Table 6.

The summary of conclusions from the studies of multiple sclerosis (MS) patients included in the systematic review accompanied by the assessment of the quality of studies based on the design of the studies and the Newcastle-Ottawa Scale (NOS) score.

Ref.	Studied Outcome	Conclusion about General Influence of Vitamin D on Mental Health a	Quality of the Study Based on the Study Design b		Quality of the Study Based on the NOS Score c
[35]	Quality of life	Supporting	Randomized against placebo	+++	8	+++
[36]	Depressive symptoms; fatigue	Not supporting	Randomized against placebo	+++	6	++
[37]	Depressive symptoms	Supporting	Prospective with supplementation applied	++	5	++
[38]	Quality of life; fatigue	Supporting	Prospective with supplementation applied	++	6	++
[39]	Depression	Not supporting	Prospective based on self-reporting	+	7	+++
[40]	Quality of life	Supporting	Prospective based on self-reporting	+	6	++

^a Conclusions: supporting—major conclusion of the study indicating potential positive influence of vitamin D on mental health of MS patients; not supporting—major conclusion of the study indicating no positive influence of vitamin D on mental health of MS patients; ^b Quality of the studies: +++ for studies randomized against placebo; ++ for prospective studies with supplementation applied (intervention); + for prospective studies based on self-reported supplementation; ^c Quality of the studies: +++ for low risk of bias (7–9 NOS points); ++ for high risk of bias (4–6 NOS points); + for very high risk of bias (0–3 NOS points).