Wikipedia:Reference desk/Archives/Science/2019 April 5

= April 5 =

The life expectancy of transgender people
How long do trans women and trans men live in comparison to cis women and cis men? As in, what is the average life expectancy of trans women and trans men (at least of those who are open about their transgender identity)? Futurist110 (talk) 06:19, 5 April 2019 (UTC)
 * There is not a lot of data on this issue, but this report from the Organization of American States says "In this regard, the IACHR has received information that the life expectancy of trans women in the Americas is between 30 and 35 years of age.", the IACHR being the Inter-American Commission on Human Rights, a commission within the OAS. It's not a lot, but it is a data point for you.  I can't find much on Google Scholar that has hard number:   Most of the scholarly papers that discuss it merely say "lower life expectancy" without giving data.  -- Jayron 32 12:50, 5 April 2019 (UTC)
 * Sorry, I cannot answer your question, but I would like to point out that there are a number of factors which will complicate your research. The first is that trans people are not a homogenous group in terms of how they express/enhance/suppress their gender. Some have top surgery, some have bottom surgery, some do neither; some take hormone blockers, some take hormones, some do neither; some wear unhealthy, restrictive clothing, some do not. Any of those choices will have an effect on life span, so any data would need to be contextualized to understand which factors have been applied. Also, I'm involved in the trans community and I've noticed that they have a higher probability of being part of other sub-groups which also have effects on life span. For example, several trans people I know are vegan. A large number of them also engage in self-harm, suicide ideation, and substance abuse. Depression and anxiety are also common. It also seems to be that many are also on the autism spectrum, but maybe that's just an idiosyncrasy of the local group. Matt Deres (talk) 13:13, 5 April 2019 (UTC)
 * Those are not "complications". Those are control factors. This type of research is performed all of the time. For example, I can compare a population of smokers to a population of non-smokers to calculate a difference in rates of lung cancer. I have to control for differences in age, race, gender, hypertension, diabetes, BMI, etc... That is normal in statistical research, not complicated. As a rule, there is more difference within each of two groups than differences between the two groups. 97.82.165.112 (talk) 22:08, 5 April 2019 (UTC)

I found this paper, which says that female-to-male trans procedures are "well tolerated". Though it has 'life expectancy' in the title, it doesn't specifically discuss the point. (I daydream of marrying Alexandra Elbakyan, and this paper like so many others is living my dream...) It says that two studies of 50 and 138 transmen found no extra incidence of heart disease (the main difference between mortality of the sexes) in people receiving testosterone. I take the implication from the wording that a difference in lifespan wasn't observed (there are some cancers described in remnant mammary tissue but I don't think it's as much as women would have). Wnt (talk) 11:05, 6 April 2019 (UTC)
 * What exactly was the point of the Elbakyan reference here? Futurist110 (talk) 06:57, 7 April 2019 (UTC)
 * Oh, just that without her selfless heroism, I wouldn't have been able to say as much about the paper. Wnt (talk) 12:41, 9 April 2019 (UTC)

Thank you very much for all of this information, you guys! Futurist110 (talk) 06:57, 7 April 2019 (UTC)

axial tilt and orbital inclination
If orbital inclination of Earth was taken as a reference, then its axial tilt cannot be necessarily considered as a real physical tilt caused by another event. I mean if axial tilt was taken as a 0 reference, shouldn't we consider Earth has orbital inclination of 23.5 degrees? Is there a way to distinguish which characteristic is more probable? For example, can solar rays and shadow distinguish this? Almuhammedi (talk) 19:41, 5 April 2019 (UTC)


 * Most astrophysicists don't really care which coordinate system you use; and engineers will use which-ever coordinate system is most appropriate for their needs: for example, people who work with Earth-orbiting satellites use Earth-centric coordinate systems; historical engineers working on Project Apollo might use an Earth-Moon-aligned coordinate system (and their modern counterparts almost surely use the LRO Standardized Lunar coordinates); and theoretical cosmologists might use barycentric coordinates; and so on.
 * So, parameters like orbital inclination and axial tilt are always defined with respect to some specified coordinate system. Relative to the Earth, for example, a comet or a hypothetical impactor or a NEO might have a different orbital inclination, even though its orbital inclination is definitionally zero in its own, self-referenced coordinate system.  It doesn't matter: we always conserve momentum, conserve energy, and use the methods of mathematical physics to correctly convert from one reference-frame to the other, subject to the extra difficulties of rotations and non-inertial relations, and in some of the more exotic astrophysical cases, a little extra work to ensure relativistic correctness.
 * A great textbook is Astronomical Algorithms, which includes an entire chapter on the transformation of coordinate-systems; and numerical constants are available from Jet Propulsion Laboratory.
 * Nimur (talk) 21:13, 5 April 2019 (UTC)
 * The reason inclination is usually not 23.4 is that the plane of the solar system and even the Moon orbit are not even close to Earth's equator and Earth's axis tilt relative to its orbit plane is what causes the seasons and some of the ice age glacials. Seasons are such a big deal that most calendars track them, the only major one I can think of now that doesn't care about seasons is Islamic . Sagittarian Milky Way (talk) 22:01, 5 April 2019 (UTC)
 * I agree about optional coordinate systems and that the solar system plane makes more sense with axilal tilting than inclination on average; however, I think seasons can still be the same if we switch between axial tilt and orbital inclination references. Almuhammedi (talk) 10:46, 6 April 2019 (UTC)
 * Well of course they are; a (non-quantum) physical phenomenon doesn't physically change just because you change the co-ordinate system you use to measure it. {The poster formerly known as 87.81.230.195} 90.200.138.194 (talk) 16:28, 7 April 2019 (UTC)