Sheath size, radial occlusion, and ethnicity: Real or confounded?

Japanese participants experienced higher incidence of radial artery occlusion when compared to non-Japanese participants. The use of 6Fr Slender sheath was inferior for radial artery occlusion than 5Fr sheath in Japanese, but no different in non-Japanese participants. Is not clear if this apparent ethnical interaction is real versus confounded, warranting more research in the area.