Sunday, December 18, 2011

Children whose father smoked at time of conception have 15% greater risk of developing leukaemia

This is almost certainly a social class effect. Smoking is correlated with all indices of social disadvantage and the poor are less healthy anyhow so it is most likely poverty rather tham smoking that creates the association with leukaemia

Children whose fathers smoke around the time of their conception have a 15 per cent higher risk of developing the most common form of childhood cancer, a type of leukemia, say researchers. The study credits a number of factors in children developing acute lymphoblastic leukemia (ALL) and follows others that have also found an increased risk.

'Study results suggest that heavier paternal smoking around the time of conception is a risk factor for childhood ALL,' wrote researchers led by Elizabeth Milne at the Telethon Institute for Child Health Research in Australia. The findings were published in the American Journal of Epidemiology.

Although ALL is the most common childhood cancer, it is still rare, affecting about three to five children out of every 100,000. The researchers surveyed the families of nearly 300 children with ALL, asking about the smoking habits of both parents. They also compared these families to those of more than 800 children of similar ages who did not have leukemia.

The mothers' smoking behaviour had no impact on the children's risk of developing the cancer, but children whose fathers smoked at all around the time of their conception were 15 per cent more likely to develop leukemia. Those whose fathers smoked at least 20 cigarettes per day around that same time were 44 per cent more likely to be diagnosed with the disease.

Of nine earlier reports the researchers used in their comparison with the current study, six also found an increased risk.

'The importance of tobacco exposure and children's cancers has been overlooked until recently,' said Patricia Buffler, a professor at the University of California, Berkeley, who was not involved in the study. She added that since tobacco is full of toxins, including carcinogens, it was possible that there could be damage in the cells that produce sperm.

Milne agreed, noting: 'Sperm containing DNA (damage) can still reach and fertilize an ovum, which may lead to disease in the offspring.'

But she added that the study did not prove that DNA damage in the sperm caused ALL in the children, since the disease was likely to be caused by a number of factors. Other environmental factors tied to a greater chance of developing childhood leukemia are ionizing radiation such as x-rays, and the mother's exposure to paint or pesticides while pregnant.


Iron supplements 'could help stave off DVT and other life-threatening blood clots'

This concerns people with one particular disease only. It may have no application to others

Iron supplements could be used to prevent deep vein thrombosis and other life-threatening blood clots, new research shows.

Each year, one in 1,000 people in Britain is affected by clots that form in the veins, and scientists now believe the risk could rise in those with a lack of iron. DVT is often associated with long distance air travel and other situations that involve being immobile for long periods of time.

Clots frequently form in the legs causing painful swelling and, in some cases, a danger that lumps of blood will dislodge and travel to the lungs with fatal results.

Researchers at Imperial College London studied 609 patients with blood vessel disease haemorrhagic telangiectasia, who have a higher risk of blood clots. They found that this increased risk disappeared when the HHT sufferers took iron supplements. Many of the patients had low iron levels, because of iron loss through excessive bleeding - a symptom of HHT.

The study, published in the journal Thorax, found that a blood-iron level of six micromoles per litre compared with the normal mid-range figure of 17 micromoles led to a 2.5-fold increase in venous thrombosis risk.

Lead researcher Dr Claire Shovlin, from the university's National Heart and Lung Institute, said: 'Our study shows that in people with HHT, low levels of iron in the blood is a potentially treatable risk factor for blood clots. 'There are small studies in the general population which would support these findings, but more studies are needed to confirm this. 'If the finding does apply to the general population, it would have important implications in almost every area of medicine.'

Iron deficiency anaemia is thought to affect at least one billion people worldwide. Its association with clotting may have been missed before because blood iron levels fluctuate during the day. Other markers of iron deficiency can go unnoticed if certain medical conditions are present.

The scientists said that obtaining reliable data depended on consistent timing of blood samples.

Low iron levels were associated with higher levels of Factor VIII, a blood protein which promotes normal clotting. This in turn was a strong risk factor for blood clots. Making the blood clot more easily after losing iron might be an evolutionary trick to aid survival, suggested Dr Shovlin.

She added: 'We can speculate that in evolutionary terms, it might be advantageous to promote blood clotting when your blood is low in iron, in order to prevent further blood loss'.


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