Study	Reason for exclusion
Arden 2006	Not all participants had chronic pain. Does not report on outcomes of vitamin D therapy
Björkman 2008	Pain not always self-rated (“self- or nurse-reported”). No other outcomes of interest
de Nijs 2006	Participants were not required to have chronic pain
Dottori 1982	Not explicitly described as double-blind
Grove 1981	Fluoride and calcium administered concurrently with calciferol but not given to comparator group
Krocker 2008	All patients received vitamin D. Described as “pseudorandomised”. Not described as double-blind
Lyritis 1994	Not clear that all participants had chronic pain
Ringe 2000	Not clear that all participants had chronic pain. Not described as double-blind
Ringe 2004	Not clear that all participants had chronic pain. Not described as double-blind
Ringe 2005	Not clear that all participants had chronic pain. Not described as double-blind. Reports on same results as Ringe 2004
Ringe 2007	Not clear that all participants had chronic pain. Not described as double-blind