Possible rare disease cluster among Wittenoom woman
Researchers have detected a possible cluster of rare placental disease among the women and girls exposed to crocidolite at Wittenoom in Western Australia.
There were three cases of choriocarcinoma (plancental cancer) and three cases of hydatidiform mole (an abnormal uterine growth) among the 2,968 Wittenoom women, at least four of whom lived with mine workers who brought their asbestos-laden work clothes home to be washed.
These diseases are part of a spectrum of disorders known as gestational trophoblastic diseases (GTD), which are extremely rare. Usually, about six cases of choriocarcinoma and 500 hydatidiform moles are diagnosed nationwide per year.
The research team, led by Dr Alison Reid, point out that asbestos fibres have been found in the human ovary and the placental digests of infants.
They suggest, therefore, that their findings warrant further research on possible links between asbestos and GTD.
(Cancer Epidemiological Biomarkers Prevention, 2009)
Reproductive cancers in the Wittenoom women
An analysis of cancers of the reproductive system among the 2,968 women and girls who lived at Wittenoom has found no consistent evidence of a link with asbestos exposure.
Researchers, led by Dr Alison Reid, examined the incidence of ovarian, cervical, uterine and breast cancer among the women.
They found that the incidence of ovarian, cervical and uterine cancer was not significantly higher among the Wittenoom women compared with the Western Australian population.
Among the 400 women who worked at the mine site, the cervical cancer rate was twice that of the WA population, but the ovarian cancer rate was lower than the WA rate.
Women who lived with, or washed the clothes of, mine workers did not show an increased risk for any of the gynaecological cancers or breast cancer.
(Cancer Epidemiological Biomarkers Prevention, 2009)GP
Rising mesothelioma toll among Wittenoom women
Researchers predict that deaths from malignant mesothelioma among the 2,968 women who lived at Wittenoom will rise until 2030.
There were 40 deaths from mesothelioma among these women until 2004.
Using a range of models that incorporated time since first asbestos exposure, risks from other diseases, latency periods and clearance of fibres from the lungs, the researchers predict that there will be another 66 to 87 deaths from mesothelioma in the next 20 years.
This is 1.5 to 2.5 times higher than the number of cases of the disease already diagnosed to the end of 2004.
(Occupational Environmental Medicine, 2009)
Mortality of the Wittenoom workers
A follow-up study of the 6,493 men who worked at the Wittenoom mine and mill has found there were 190 diagnoses of pleural and 32 cases of peritoneal mesothelioma until 2004.
Asbestos-related diseases continued to be the main causes of excess mortality among the former workers, with the proportion of mesothelioma increasing with increasing time since first exposure to asbestos.
Researchers, led by Professor Bill Musk, also found that the men suffered higher than average deaths from lung cancer, pneumoconiosis (lung disease caused by dust inhalation), respiratory diseases, tuberculosis, digestive diseases and alcoholism when compared to the Western Australian male population.
(Occupational Environmental Medicine, 2008)
Respiratory cancer among the women of Wittenoom
Forty years after the asbestos mine at Wittenoom closed, there is a high toll from respiratory cancer among the 2,968 women who lived and worked there.
Researchers have found there were 47 cases of mesothelioma and 55 cases of lung cancer among the 437 different cancers diagnosed in the Wittenoom women from 1960 to 2005.
When compared to the WA female population, Wittenoom women and girls had higher rates of both mesothelioma and lung cancer.
(International Journal of Cancer, 2008)
Deaths of Wittenoom women exposed to asbestos in the environment
A study of the Wittenoom women who were not directly involved in mining and milling asbestos has found a high incidence of deaths from cancer compared with the Western Australian female population
Among the 2,552 women and girls who lived in town between 1943 and 1992 but did not work for Australian Blue Asbestos, there were 425 deaths, including 30 from malignant mesothelioma.
Researchers, led by Dr Alison Reid, found that these women had excess mortality from all cancers, including lung cancer, as well as pneumoconiosis (lung disease caused by dust inhalation).
They concluded that environmental exposure to asbestos had an impact on the cause of death of the women.
(Occupational Environmental Medicine, 2008)
The affect of asbestos on Wittenoom children
A study of the 4,768 residents of Wittenoom has found children were less likely than adults to contract mesothelioma.
Researchers found that although all residents of the town had a much higher incidence of mesothelioma when compared to the general population, the rate was 40 per cent lower in those first exposed to asbestos as children compared with those exposed after the age of 15.
In keeping with the disease’s long latency period, the youngest former resident to be diagnosed with the disease was 26.
The researchers suggested that this reduced risk could be the result of children having more efficient biological defence mechanisms than older people.
Although the mesothelioma mortality rate was consistently lower for women than men, women had a steeper dose-response curve, which suggests increased susceptibility to asbestos compared with men.
This difference could have a physiological or biological basis, with women generally having smaller lung volume than men.
(Chest, 2007)
Mesothelioma link with asbestosis
Researchers have found a link between benign pleural disease – or asbestosis –
and peritoneal mesothelioma.
A team led by Professor Bill Musk studied the medical histories of 1,988 former Wittenoom residents taking part in a cancer prevention study (formerly the Vitamin A program). Between 1990 and 2002, there were 76 cases of mesothelioma, 56 of the pleura and 20 of the peritoneum.
They found that people with mesothelioma of the peritoneum had more radiographic evidence of benign pleural disease and pleural thickening than non-cases.
There was, however, no link found for pleural mesothelioma. (Occupational Environmental Medicine, 2005)
The effect of asbestosis on lung cancer risk beyond the impact of asbestos alone
Researchers have determined that asbestosis does not necessarily lead to lung cancer in people with known exposure to crocidolite.
A team led by Dr Alison Reid studied the medical records of 1,988 former Wittenoom residents enrolled in a cancer prevention program (formerly the Vitamin A program).
Between 1990 and 2002, there were 58 cases of lung cancer, but researchers found smoking remained the strongest predictor of lung cancer.
While there was an increased risk of lung cancer with increasing exposure to asbestos, the team concluded that lung cancer can develop with or without the presence of asbestosis.
(Occupational Environmental Medicine, 2005)
Study finds no link between asbestos and aerodigestive cancers
A study of 2,400 former Wittenoom workers whose smoking habits were followed from 1979 has found no significant link between asbestos exposure and cancers of the upper (lip, mouth, tongue, pharynx, larynx and maxillary sinus) and lower (oesophagus, stomach and colon and rectum) aerodigestive tract.
There were 129 cases of these cancers and 57 deaths among the cohort of former workers.
Although the workers showed a significantly higher risk of dying from upper aerodigestive cancers than the Western Australian male population, this was associated with smoking habits, not asbestos exposure in Wittenoom.
The research team, led by Dr Alison Reid, pointed out that although the study had the benefit of very comprehensive smoking information, it was limited by the fact that it did not include the entire Wittenoom workforce.
(International Journal of Cancer, 2004)
Malignant mesothelioma in Wittenoom workers until 2000
Researchers found the total number of mesothelioma diagnoses in former Wittenoom workers to the end of 2000 was 235 in men (202 pleural, 33 peritoneal) and seven (all pleural) in women.
By the end of 2000, 231 of these people had died from the disease.
(Occupational Environmental Medicine, 2004)
By Catherine Madden