April 21, 2010
By Richard Alleyne
Scientists believe a combination of cold temperatures and lack of sun could help explain higher rates of the disease in northerly parts of the world.
Poor exposure to the sun’s rays can lead to vitamin D deficiency, which may increase prostate cancer risk, it is claimed.
At the same time, cold weather might help to slow the degradation of cancer-triggering industrial pollutants and pesticides, said US researchers.
Cold temperatures were also believed to help the chemicals precipitate out of the atmosphere and fall to the ground.
Dr Sophie St-Hilaire, who led the scientists from Idaho State University, said: “We found that colder weather, and low rainfall, were strongly correlated with prostate cancer.
“Although we can’t say exactly why this correlation exists, the trends are consistent with what we would expect given the effects of climate on the deposition, absorption, and degradation of persistent organic pollutants including pesticides”.
Around one in six men will develop prostate cancer in their lifetime.
Across the northern hemisphere, reported incidence of the disease is greater in higher latitudes, according to the scientists.
The rate varies by about five per cent.
Each year in the UK, around 35,000 men are diagnosed with prostate cancer and 10,000 die from the disease.
It is known that some pollutants can cause cancer, said the researchers writing online in the International Journal of Health Geographics.
Experts believed that cold weather slowed the chemicals’ degradation and caused them to precipitate to the ground.
Rain and humidity were also thought to play important roles in their absorption and degradation.
Dr St-Hilaire said: “This study provides an additional hypothesis for the north-south distribution of prostate cancer, which builds on the existing supposition that individuals at northern latitudes may be deficient in Vitamin D due to low exposure to UV (ultraviolet) radiation during the winter months.
“Our study suggests that in addition to vitamin D deficiency associated with exposure to UV radiation, other meteorological conditions may also significantly affect the incidence of prostate cancer”.
The scientists analysed prostate cancer data for every US county between 2000 and 2004.
They found that lower temperatures correlated with higher rates of prostate cancer, after adjusting for UV radiation, local pesticide use, rainfall, snowfall and other factors.
“We hypothesise that temperature may be associated with the incidence of prostate cancer by modulating exposure to POPs (persistent organic pollutants), some of which have been linked to the disease,” the researchers wrote.
Organic chemicals tended to exist in a solid rather than a gaseous form at cold temperatures, they pointed out. This would cause them to fall to earth.
Temperature also affected the degradation of POPs in the soil and atmosphere.
November 16, 2009
By Laura MacInnis
Flu infections may be peaking in some parts of the northern hemisphere, but are still spreading fast in others, the World Health Organization said on Friday.
In an update on the H1N1 swine flu virus, the WHO said parts of the southern and southeastern United States, as well as Iceland and Ireland, seemed to have weakening levels of disease after an unusually early start of the winter flu season.
But the U.N. agency, which declared a global flu pandemic in June, said that big sections of the United States were still experiencing “widespread and intense” flu infections.
It described waves of outbreaks across Canada and in Mexico, where the first severe cases were identified earlier this year.
“In Europe and central Asia, overall influenza transmission continues to intensify,” the WHO said, adding that almost all the influenza viruses analyzed in Europe in recent weeks have been the H1N1 strain and not seasonal flu.
The pandemic virus has now spread to 206 countries, with the latest reported laboratory-confirmed cases in Somalia, Nigeria and Burundi. There have been more than 6,250 deaths to date, mostly in the Americas region, according to the WHO toll.
While saying “high to very high intensity of respiratory diseases” have been reported in some parts of Europe including Belarus, Bulgaria and Russia, it said experts were now less concerned about a big outbreak in Ukraine.
“The initial analysis of information from Ukraine indicates that the numbers of severe cases do not appear to be excessive when compared to the experience of other countries and do not represent any change in the transmission or virulence of the virus,” it said in a statement posted on the WHO website.
Ukraine and Belarus have recently extended school breaks due to fears about the pandemic virus while Afghanistan declared a health emergency and ordered its schools shut for three weeks to battle it.
WHO spokesman Gregory Hartl said that school closures were among steps that could slow viral spread at the beginning of an outbreak, but had less usefulness once the flu had reached 5 percent of a given population.
“After the virus becomes more widespread in a country, closing schools has less of an impact,” he told a news briefing earlier this week. “If you take a decision to close schools and universities and other institutions you have to be aware there are social and economic consequences of this decision.”
In new guidance also published on Friday, WHO experts said that people planning “mass gatherings” of 1,000 people or more should consult with public health authorities to make sure the events do not amplify the spread of pandemic flu.
“The decision to proceed with a mass gathering or to restrict, modify, postpone or cancel the event should be based on a thorough risk assessment,” it said in the recommendations published on www.who.int.
Guests and participants should also be encouraged to follow the same flu-fighting steps the WHO has widely urged, including to stay home and especially avoid travel when unwell, to clean hands frequently and to cover coughs and sneezes.
“Where possible, organizers should consider distancing measures to reduce close contact among people during a mass gathering,” it said, suggesting for example that transport be staggered and food and drink stations spread out to avoid unnecessary congregation.