tl;dr There are no reliable figures for suicide in this group. Overall, and I searched very thoroughly, we're nowhere near robust statistics.
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Earlier studies are hampered by the very different dosages of hormone therapy that are known to have a substantial impact on mood/mental health etc. The surgical techniques then had different consequences. And this is why figures can vary across time periods.
We need longitudinal studies to assess suicide risk but they will always be slightly ??? because of advances in medical technology and (even) social attitudes over time.
And, people can withdraw their consent to have their data included - researchers have altered the ways in which they account for this over time and this can (inadvertently) cause very complex contexts for interpreting data.
And, data can disappear partway through because the people involved may need to halt transition for medical reasons (e.g., the hormones are causing serious health complications).
Overall, and I searched very thoroughly, we're nowhere near robust statistics.