Table 1
GWAS data source publications and sample sizes of tested phenotypes.
| TRAIT | PUBLICATION DATE | REFERENCE NUMBER | NUMBER OF CASES | NUMBER OF CONTROLS |
|---|---|---|---|---|
| Essential Tremor | 2024 | [6] | 16,480 | 1,936,173 |
| Bipolar Disorder | 2021 | [64] | 41,917 | 371,549 |
| Cigarettes per Day | 2022 | [65] | 784,353 | |
| Coffee Consumption | 2019 | [66] | 358,093 | |
| Cognition | 2024 | [67] | 455,496 | |
| Alcohol Consumption (Drinks per Week) | 2022 | [65] | 2,965,643 | |
| Essential Hypertension | 2019 | [66] | 99,665 | 289,307 |
| Hearing Loss | 2019 | [66] | 96,354 | 274,359 |
| Insomnia | 2022 | [68] | 593,724 | 1,771,286 |
| Low-Density Lipoprotein (LDL) Levels | 2021 | [69] | 1,320,016 | |
| Major Depressive Disorder (MDD) | 2019 | [70] | 246,363 | 561,190 |
| Parkinson’s Disease | 2019 | [71] | 39,275 | 1,411,006 |
| 25-OH Vitamin D Levels | 2023 | [72] | 421,867 |
[i] *For multi-ancestry GWASes, the European ancestry cohort of the population was extracted, and reported sample sizes are from exclusively that subset.
Figure 1
Bidirectional Mendelian randomization results for essential tremor with all phenotypes . The forest plots depict Mendelian randomization (MR) analyses results when (A) essential tremor is the exposure with all other traits as outcomes, and MR results when (B) all other traits are the exposure and essential tremor is the outcome. Mendelian randomization analysis method results are shown separately by color.
Table 2
Number of instrumental variables retained by test and significant results.
| EXPOSURE | OUTCOME | NUMBER OF IVS RETAINED | NOMINALLY SIGNIFICANT RESULTS |
|---|---|---|---|
| Essential tremor | Bipolar disorder | 27 | N/A |
| Bipolar disorder | Essential tremor | 58 | N/A |
| Essential tremor | Cigarettes smoked per day | 27 | N/A |
| Cigarettes smoked per day | Essential tremor | 56 | N/A |
| Essential tremor | Coffee consumption | 26 | N/A |
| Coffee Consumption | Essential tremor | 34 | N/A |
| Essential tremor | Cognition | 21 | N/A |
| Cognition | Essential tremor | 50 | N/A |
| Essential tremor | Drinks (alcohol) consumed per week | 27 | N/A |
| Drinks (alcohol) consumed per week | Essential tremor | 83 | MR Egger (p = 4.72e-02) |
| Essential tremor | Essential hypertension | 27 | N/A |
| Essential hypertension | Essential tremor | 165 | N/A |
| Essential tremor | Hearing loss | 27 | N/A |
| Hearing loss | Essential tremor | 30 | N/A |
| Essential tremor | Insomnia | 12 | N/A |
| Insomnia | Essential tremor | 7 | N/A |
| Essential tremor | low-density-lipoprotein levels | 25 | N/A |
| low-density-lipoprotein levels | Essential tremor | 438 | N/A |
| Essential tremor | Major depressive disorder | 24 | N/A |
| Major depressive disorder | Essential tremor | 32 | N/A |
| Essential tremor | Parkinson’s disease | 25 | Inverse variance weighted (p = 5.06e-03) |
| Parkinson’s disease | Essential tremor | 23 | N/A |
| Essential tremor | 25-OH Vitamin D | 27 | N/A |
| 25-OH Vitamin D | Essential tremor | 122 | MR Egger (p = 4.72e-02) |
Figure 2
Structural Equation Model of ET and associated traits. The figure depicts the interactions between unobserved latent variables (shown in ellipses) and observed phenotypes (in squares). Unidirectional arrows from latent variables to traits represent the loading of the phenotype onto the factor, with loading coefficients written on the arrow, and standard deviations in parentheses underneath. The portion of variance in the trait unexplained by its loading on to the factor is found on the double-barbed curved arrows pointing from the trait to itself, with standard deviations in parenthesis. Finally, the curved arrows between latent variables represent the degree of interaction between latent variables, with standard deviations in parenthesis. The model metrics (CFI and SRMR) are shown in the top left corner.