Systematic Review and Meta-analysis of Facial Anthropometric Variations Among Cisgender Females of Different Ethnicities: Implications for Feminizing Facial Gender Affirming Surgery

Abstract

Background: Feminizing Facial Gender-Affirming Surgery (FFGAS) is gaining popularity among the diverse population of patients impacted by gender incongruence. However, most studies examining facial femininity are based on Caucasians. Thus, it is unclear if ethnic differences exist in anthropometric measures relevant to FFGAS procedures. This study aims to analyze ethnic anthropometric variations in the cisgender female face to identify differences that are potentially relevant to FFGAS. Methods: A systematic review and meta-analysis of the PubMed, EMBASE, and Cochrane databases was performed following PRISMA guidelines on June 25, 2021. Original studies reporting facial anthropometry in cisgender women were included. Anthropometric measures of interest included mandibular and zygomatic width, facial and forehead height, and nasolabial angle. A meta-analysis was performed using a linear mixed-effects model for each anthropometric measure. Results: A total of 1246 abstracts were screened, yielding 21 articles that met the inclusion criteria. Facial anthropometric data of 4792 cisgender females of 16 different ethnicities were analyzed. This meta-analysis demonstrated that compared with Caucasian cisgender women, Japanese, Chinese, and Korean cisgender women had a wider mandible (Japanese +20.13 mm [SE 4.43, P<0.001, P value adjusted for multiple comparisons (p-adj)=0.002], Chinese +16.22 mm [SE 4.39, P=0.002, p-adj=0.013]; and Korean +14.46 mm [SE 3.97, P=0.002, p-adj=0.014]). Further, when compared with Caucasian cisgender women, Chinese cisgender women demonstrated a larger zygomatic width, African American cisgender women tended to have smaller nasolabial angles, and Indian and Japanese cisgender women tended to have a smaller and larger facial height, respectively. However, following P value adjustment for multiple comparisons, these differences were not found to be statistically significant. Conclusions: We found that mandibular width tends to be greater for Japanese and Chinese cisgender women relative to Caucasian cisgender women. This data may be useful in counseling patients during preoperative evaluations ahead of mandibular reduction. No other anthropometric features were found to be significantly different among the ethnic groups studied. This portends that current approaches to FFGAS, which emphasize patient-specific needs and maintenance of a harmonious appearance, may require minimal or no adjustment to account for ethnic facial anthropometric differences.