Menopause in Australia and Japan: effects of country of residence on menopausal status and menopausal symptoms.

OBJECTIVES: The aim of the study was to explore the effects of country of residence on menopausal status and menopausal symptoms in Australian and Japanese women. The study objectives included exploring the impact of country of residence (Australia and Japan) and menopausal status on menopausal symptoms, and identifying whether country of residence (Australia and Japan) moderates the relationship between menopausal status and menopausal symptoms. METHODS: Analyses are based on 1743 women aged between 40 and 60 years who participated in the multi-race, multi-site, cross-sectional study of mid-aged women called the Australian and Japanese Midlife Women's Health Study (AJMWHS) in 2001--2002. Study participants completed a mailed questionnaire that contained questions on a variety of health-related topics. RESULTS: In both cultures there was a similar increase in prevalence of depression (p < 0.001), somatic symptoms (p < 0.001) and vasomotor symptoms (p < 0.001) at perimenopause. Australian women experienced more night sweats than Japanese women but the prevalence of hot flashes was not statistically different. Postmenopausal Japanese women had more somatic, psychological and sexual symptoms. The main effect for menopausal status and the interaction effect of country of residence was significant in the somatic symptoms (p < 0.001), but not in any of the other areas. CONCLUSIONS: Vasomotor, psychological and somatic symptoms decrease after menopause in Australian women, with only sexual symptoms continuing. In Japanese women, somatic, psychological and sexual symptoms remain high after menopause. It is possible that westernization may be having a significant impact on the aging of women in Japan and it is, therefore important to capture through research just what this impact may be.

Impairment of autonomic function induced by posture change in postmenopausal women.

This study was designed to determine if there is a difference in autonomic regulation induced by posture change between postmenopausal and young women. To evaluate autonomic nervous system function, spectral analysis of heart rate variability (HRV) was done in postmenopausal women (n = 13, 46-59 years of age), age-matched men (n = 8, 45-55 years of age), and young women (n = 10, 20-37 years of age) for 3-min periods of controlled frequency breathing (15 breaths/min) in supine followed by sitting positions. In the supine position, the R-R interval variation in older persons decreased significantly compared with that during the follicular phase in young women. Furthermore, the high-frequency (HF) components of HRV, which reflect only parasympathetic activity, were lower in older subjects than in young women. Following a change of position from supine to sitting, the HF component did not change significantly in the postmenopausal women or the men, but the low/high frequency (LF/HF) component ratio, which reflects the balance of autonomic nerve activities, increased significantly in the men. These results suggest that cardiac parasympathetic tone may be reduced in older persons in comparison with young women. Furthermore, arterial baroreflex control of parasympathetic nerve activity caused by posture changes is impaired in the postmenopausal women and aged-matched men. The baroreflex control of the sympathetic component is maintained in the men but not in the postmenopausal women. These differences might result in part from changes in the level of female hormones.

Reflex control of autonomic function induced by posture change during the menstrual cycle.

This study was designed to determine whether autonomic regulation induced by posture changes varies during the menstrual cycle. Heart rate variability (HRV) was analyzed in women with normal menstrual cycles (n = 10, age range 20-37 years) during 3 min periods of controlled frequency breathing (15 breaths/min) in supine followed by sitting positions. In a supine or sitting position, high frequency (HF) components of HRV, which reflects only parasympathetic activity, were significantly high in the follicular phase compared with those in the menstrual phase, suggesting that parasympathetic nerve activity increases in this phase. Following the change of position to sitting from supine, the HF component decreased significantly in the menstrual, ovulatory and luteal phases, but not the follicular or premenstrual phase. After changing the position to sitting, the low to high frequency component ratio, which reflects the balance of autonomic nerve activities, was increased significantly in the menstrual, luteal and premenstrual phases, indicating that sympathetic nerve activities in these phases became predominant by the sitting position. These results suggest that parasympathetic nerve activity is predominant in the follicular phase, resulting in an impairment of baroreflex caused by posture changes. Moreover, baroreflex control of the sympathetic component, not the parasympathetic component, increases in the premenstrual phase, while the reflex response of the sympathetic component is less in the ovulatory phase compared with the menstrual or luteal phase. We concluded that baroreflex regulation of autonomic functions induced by changing positions is modified during the menstrual cycle. A difference of a balance of ovarian hormones may be responsible for these changes of autonomic functions during the menstrual cycle.