Incidence of Malignant Mesothelioma

chest xrayMesothelioma is a rare and usually fatal cancer of the lining of the chest (pleura) or abdomen (peritoneum).  The great majority of cases are attributable to asbestos exposure in the workplace, although some cases have been associated with environmental exposures.  In contrast to lung cancer -- another cancer that can be caused by asbestos -- mesothelioma is not associated with smoking. While many occupations have had potential exposure to asbestos and are an increased risk of mesothelioma, occupations categorized as high risk include plumbers, pipefitters, steamfitters, electricians, shipyard workers, railroad workers, and construction workers. 

Mesothelioma has a long latency period, typically occurring 20 to 50 years after asbestos exposure.  The median age at diagnosis in Minnesota is 72 for both males and females, while the age range is from 26 to 97.  Mesothelioma rates in Minnesota are over four-fold higher in males than females, reflecting differences in past employment in industries and occupations with asbestos exposure. Family members of asbestos-exposed workers may be exposed through clothing or footwear contaminated with asbestos fibers. 

Minnesota Issues

Taconite pellets from iron ore mining and processing, ready for shipment to steel mills.Concerns about mesothelioma risk in Minnesota have primarily focused on several industries and communities in northeastern (NE) Minnesota.  A two-fold excess of mesothelioma among males in that region (seven-county “Arrowhead” region) was identified in a 1997 analysis of cancer rates and trends. Two of the NE counties are among the highest 25 counties in the U.S. for mesothelioma mortality rates for 2000-2009. Carlton County ranks 3rd highest with an age-adjusted annual rate of 55.1 deaths per million population while St. Louis County ranks 21st with a rate of 25.1 deaths per million. The U.S. average during that period was 11.1 mesothelioma deaths per million. Subsequent analyses and record-linkage studies using existing employee records identified mesothelioma cases among employees of two large NE industries: the Minnesota taconite (iron ore) mining industry and a ceiling-tile manufacturing plant that used asbestos as a component of the tiles. Those studies and reports can be found on the Reports page under Respiratory Disease at this web site.  State-funded studies of mesothelioma and other health outcomes among Minnesota taconite miners have been underway since 2007 by the University of Minnesota School of Public Health and preliminary results were announced in April 2013. Information about that investigation can be found at the Minnesota Taconite Workers Health Study page.

Mesothelioma Rates and Trends

This indicator is based on data from the Minnesota Cancer Surveillance System (MCSS) at the Minnesota Department of Health (MDH).  The MCSS is a state-cancer registry that collects information on all newly-diagnosed cancers (cancer incidence) among state residents. All cases between the years 2000 and 2010 residing in the state of Minnesota were counted for the indicator. Additional years of data from MCSS are also shown when examining longer term trends. For comparison, data from three additional sources are shown: national mortality data for mesothelioma, state mortality data, and cancer incidence data from 13 other cancer registries in the U.S. that have part of the U.S. SEER program since 1992 or earlier.

Numbers and Age-Adjusted Rates of Mesothelioma Deaths, Minnesota vs U.S., 1999-2010

Year MN Deaths MN Rate per Million U.S. Deaths US Rate per Million
1999 61 16.64 2,484 11.53
2000 59 15.62 2,531 11.59
2001 45 11.86 2,509 11.34
2002 49 12.72 2,573 11.44
2003 72 18.1 2,625 11.47
2004 59 14.87 2,657 11.44
2005 46 11.18 2,704 11.42
2006 55 13.68 2,588 10.83
2007 32 7.85 2,606 10.66
2008 45 10.46 2,711 10.9
2009 61 14.41 2,753 10.86
2010 43 9.9 2,745 10.68
Data Source: National Occupational Respiratory Mortality System

Mesothelioma Mortality Rates, Minnesota vs U.S., 1999-2010

This graph shows the age-adjusted mortality rate of  mesothelioma cases per million residents > 15 years of age for Minnesota and  the United States beginning in the year 1999 and ending in the year 2010.  In 1999 Minnesota had a mortality rate of  16.64 Mesothelioma deaths per 1 million residents > 15 years of age, and the  United States mortality rate was 11.53 mesothelioma cases per 1 million  residents > 15 years of age.  In 2010  Minnesota had a mortality rate of 9.9 mesothelioma deaths per 1 million  residents >15 years of age and the United States had a mortality rate of  10.68 mesothelioma deaths per 1 million residents >15 years of age.  The graph depicts the flat trend for both the  Minnesota and United States rates.  All  data points can be found in table: Numbers and Age-Adjusted Rates of  Mesothelioma Deaths, Minnesota vs. U.S., 1999 – 2010.

Number of Newly-Diagnosed Mesothelioma Cases in Minnesota, 2000-2011

Year Total Males Females
2000 72 58 14
2001 47 40 7
2002 66 52 14
2003 70 53 17
2004 66 48 18
2005 65 49 16
2006 65 42 23
2007 58 47 11
2008 74 61 13
2009 50 38 12
2010 77 57 20
2011 81 61 27

Annual Number of Incident Mesothelioma Cases in Minnesota, 2000-2011

Incident number of mesothelioma cases in Minnesota, data in table above

Annual Number of Incident Mesothelioma Cases in Minnesota by Gender, 1988-2011

The number of new mesothelioma cases by gender per year in Minnesota

Annual Incidence Rate of Mesothelioma in Minnesota and the United States by Gender, 1992-20011

Incident mesothelioma cases by gender comparing Minnesota to the Nation

Annual Age-Adjusted Incidence Rates of Mesothelioma among Males by Region, 1992-2011

Incidence of mesothelioma for males comparing Northeast Minnesota, Minnesota, and the Nation

Number of Fatal Occupational Injuries Compared to the Number of Mesothelioma Cases, 1991-2011

Comparison of the number of fatal injuries to the number of mesothelioma cases annually in Minnesota

A comparison of the number of fatal occupational injuries compared to the number of new mesothelioma cases in Minnesota over the past 20 years demonstrates that the number of individuals newly diagnosed with mesothelioma is very similar to the number of fatal occupational injuries that occur in a year.

Trends

Trend analysis reveals that between the years 2000 to 2009 the incidence rate of malignant mesothelioma in Minnesota has neither increased nor declined.  Despite the dramatic decline in asbestos use in the U.S since the early 1970s (down from 800,000 metric tons in 1973 to 1,100 tons in 2012) and implementation of more protective occupational health standards, asbestos remains present in millions of homes, offices, and industries and represents an ongoing potential exposure hazard to both workers and the public.  The continued tracking of this disease will be necessary to ensure that prevention measures have been successful and to identify any emerging hazards or at risk populations.

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Updated Monday, November 24, 2014 at 02:21PM