Table 2.
The subgroup analysis of studies reporting serum Mg levels in PD
| Subgroup | No of studies | SMD (95% CI) | Test of SMD =0 | Heterogeneity | ||
|---|---|---|---|---|---|---|
| Z | P for Z | I2 (%) | P for I2 | |||
| All studies | 12 | 1.09 (0.52, 1.66) | 3.76 | 0.000 | 95.6 | 0.000 |
| Location | ||||||
| Asia | 5 | 2.22 (0.82, 3.63) | 3.10 | 0.002 | 97.6 | 0.000 |
| Europe | 5 | 0.37 (−0.32, 1.06) | 1.06 | 0.289 | 91.6 | 0.000 |
| America | 1 | 0.08 (−0.33, 0.48) | 0.38 | 0.705 | – | – |
| Africa | 1 | 1.18 (0.80, 1.55) | 6.13 | 0.000 | – | – |
| Analysis method | ||||||
| ICP-MS/ICP-AES | 8 | 1.55 (0.54, 2.57) | 2.99 | 0.003 | 97.0 | 0.000 |
| AAS | 3 | 0.55 (−0.04, 1.14) | 1.84 | 0.066 | 88.2 | 0.000 |
| Colorimetry | 1 | 0.08 (−0.33, 0.48) | 0.38 | 0.705 | – | – |
Abbreviations: AAS, atomic absorption spectrometry; ICP-AES, inductively coupled plasma-atomic emission spectrometer; ICP-MS, inductively coupled plasma-mass spectrometry; PD, Parkinson’s disease; SMD, standardized mean difference.