Disability insurers may be getting slightly fewer long-lasting claims for bad backs and somewhat more for conditions related to childbearing.

Researchers at Unum, Chattanooga, Tenn., have published statistics hinting at that conclusion in an analysis based on 2006 data for 178,000 employer policyholders and 27 million covered employees.

Cancer remained the leading cause of long term disability claims, accounting for about 12% of LTD claims, Unum researchers report.

The share of LTD claims resulting from back injuries fell to 8%, from 9% in 2005, but the share resulting from pregnancy increased to almost 12%, from 10%.

Short-term disability claim figures for normal pregnancy were mixed. The share of STD claims resulting from normal pregnancy was up from 18% in 2005 but down from 21% in 2004.

In a related analysis, Unum researchers have found a 96% increase in return to work for breast cancer claimants on short-term disability, and a 14% increase for claimants on long term disability.

Similarly, the researchers have found a 72% increase in return to work for prostate cancer claimants on short-term disability, and a 36% increase for claimants on long-term disability.