QFontDatabase::findFont really slow on OS X

When starting a Qt application on OS X Mavericks, QFontDatabase::findFont is so slow, that the whole application takes at least a second to start up on my machine. As you can see in the attached screenshot, ~840ms of this second is spent directly in QFontDatabase::findFont.

The problem is reproducible on my machine, by creating an empty "Qt Widgets Application" via QtCreator's New Project wizard.
It is much more severe in applications which use QPainter::drawText a lot (e.g. 2.7 seconds in findFont alone).

By the way: It is not at all important, from where findFont is called. In the attached screenshot it is QStatusBar, for other applications it is some QStyledItemDelegate or QLabel. This might suggest, that the first few calls to findFont are slow, or something else in this direction.