Vasomotor symptom prevalence and language of menopause in Japan

To characterize the prevalence of vasomotor symptoms affecting menopausal women in Japan, the relationship between vasomotor symptoms and menopause status as defined by menstrual patterns versus self-assigned kōnenki (climacteric) status, and the salience and specificity of hot flash terminology.

Participants were healthy Japanese women, aged 45 to 55 years, living in Kyoto and Fukushima prefectures, divided into menopause groups based on menstrual patterns and self-assigned kōnenki groups. Women recalled 82 general health symptoms during the previous 2 weeks, and provided detailed descriptions of hot flash symptom terms.

Hot flash prevalence ranged from 3.0% (hotto furasshu) to 17.1% (hoteri) depending on the individual term used, and was 22.1% when all hot flash terms were combined. Prevalence of vasomotor symptoms was 25.7%, but peaked at 52.6% among late perimenopausal women. Hot flash prevalence was 13.2% among premenopausal women, but zero among self-assigned pre-kōnenki women. The three major hot flash terms (kaa, nobose, and hoteri) vary in their physical location, characteristics, and cultural salience.

Vasomotor symptom prevalence rates in Japan have increased over the past 20 years but are still lower than in most Western populations, and vary according to hot flash term, and between menopause and self-assigned kōnenki status. Kōnenki status appears to be a better predictor of hot flashes than menopause status. Japanese women's language, including self-assessed kōnenki stage and hot flash terminology, seems to be more fine-grained than Western biomedical terms of menopause status and hot flash, and may offer insight into subtle differences in experiences and underlying physiology of menopause.