Table 4. Subgroup analysis to investigate differences between studies included in meta-analysis.

Subgroup	Cohorts (n)	RR (95% CI)	Q	I2(%)	P value	P value for heterogeneity between subgroups
Dietary Magnesium Intake
Individual CVD outcomes
Stroke	7	0.87 (0.81, 0.93)	4.76	0	0.575
CHD	3	0.73 (0.60, 0.87)	3.63	17	0.305	0.060
CVD death	3	0.89 (0.79, 0.99)	10.95	73	0.012
Sex
Male	7	0.87 (0.74, 1.00)	14.34	58	0.026	0.048
Female	6	0.86 (0.76, 0.95)	6.79	26	0.237
Location
United States	8	0.80 (0.72, 0.88)	9.70	18	0.287
Europe	3	0.91 (0.83, 0.99)	4.84	59	0.089	0.050
Asian	2	0.87 (0.76, 0.97)	4.60	57	0.100
Distribution fractions
Quintile	8	0.87 (0.82, 0.93)	10.53	24	0.230	0.187
Quartile	4	0.74 (0.80, 0.90)	2.63	0	0.621
Serum Magnesium concentrations
Individual CVD outcomes
CVD & CHD	4	0.82 (0.73, 0.92)	6.82	41	0.145	0.021
CVD death	4	0.64 (0.52, 0.77)	0.42	0	0.935
Sex
Male & Female	6	0.79 (0.72, 0.88)	15.24	61	0.018	0.797
Only male	2	0.75 (0.44, 1.06)	0.55	0	0.458
Location
United States	6	0.80 (0.73, 0.88)	13.81	49	0.055	0.075
Europe	2	0.78 (0.71, 0.81)	0.00	0	1.000
Distribution fractions
Quartile	5	0.84 (0.75, 0.92)	0.09	46	0.087	0.069
Thirds	2	0.67 (0.52, 0.83)	11.04	0	0.766