A continued reduction in first and second mortgage debt has kept overall consumer debt from growing in most major U.S. metro areas, according to the latest Equifax National Consumer Credit Trends Report.

Of the nation's largest 25 markets, just six experienced increases in total consumer debt through March 2015compared to the same period a year ago. The metro areas that posted increases included Houston (+4.4%), Dallas (+2.5%), Denver (+1.3%), Pittsburgh (+1.1%), Phoenix (+0.4%) and Portland (+0.07%).

If mortgages and home equity loans were not considered, however, every metro market would have shown an increase year over year, said Assad Lazarus, interim unit leader of Equifax Personal Information Solutions. Mortgages are a major driver of overall consumer debt because they typically are much larger in size than other consumer loans tracked in the report, including auto loans, retail credit cards and bank credit cards.

"The latest numbers show that while the mortgage market continues to heal, the overall appetite for debt is growing across the board as consumers continue to open their wallets," said Lazarus. "Every major city is exhibiting growth in non-mortgage debt, which is a reflection of the improvement in the U.S. economy."

Total consumer debt was $9.99 trillion in the first quarter, a slight decline from $10.1 trillion a year earlier, according to the Equifax report. Of the 19 metro areas that experienced decreases in total consumer debt, those with the largest declines were Miami (-3.6%), Los Angeles (-2.6%), Chicago (-2.5%), San Diego (-2.2%) and New York (-2.03%), all of which were due entirely to reductions in mortgage debt.

Many of those markets continue to work through a huge backlog of foreclosures that came during the Great Recession, said Lazarus. He noted that the only cities that saw an improvement in mortgage lending in the first quarter were Dallas, Denver and Houston – the same cities that topped the overall consumer debt list.