The PCOS Phenotype in Unselected Populations study: ethnic variation in population-based normative cut-offs for defining hirsutism.

Summary

In 9,829 community participants across eight countries, ethnicity-specific normative cut-offs for hirsutism (mFG scores) ranged from 4 to 8, confirming 2023 PCOS guideline recommendations while highlighting meaningful ethnic variation. These data justify ethnicity-tailored thresholds to reduce misclassification in PCOS evaluation.

Key Findings

• Ethnicity-specific mFG normative cut-offs ranged from 4 to 8 across 9,829 participants.
• Highest cut-off: White Iranians (8); elevated cut-offs in White Italians and Black Africans (7).
• Cut-offs of 5 for Han Chinese, White Russians, Turkish, and Black Americans; 4 for White Americans, Asian Koreans, Asian/Mixed Russians.
• Findings confirm 2023 International PCOS Guidelines and emphasize the need to consider ethnicity.

Clinical Implications

Adopt ethnicity-specific mFG cut-offs (range 4–8) when defining hirsutism to improve diagnostic accuracy for PCOS and tailor management. Aligns with, and refines, international guideline recommendations.

Limitations

• Cross-sectional design limits causal inference for determinants of hirsutism
• Potential heterogeneity in mFG assessment and ethnic classification across studies

Future Directions

Prospective validation of ethnicity-specific thresholds against clinical outcomes and androgen levels; integration with AI-assisted image scoring to reduce inter-rater variability.