Bili Buzz - Popular Science, Nature, Medicine, Archeology, Future & Myths

Of all the controversies surrounding cancer, the role of Vitamin D is one of the most contentious. It has been known for years that this essential nutrient is produced in the body when it is exposed to sunlight. It can also come from our diets, but most people do not eat enough fish to make the amount we need for healthy bones.

The public health messages about avoiding too much sunlight have been criticised in the past few years by those who believe we have to expose ourselves a bit in order to make Vitamin D. Some doctors believe the medical community has been unwilling to accept evidence that the vitamin can play a significant role in protecting against bowel cancer and other diseases, and that the ’safe sun’ messages have been overplayed. According to Professor Lesley Rhodes, whose work in Manchester is funded by Cancer Research UK, people may not need too much sunlight to make the nutrient. ‘Sunlight is important, but after a while our ability to make Vitamin D is switched off. We think that it may be just ten to 15 minutes you need to get the full benefits of the sun, before you start to burn.’

A daily dose of aspirin reduces a woman’s chance of developing a particular type of breast cancer by 16%, according to a study of more than 126,000 women.

The latest research backs up a review of 21 studies which found that anti-inflammatory drugs such as aspirin reduce breast cancer risk by up to 20%. About 45,000 women a year in the UK are diagnosed with breast cancer.

In the new study, Dr Gretchen Gierach and colleagues at the US National Institutes of Health in Rockville, Maryland, studied 126,124 women aged between 51 and 72. When the study started, none of the volunteers had breast cancer. During follow-ups between 1995 and 2003, 4,501 of the women developed breast cancer. The team found that women who took aspirin daily were 16% less likely to develop so-called oestrogen receptor positive breast cancer. Around three-quarters of breast cancers are oestrogen receptor positive.

Contrary to previous research, the study did not find a reduction in breast cancer risk overall in the group of women who used aspirin regularly, and did not find that other nonsteroidal anti-inflammatory drugs (NSAIDs) reduced breast cancer risk.

Aspirin is thought to influence cancers by blocking the action of an enzyme called cyclooxygenase. This in turn lowers the amount of oestrogen in the body. The results are reported in the journal Breast Cancer Research.

Liz Baker, science information officer at Cancer Research UK, said anyone considering taking aspirin regularly should consult their doctor first. “Weighing up the risks and benefits, it’s too soon to recommend aspirin as a way of reducing the risk of cancer.”

In a separate study, researchers have found that having a child appears to give mothers some protection against breast cancer.

Dr VK Gadi, at the University of Washington in Seattle, and colleagues found that stem cells left behind in the mother by the foetus appear to make her less likely to develop breast cancer.

The study is reported in New Scientist magazine.

Breathing in air pollution from traffic fumes can raise the risk of potentially deadly blood clots, a US study says.

Exposure to small particulates - tiny chemicals caused by burning fossil fuels - is known to increase the chances of heart disease and stroke.

But the Harvard School of Public Health found it also affected development of deep vein thrombosis - blood clots in the legs - in a study of 2,000 people.

Researchers said the pollution made the blood more sticky and likely to clot.

The team looked at people living in Italy - nearly 900 of whom developed DVT.

Blood clots which form in the legs can travel to the lungs, where they can become lodged, triggering a potentially fatal pulmonary embolism.

The risk of DVT is known to be increased by long periods of immobility. In particular, passengers on long-haul flights have been shown to be vulnerable, but so are people who spend long periods of time sitting at their office desk without exercising, or walking around.

Researchers obtained pollution readings from the areas they lived and found those exposed to higher levels of small particulates in the year before diagnosis were more likely to develop blood clots.

The Archives of Internal Medicine report said for every 10 microgrammes per square metre increase in small particulates, the risk of developing a DVT went up by 70%.

Air quality guidelines generally state that small particulate concentrations should not exceed 50 microgrammes.

Risk Factor

Lead researcher Dr Andrea Baccarelli said: “Given the magnitude of the effects, our findings introduce a novel and common risk factor into the development of DVT.

“And, at the same time, they give further substance to the call for tighter standards and continued efforts aimed at reducing the impact of urban air pollutants on human health.”

Dr Beverley Hunt, medical director of the DVT charity Lifeblood, said: “We have known for some time that air pollution has been associated with increased risk of heart attack and stroke.

“This study shows for the very first time that air pollution also increases the risk of clots in the veins and tells us why.

“It’s an exciting finding because air quality is something we can improve on through tightening air quality legislation.”