blood samples have to be taken from volunteers many times during the night. Not many people will volunteer to do that.

    How do you suggest that we attempt to validate what the scientists believe may be happening? If what they say is accurate then that could make a big difference in cancer incidence. How do we deal with it, if true, then that means major changes.

    It may sound crazy BUT it may be true and further study may be appropriate. This sounds like a study to attempt to get more information that will help us to get support for further study.

  2. The possibility of a link between cancer risk, melatonin production, and various types of light exposure has been known for at least 20 years (and probably longer). If people want to actually prove that there is a real connection in specific types of cancer, they need to do well designed studies to demonstrate this, not publish garbage (in the hope that it will generate funding or for any other reason). Are those well-designed studies going to be difficult? Yes they are? Are they even worth doing? I’m not so sure. What would we really do if they were proved to be true and showed a (say) 5 percent increase in risk for prostate cancer or breast cancer?

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