Means or frequencies for sociodemographics and background covariates are presented in Table 1. Frequencies for intervenable variables and past-year suicide ideation and attempt are presented in Table 2. In the past year, 35.1 % (95 % CI: 27.6, 42.5) had seriously considered suicide, and 11.2 % (95 % CI: 6.0, 16.4) reported that they had attempted it.
Findings on model-standardized risks are presented in Table 3 for suicide ideation and in Table 4 for suicide attempts (among those with ideation), along with model-standardized relative risks and population attributable risks. Average relative effects on individuals, and at a trans population level, were sometimes strong. High levels of social support (90th percentile) versus low levels (10th percentile) were significantly associated with a 49 % reduction in suicide ideation (RR = 0.51; 95 % CI: 0.28, 0.94), and with a further 82 % reduction in attempt risk among those with ideation (RR = 0.18; 95 % CI: 0.04, 0.73). This would be associated with potential prevention of 100 cases of ideation per 1,000 trans persons (cPAR = 0.10), and a further prevention of 220 attempts per 1,000 trans persons considering suicide (cPAR = 0.22). Among sources of strong support for gender, only support from parents was statistically significantly associated with reduced risk, with RR = 0.43 (95 % CI: 0.26, 0.73) for past-year ideation, and no additional statistically significant effect on the risk of attempts among those with ideation. At a population level, this corresponds to potential prevention of 170 trans persons per 1,000 (cPAR = 0.17) from seriously considering suicide (and thus also reducing the risk of attempt through lowering the proportion at risk). Interestingly, strong support from leaders such as supervisors or teachers was significantly associated with an increased risk of attempts among those with ideation (RR = 5.24; 95 % CI: 2.20, 12.46). Having one or more identity documents concordant with lived gender was significantly associated with reductions in past-year ideation (RR = 0.56; 95 % CI: 0.35, 0.90) and attempts (RR = 0.26, 95 % CI: 0.11, 0.62), with the potential to prevent 90 cases of ideation per 1,000 trans persons (cPAR = 0.09), and 230 attempts per 1,000 with ideation (cPAR = 0.23). Religiosity was not associated with suicidality.
Both transphobia variables in the analysis were associated with ideation and attempts, with lower transphobia associated with reduced risk. Lower overall transphobia (10th percentile vs. 90th) was statistically significantly associated with a 66 % relative risk reduction of past-year ideation (RR = 0.34; 95 % CI: 0.17, 0.67) and an additional 76 % relative risk reduction (RR = 0.24; 95 % CI: 0.07, 0.82) for attempts. This represents a potential prevention of 160 cases of ideation per 1,000 trans persons (cPAR = 0.16), and potential prevention of 200 attempts per 1,000 with ideation (cPAR = 0.20).
Medical transition variables, but not social transition or being perceived as cisgender, were associated with suicidality. Among those who desired medical transition, those on hormone therapy were about half as likely to have seriously considered suicide (RR = 0.52; 95 % CI: 0.37, 0.75). The process of medically transitioning overall was more complex, with a monotonic reduction in suicide ideation from planning to transition vs. being in process, vs. completing. However, among the sub-group with ideation, being in the process of transitioning was significantly associated with increased risk of an attempt (RR = 2.91; 95 % CI: 1.48, 5.76) in comparison with those who were planning to transition but had not yet begun. We did not observe an increased risk in this sub-group among those who completed a medical transition (RR = 0.51; 0.07, 3.74). Completing a medical transition had beneficial individual and population effects. It was associated with a 62 % relative risk reduction (RR = 0.38; 95 % CI: 0.22, 0.66) in ideation. On a trans population level, to facilitate completion of medical transition (when desired) would correspond to preventing 170 cases of ideation per year per 1,000 trans persons (cPAR = 0.17), representing 44 % of ideation (c%PAR = 0.44), and further preventing 240 attempts per 1,000 with ideation (cPAR = 0.24) or 69 % of attempts in this group (c%PAR = 0.69).
BMC Public Health. 2015;15(525) © 2015 BioMed Central, Ltd.