Growing up near livestock farm raises cancer risk

The research findings published online in Occupational and Environmental Medicine suggest that children raised on livestock farms are at greater risk of developing blood cancers -- such as leukemia, multiple myeloma and non-Hodgkin's lymphoma, as an adult.

Scientists in New Zealand found that the risk was greatest among those who had grown up on a poultry farm.

In their study, experts at Massey University in New Zealand found that kids exposed to livestock farm were at three times higher risk of developing a blood cancer in the later part of their life.

Study details
To reach their findings, Andrea 't Mannetje, of the Centre for Public Health Research at Massey University in Wellington, New Zealand, and colleagues compiled information from 114,000 death certificates for people between 35 and 85 years of age who died between 1998 and 2003 in New Zealand.

The analysis of the data showed that during the study period, just over 3,000 deaths were attributed to blood cancers.

After looking at their jobs and those of their parents, the researchers found that growing up on a livestock farm was linked to a higher risk.

More precisely, the risk of developing a blood cancer was 22 percent higher for those who grew up on a livestock farm than those who did not.

Risk was greatest among those who exposed to poultry farms
Being raised on a poultry farm was associated with a higher risk of developing such a cancer, the researchers noted. The risk of developing a blood cancer was three times as high for those who had spent their childhood living on a poultry farm.

On the other side, the investigators found that growing up on an arable/crop farm conferred an almost 20 percent lower risk of developing a blood cancer, but crop farming as an adult was associated with an almost 50 percent increased risk.

More research needed to establish the link
The reports' authors said that one possible explanation for these findings could be that exposure to pesticides or infections as a result of contact with farm animals in childhood may alter the immune system response, thereby triggering the risk of blood cancer in later life.

However, they said further research was needed before a "definitive cause and effect" could be established.

The researchers said: “The study corroborates earlier findings that crop farming is a risk factor for haematological cancer, and suggests that of the different livestock production sectors, beef cattle farming in particular is associated with haematological cancer.

“The increased haematological cancer risk we observed for parental occupation in livestock farming suggests that exposure to farm animals during childhood, in particular poultry, may increase the risk of haematological cancer in adulthood.

“This may be through, for example, exposure to specific viruses or other biological exposures that indirectly increase haematological cancer risk by modulating the immune system.

“Additional studies are needed to further investigate this hypothesis.”

The study authors reported their findings on the British Medical Journal's website on Wednesday (28 July).