* Debt-to-income ratio 165.0 pct in Q4 vs 164.7 pct in Q3
* Increase much smaller than in previous quarters
* Data shows housing, borrowing starting to cool
OTTAWA, March 15 Canadian households increased their debt load for the third consecutive quarter, keeping the debt-to-income ratio at an all-time high of 165.0 percent, although it rose much less than the previous quarters, according to Statistics Canada data on Friday.
Soaring personal debt has been a top concern of Canadian policymakers as consumers take out mortgages at ultra-low rates to buy homes in a heated real estate market.
The Bank of Canada in January predicted the trend growth in household credit would moderate and the debt-to-income ratio would stabilize at around current levels.
The debt-to-income ratio rose 0.3 percentage points in the fourth quarter from 164.7 percent in the third, much smaller than 1.5 and 1.6 point increases in the previous two quarters.
Statscan said household debt and income rose at roughly the same rate in the fourth quarter.
Households' credit market debt, which includes mortgages, consumer credit and loans, rose by C$14.7 billion in the quarter, about half the increase seen in the third, Statscan said.
Mortgage borrowing led the demand for credit in the fourth quarter, rising by C$11 billion to a total of C$1.1 trillion. In the previous quarter, mortgage borrowing increased by C$19.1 billion.
Consumer credit debt stood at C$477 billion at the end of 2012.
Worried about stretched personal finances and high housing prices, Canada's federal government tightened mortgage lending rules four times in the last four years to make it harder for home buyers to take on too much debt in their quest for a home.
The rule changes gradually shorted the maximum mortgage length from 40 years to 25 and put limits on how much people can borrow against their homes, among other measures.
While interest rates are not expected to rise until 2014 - the stiffer lending rules and government warnings about the high debt loads of Canadian households have helped cool the ardor of home buyers, with the hottest markets, including Vancouver and Toronto, feeling a chill.
The growth of household credit slowed to about 3 percent near the end of 2012, the lowest rate since 1999, and down from about 5.5 percent through much of the remainder of last year, according to the central bank.