Memory leaks in Qt Sql when executing a simple query

The following code uses Qt SQL version 4.9 with sqlite.

#include <QtSql>

int main(int argc, const char **argv) {
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("db.sqlite");
    db.open();
    QSqlQuery query;
    query.exec("CREATE TABLE test (test VARCHAR PRIMARY KEY);");
    db.close();
}

Valgrind gives me a leak report like this:

==2832== LEAK SUMMARY:
==2832==    definitely lost: 168 bytes in 3 blocks
==2832==    indirectly lost: 556 bytes in 9 blocks
==2832==      possibly lost: 0 bytes in 0 blocks
==2832==    still reachable: 51,660 bytes in 83 blocks

That is just a simple SQL query and I do not understand why there are so much leaks. These leaks are located in QLibrary and QFactoryLoader. Is there any way to clean the memory on application exit?