

# Two sample MR report

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## Phosphatidylcholine (18:0_20:3) levels against Malignant_melanoma_of_skin

Date: **04 January, 2026**

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### Results from two sample MR:


|method                    | nsnp|         b|        se|      pval|
|:-------------------------|----:|---------:|---------:|---------:|
|MR Egger                  |    3| 0.5234128| 0.2680019| 0.3012634|
|Weighted median           |    3| 0.2180163| 0.0845451| 0.0099174|
|Inverse variance weighted |    3| 0.2205156| 0.0720522| 0.0022097|
|Simple mode               |    3| 0.1760112| 0.1155723| 0.2672167|
|Weighted mode             |    3| 0.2089531| 0.1131837| 0.2061526|

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### Heterogeneity tests


|method                    |        Q| Q_df|    Q_pval|
|:-------------------------|--------:|----:|---------:|
|MR Egger                  | 0.447781|    1| 0.5033906|
|Inverse variance weighted | 1.824667|    2| 0.4015860|

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### Test for directional horizontal pleiotropy


| egger_intercept|        se|      pval|
|---------------:|---------:|---------:|
|      -0.0562782| 0.0479613| 0.4493139|

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### Test that the exposure is upstream of the outcome


| snp_r2.exposure| snp_r2.outcome|correct_causal_direction | steiger_pval|
|---------------:|--------------:|:------------------------|------------:|
|       0.0004644|              0|TRUE                     |    0.0791316|

Note - R^2 values are approximate

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### Forest plot of single SNP MR

![plot of chunk chunk5](figure/Phosphatidylcholine_180203_levels_against_Malignantmelanomaofskinchunk5-1.png)

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### Comparison of results using different MR methods

![plot of chunk chunk6](figure/Phosphatidylcholine_180203_levels_against_Malignantmelanomaofskinchunk6-1.png)

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### Funnel plot

![plot of chunk chunk7](figure/Phosphatidylcholine_180203_levels_against_Malignantmelanomaofskinchunk7-1.png)

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### Leave-one-out sensitivity analysis

![plot of chunk chunk8](figure/Phosphatidylcholine_180203_levels_against_Malignantmelanomaofskinchunk8-1.png)
