Yep, my mother has it pretty severely; her case was a fairly simple fix; apparently her vitamin D pills weren't working because she has trouble absorbing it. So she was getting REALLY low every winter; now she goes in for shots and does supplemental vitamins (supposedly vitamin B complex will help her absorb the D properly?), and has a sun-lamp, and at least one weekend every winter she and my stepfather drive over the mountains somewhere where there's sun. It might be cold and snowy -but it's sunny. And they spend a lot of that time outdoors.

Those things together have really made a difference! Now she only has to deal with the arthritis.