Comparison 2. Adverse effects of treatment, magnesium versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Withdrawals due to adverse events	4	201	Risk Difference (M‐H, Fixed, 95% CI)	‐0.03 [‐0.10, 0.03]
1.1 Idiopathic cramps (largely older adults)	2	86	Risk Difference (M‐H, Fixed, 95% CI)	0.02 [‐0.06, 0.11]
1.2 Pregnancy‐associated leg cramps	2	115	Risk Difference (M‐H, Fixed, 95% CI)	‐0.07 [‐0.17, 0.02]
2 Number of subjects with major adverse events	2	91	Risk Difference (M‐H, Fixed, 95% CI)	‐0.02 [‐0.10, 0.05]
2.1 Idiopathic cramps (largely older adults)	1	46	Risk Difference (M‐H, Fixed, 95% CI)	‐0.05 [‐0.16, 0.07]
2.2 Pregnancy‐associated leg cramps	1	45	Risk Difference (M‐H, Fixed, 95% CI)	0.0 [‐0.08, 0.08]
3 Number of subjects with minor adverse events	1	45	Risk Difference (M‐H, Fixed, 95% CI)	‐0.01 [‐0.27, 0.25]
3.1 Idiopathic cramps (largely older adults)	0	0	Risk Difference (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
3.2 Pregnancy‐associated leg cramps	1	45	Risk Difference (M‐H, Fixed, 95% CI)	‐0.01 [‐0.27, 0.25]