Prevalence of androgenetic alopecia in China: a community-based study in six cities.

Background: There are racial differences in the prevalence and types of androgenetic alopecia (AGA). The prevalence of AGA has been studied in Caucasians and in some Asian people. In China, although there have been some epidemiological studies carried out in single cities or regions, no multicentre population-based study has been reported.
Objectives: To study the prevalence and types of AGA in China and to compare the results with those previously reported in Caucasians and in other Asian people.
Methods: A community-based study was carried out in six cities of China. Subjects were interviewed face-to-face and completed questionnaires. The degree of AGA was classified according to the Norwood and Ludwig classifications.
Results: In total 17 886 subjects were interviewed and 15 257 completed the questionnaires. In men, the overall prevalence of AGA was 21.3%, with 2.8% in men aged 18-29 years, 13.3% in those aged 30-39 years, 21.4% in those aged 40-49 years, 31.9% in those aged 50-59 years, 36.2% in those aged 60-69 years and 41.4% in those aged 70 years and over. The most common type was frontal and vertex hair loss. A small number of subjects (3.7%) showed 'female pattern' hair loss. In women, the prevalence of AGA was 6.0%, with 1.3% in women aged 18-29 years, 2.3% in those aged 30-39 years, 5.4% in those aged 40-49 years, 7.5% in those aged 50-59 years, 10.3% in those aged 60-69 years and 11.8% in those aged 70 years and over. Ludwig grade I was the most common type. The prevalence of AGA varied between cities. A positive family history was present in 29.7% of men and 19.2% of women with AGA.
Conclusions: The prevalence of AGA in Chinese men and women was lower than in Caucasians and similar to that in Koreans.