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December 2010 - A major new version of LTAS.NET (ver. 3.0.3) was released. This version includes numerous changes summarized below. A full description of the changes is available in “ Major changes in LTAS 3.0” on the Downloads page.

Before installing LTAS.NET 3.0, please keep in mind the following information:

• The first time you install LTAS.NET 3.0, you must install the full version, not the upgrade version, even if you previously had a version of LTAS.NET on your computer. This is because we have improved the SQL Server database engine. Note that in future minor releases, you will be able to install an “upgrade” version.
• When you install the full version, if you are working on a limited-access account, your IT administrator will need to install it for you. Please see the “downloads” page of the NIOSH/LTAS website for more information.
• LTAS.NET 3.0 supports Windows XP, Vista, and 7 operating systems. If you install LTAS.NET 3.0 on an XP system that already has a previous version of LTAS.NET, you will notice that LTAS.NET 3.0 is installed side-by-side with your previous version of LTAS. You may use either version on a PC running XP; however, we recommend transitioning to LTAS.NET version 3.0 as soon as possible.
• In LTAS.NET 3.0, you can also open projects from the previous version of LTAS and save them in the new version.
• If you have special rate files that you've created in the previous version, you will need to create a new version that is compatible with LTAS.NET 3.0, using the instructions in the LTAS users guide that is installed with the program.

LTAS.NET 3.0 Enhancements:

• Support for Windows Vista and Windows 7
• New rate file features
• The cause map and the rate file have been merged into a single file and rate files are easier to manage.
• Updated US underlying and multiple-cause rates and proportions through 2007.
• Changes affecting software functionality
• Support for reporting p-values in SRR and SMR reports.
• Changed the ordering of fields in the Import Wizard drop-down menu.
• Changed the ordering of fields in the Import Options report so that they are ordered by column position.
• Changes affecting software usability
• Updated Report Viewer to use SQL Server Reports, resulting in better export capabilities.
• Updated Database Engine to use SQL Server 2005, doubling the storage capacity from 2GB to 4GB.
• User documentation is now section 508 compliant.
• Changes to improve reports and data export capabilities
• Inclusion of Supermajor (“All Causes” and “All Cancers”) and Major cause-of-death categories in cohort export file.
• Added a new capability in Stratify, allowing user to report or export the Post-Stratify Personal Cumulative Dose for each subject, which will give lagged cumulative exposures.
• Changed analysis reports so that exposure lag information is included with the page variables.

There were also numerous bug Fixes since 2.0.16:

• Changed the way exposure lag time is calculated so that zero lagged cumulative exposure beyond the lag time period is appropriately mapped to the lowest exposure category.
• Corrected a problem with person-time prior to achieving minimum exposure not being discarded.
• Updated Stratify Reject report, export and progress dialog to account for person-time that is discarded.
• Increased timeout values on all database queries to prevent timeouts on large studies.
• Corrected a problem that caused stratify to fail if too many stratifier variables were selected. While a limit still exists, it is larger (see documentation for details).
• Resolved Stratify issue that caused the wizard to fail when selecting a global categorical and no exposure agent.
• Added validation to the Import Wizard to prevent duplicate names from being used for exposure agents, temporal categoricals, fixed stratifiers or global categoricals.
• Resolved issue with exporting observed deaths and diagnosis for MCOD studies that caused the export file to be empty.
• Enhanced the import data validation to reject history records with invalid exposure agent values.

October 2008 - A new version of LTAS.NET (ver. 2.0.16) was released. This version includes the following changes:

• A table that shows the relationship between rate file and outcome file options has been added to the 'Outcome Import File' section of the documentation.

• Corrected upgrade installation to properly restore custom rate files and cause maps. Custom rate files that were imported before an upgrade to a new version of LTAS.NET did not work properly under the following conditions:

• The custom rate file referenced a custom cause map
  
  
• Two or more custom cause maps were imported prior to the upgrade
  
  
• The custom cause maps were imported in an order other than alphabetical order.

After upgrading, users should re-import any custom rate files they are using. Even though the problem is now fixed and won't occur as a result of upgrading to this release, re-importing will eliminate the effects of previous upgrades.

• Corrected Personal Cumulative Dose report to show correct person time in diagnosis-based studies for persons having multiple history records. For diagnosis-based studies, the Personal Cumulative Dose report was incorrectly including time after the date of diagnosis. This problem was specific to the Person Cumulative Dose report and did not affect any other reports including analysis reports.

• Updated NIOSH-119 rates and cause map

The NIOSH-119 UCOD and Proportion rate files have been updated with rate data for years 2003-2005. The LTAS.NET state rates have also been updated with the additional years of data. Additionally, the NIOSH-119 cause map file has changed slightly to correct the mapping for COPD in ICD Revision 8 along with a couple other minor re-mappings affecting Minors 64, 73 and 119.

• Added support for diagnosis-based (i.e., incidence) studies
• Changed import validation logic to properly handle diagnosis-based studies.

See the Outcome File Requirements section in the LTAS.NET User's Guide for details.

• For studies using diagnosis based rates, modify Stratify to include diagnosis for non-deceased persons.
• Added ability to export observed diagnosis for studies that use diagnosis-based rates.
• Corrected end of risk accumulation logic for diagnosis-based studies

Time at risk should not accumulate past the date of diagnosis for diagnosis-based studies. In addition to correcting the logic, the import wizard was changed to clarify the end of risk options for diagnosis-based studies.

• Fixed problem causing incorrect results in SRR reports when all causes are selected

Selecting all causes for an SRR report caused incorrect results. In many cases, the same results were mistakenly reported for each cause.

• Added support for revisions in non-ICD cause maps

Studies that are based on non-ICD codes can specify either a global revision or specify the revision in the outcome file.

• Corrected inconsistent calculation error when running Major/Minor Summary report.

This removed an error message received when running a Major/Minor Summary report or any variant of an SMR List report that included Cause as the row variable.

A more detailed description of these changes along with installation instructions can be found in the ReadMe.txt file on the Downloads page.
In addition, the LTAS.NET FAQ and USER Manual documents have been updated.
Finally, the MCOD rates are now available for download. A separate mapping file is needed because these rates are still using the 1960-2002 data. They will be updated in the future to include the 2003-2005 data.

February 2008 A new version of LTAS.NET (ver. 2.0.8) was released. This version corrects the following problems that had been identified in interim versions:

• Fixed problem in person-year and event allocation for exposures occurring before follow-up time begins when a lag is also used.
• Fixed problem with SMR analysis reporting incorrect expected and observed values in some situations.
• Fixed rounding problem when stratifying Duration categories using Years for units.
• Fixed errant warnings in Import Exception reports when a global risk begin date is used.
• Modified 119 Mapping files to fix minor errors.

A more detailed description of these changes along with installation instructions can be found in the ReadMe.txt file on the Downloads page.

In addition, the LTAS.NET FAQ document has been updated and the PC-LTAS state rates have been updated to the comparable LTAS.NET versions. Note that if you wish to use PC-LTAS state rates, you will have to pre-map the causes of death in your demographic file to the minor number (this is not necessary in LTAS.NET).

October 2007 - Special neurodegenerative disease mortality rate files have been prepared for LTAS.NET and are now available on the download page. These files represent US UCOD rate data between 1960 and 2002. There are four neurodegenerative mappings [Dementia & Alzheimer's excluding Arteriosclerosis dementia, Arteriosclerosis dementia, Amyotrophic Lateral Sclerosis (ALS), and Parkinson's Disease] and one "other cause" mapping. The four neurodegenerative mappings are grouped under a super major similar to the Cancer mappings in the 92 and 119 rate files. When you import these rates into LTAS.NET remember to import the Cause Map Definition file first and then the Rate Data file; otherwise the Rate Data import will fail.

September 2007 - A new version of LTAS.NET (ver. 2.0.1) was released. This version corrects two bugs: One bug occurred in Stratify for studies that have person-time and deaths extending beyond the last date for which rates are available (12/31/2004). If users included data beyond this date, the bug caused Stratify to crash the first time it encountered such a date. This bug was fixed by applying the rates from the previous five-year category to any person-time and events that occur after the end date of the rate files, based on the user-specified end of study date (up to five years beyond the last rate end date). The second bug affected only studies that imported time-since-last-exposure (TSLE) but not time-since-first-exposure for the exposure variable, and it caused TSLE to be inappropriately classified.

August 2007 - .NET ® VERSION - The new Windows-based version of LTAS, called LTAS.NET, is now available for download. The software is more interactive and provides greater flexibility for data input, export, and analysis. Visit the documentation page to learn more. The U.S. underlying cause ratio and proportions are provided with LTAS.NET. Visit the download software page and download individual state rate files.

Objectives in creating LTAS.NET

• Create a stable, user-friendly and reliable NIOSH life table analysis system for the Windows environment, as the DOS environment has become unreliable
• Add features requested by users to increase utility of the program
• Correct minor discrepancies noted in date handling and some statistical calculations within PC-LTAS

Major new features of LTAS.NET

• User can stratify on and analyze
  • Two or more time-varying exposures simultaneously
  • User-defined fixed and time-dependent covariates
  • A global date for all persons in the cohort
  • Active employment status (with a user-defined lag for inactive status) to evaluate the healthy worker survivor effect
• LTAS.NET has more flexible import, analysis and reporting options
• User can export stratified event and person-time data for Poisson regression analysis

The PC-LTAS version is no longer available for download; however, the PC-LTAS Rates will remain available until further notice.

June 2006 - Rate File Information - The Tenth Revision of the International Classification of Diseases (ICD-10) was recently adopted. To make use of the ICD-10 for the purpose of identifying disease-exposure associations, NIOSH has designed new updates to the life table rate file which are currently being applied to the U.S. rates used for life table analyses. This paper describes the changes to existing rates, and the addition of new cause of death categories including mesothelioma, cancer of the pleura, COPD, unintentional injuries, and terrorism.

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