Different Glabellar Contraction Patterns in Chinese and Efficacy of Botulinum Toxin Type A for Treating Glabellar Lines: A Pilot Study.

[BACKGROUND] Published research studies have described the existence of 5 glabellar contraction patterns. Botulinum toxin A (BoNTA) has been an approved and effective treatment of glabellar lines.

[OBJECTIVE] To study the pattern and frequency of glabellar contraction patterns in the Chinese population. To compare injection patterns and doses of BoNTA in Westerners within China.

[METHODS] Four hundred fifty-six healthy volunteers were randomly recruited. Photographs both in static and in frown state were taken and classified based on the method of 5 glabellar line patterns. The severity of the glabellar lines both at repose and during forced contraction was assessed by the Facial Wrinkle Scale (FWS). Subsequently, 75 of them were treated with BoNTA.

[RESULTS] The frequency of the various glabellar line patterns differs greatly between Chinese and Westerners with the "Converging arrows" pattern being the most common type and the "V" pattern being the least common when compared with the Westerners. Lower doses of BoNTA significantly improved the static and dynamic glabellar lines in the Chinese.

[CONCLUSION] The classification of 5 glabellar patterns is compatible for the Chinese population despite different proportions. The dosage of BoNTA should be less than 20 U during treatment in China with lowered incidence of complications.