Search NIOSH  |  NIOSH Home  |  NIOSH Topics  |  Site Index  |  Databases and Information Resources  |  NIOSH Products  |  Contact Us

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.

LTAS Home

Documentation