Wet and cold weather linked to increased cancer rates


Wet and cold weather linked to increased cancer rates

For the first time, a study has discovered a link between living in cold, wet regions and increased risk of cancer.

It is common knowledge that increased exposure to UV rays from the sun increases the risk of skin cancer. However, a new study has highlighted precipitation and a cooler climate as a risk factor.

Previous research has shown a lot of disparity between cancer incidence and mortality rates in different U.S. regions – the highest rates seem to cluster towards the East Coast.

In this most recent study, the authors have explained that the differences have “been linked to racial, ethnic, behavioural, social, economic, and lifestyle factors”. They also stated that environmental and occupational factors may play a part.

Looking to the climate


The study, which has been published in the journal Environmental Engineering Science, examines the potential role of precipitation and climate zone in cancer risk. Climate zone is defined as “a variable that combines temperature and moisture level in a given area”.

Rather than suggesting that increased rainfall, temperature, and moisture directly cause cancer, they are instead suggesting that these factors “may increase the exposure to carcinogens by acting as carriers or increasing the natural biotic generation of carcinogens.”

This is the first study in the U.S. to look for a link between cancer rates, precipitation and climate zone.

The study was carried out by scientists who collected data on breast cancer, ovarian cancer, colorectal cancer, and prostate cancer. They also had access to county-led data of cancer incidence, climate, and demographics.


15 states were analysed at random – these states were Arizona, Arkansas, California, Connecticut, Georgia, Iowa, Massachusetts, New York, New Jersey, Oklahoma, South Carolina, Texas, Utah, Washington, and Wisconsin.

Significant relationships unearthed


The analysis was adjusted to control for age, gender, ethnicity, income level, population age, and diversity, due to those factors being able to influence cancer rates. Even after this adjustment, the researchers identified a strong association:

"[T]he effect of increased precipitation was an increase in incidence of all cancers. Likewise, climate zone was significant for all cancer outcomes."

Overall, the scientists discovered that cancer incidence rates were higher in very cold regions, compared with hot, dry climates. However, when the data was sorted into cancer types, there were some exceptions – for example, lung cancer was most prevalent in hot, dry zones.

The study also had some limitations – as the researchers only analysed 15 states, the pattern may not continue with the rest of the states, or other countries. The team also did not account for all cancer types within the analysis – like lung cancer, different types of cancer may not follow the patterns. Finally, as the study was of an observational nature, this could mean that there were other variables driving the relationship that the analysis did not consider or capture.

Further research is required to back up these findings as it was the first study of its type.


How might rain impact cancer?


The authors have provided some theories into how rain may impact cancer. They explained that on the East Coast, high rainfall leaches alkaline elements such as magnesium and potassium from the soil, making the soil more acidic. In acidic soil, as well as in colder areas, ammonia-oxidising bacteria are more common.

These bacteria convert ammonia into nitrites, and in more acidic conditions, nitrites may convert into nitrous acid. This is then released into the atmosphere. Health authorities consider nitrous acid a carcinogen.

However, if this was the case, it may be expected that airborne carcinogens would most affect lung cancer prevalence – but of course, it was found that the reverse was true.

Another possible theory involves vitamin D, which is produced by the skin in response to UV radiation from the sun. Researchers have suggested that vitamin D deficiency may also be a risk factor for some cancers, and so in rainier regions with less sunlight, this may be a factor.

A third theory from the authors outline an overworked metabolism. In colder climates, the body is put under metabolic stress as it attempts to maintain body temperature. The researchers theorise that this additional strain could increase the risk of cancer.

More research is required before the effect can be confirmed. If further studies do confirm the effect, the reasons are likely to be very complex and multifaceted, potentially involving all or none of the theories above.




Dr Herbert Benson - The Summary of an Incredible Life

Dr Herbert Benson - The Summary of an Incredible Life

Herbert Benson was born on April 24th 1935 in New York and
was the son of Charles and Hannah Benson. ...

College of Integrative Medicine Recruiting for CMA Members only

Understanding the Science of Acupuncture

The COMPLEMENTARY MEDICAL ASSOCIATION (The CMA) © 2012. No part of this site may be reproduced without the express permission of The Complementary Medical Association. If used without prior consent a charge of US $1,000 per article, or mini section is paid (US $50 per word (minimum) will be charged. This is not meant to reflect a commercial rate for the content, but as a punitive cost and to reimburse The CMA for legal fees and time costs). Use of the contents, without permission will be taken as consent to bill the illegal user in full.