This month our study results were published in a special edition of Clinical Chemistry describing how laboratory values in transgender men and women when taking hormone therapy. While retrospective, we hope that this information will help improve transgender medicine.
There were many interesting results found in the study and I hope to describe bits of them in greater detail each month.
We wondered what we might find if we took a broad, unbiased approach comparing all laboratory parameters commonly measured by physicians. Just because there are no sex-specific differences in analytes, changes could still occur secondary to exogenous hormone use.
Albumin, which is the principle protein in our blood, was found to be decreased in transgender women after taking at least 6 months of estradiol therapy (p<0.0001)1. This was unexpected, because one reference range for albumin is used for cisgender males and females.
Frequently, changes in lab values move in opposite directions for transgender patients taking estradiol vs. testosterone (ex. hemoglobin goes up with testosterone and down with estradiol). We wondered if a similar opposite change might occur in albumin for transgender men taking testosterone. However, there was no change in albumin levels from baseline for transgender men.
The cause of decreased albumin was not readily available, but several factors could be influential. Albumin levels reflect the long term nutritional status of a patient as it has a long half life for turnover (t½= 3-4 weeks). Thus, the change in albumin could reflect a dietary change in transgender women. However, in the chart review there was nothing to suggest a substantial change in diet. While several of the patients would go on diets and lose weight, the weight loss was (unfortunately) often short lived (< 1 year). Looking towards a more objective reflection of dietary changes, the body mass index was nearly the same for transgender women pre-hormone therapy vs. while on hormone therapy (BMI: 27 vs 29, p>0.05).
Some studies have shown an increased prevalence of disordered eating behaviors among transgender individuals2, which could affect overall nutritional status as reflected in albumin. However, this should be controlled for by the control group, which is just transgender patients who haven’t taken hormones previously.
Another consideration is that body composition changes in transgender patients such that transgender women lose lean mass and have an increase in body fat percent3. Although this could affect the metabolic profile (which it didn’t in our study), changes in fat percent don’t explain altered albumin levels.
Albumin levels are also low in patients with chronic liver disease, but this would be inconsistent with the patients’ medical history or other lab results. Frank nephrotic syndrome is unlikely as there were no reports of this disease within our population, but we did not have data on urinalysis, so we can’t say for certain.
One study did show that males (TW baseline equivalent) have higher albumin than females at younger ages (<60 y.o.) that equilibrates in later decades4. This sex-specific difference shows how estradiol decreases albumin to cisgender female levels. However, the reverse effect (increased albumin) does not occur with testosterone in transgender males. This demonstrates how sex-specific reference intervals cannot be simply reversed for transgender patients.
In a normal set of outpatients in the UK, oral contraception use (which includes estradiol) in women decreased their albumin levels by 0.2 g/dL, which is a smaller magnitude than found in our study, but supports a hormonal basis for sex-specific differences in albumin4.
Although the decrease in albumin for our cohort was not clinically significant (did not pass lower limit of normal albumin reference interval), it would be important to monitor albumin levels in older or elderly transgender females on hormone therapy. Elderly patients are at increased risk of hypoalbuminemia, especially when hospitalized5.
Summary:
- Albumin is decreased in transgender women taking estradiol therapy.
- Albumin levels do not fall below normal ranges.
- This could be more important in older or elderly transgender patients who are already at risk of hypoalbuminemia.
References
- SoRelle JA, Jiao R, Gao E et al. Impact of Hormone Therapy on Laboratory Values in Transgender Patients. Clin Chem. 2019; 65(1): 170-179.
- Diemer EW, Grant JD, Munn-Chernoff MA et al. Gender Identity, Sexual Orientation, and Eating-Related Pathology in a National Sample of College Students. J Adolesc Health. 2015; 57(2):144-9.
- Auer MK, Cecil A, Roepke Y et al. 12-months metabolic changes among gender dysphoric individuals under cross-sex hormone treatment: a targeted metabolomics study. Sci Rep. 2016; 6: 37005.
- Weaving G, Batstone GF, Jones RG. Age and sex variation in serum albumin concentration: an observational study. Annals of Clinical Biochemistry 2016, Vol. 53(1) 106–111.
- Cabrerizo S, Cuadras D, Gomez-Busto F et al. Serum albumin and health in older people: Review and meta analysis. Maturitas. 2015; 81(1):17-27.
-Jeff SoRelle, MD is a Molecular Genetic Pathology fellow at the University of Texas Southwestern Medical Center in Dallas, TX. His clinical research interests include understanding how the lab intersects with transgender healthcare and advancing quality in molecular diagnostics.
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