Review on April 30, 2009
Margaret Lock of McGill University (Canada), reports that Japanese women are less likely than North American women to suffer night sweats during menopause. In her "Psychosomatic Medicine," she reports the reason for fewer night sweats among Japanese women as a mix of biological and cultural factors. She also notes that diet, lifestyle factors, and evolutionary differences might play a part in determining night sweats.
Dr Lock's results come after a decade of studying Japanese and American women. She collected statistics from 1,200 Japanese women and 2,100 North American women in accordance with night sweats. Though more research is needed, she believes estrogen levels are only part of the problem of night sweats among menopausal women.
Other studies done by SWAN in Pittsburgh show a more specific breakdown in ethnicity. During perimenopause, night sweats are more common in African American women (46% ) and Hispanics and Caucasians (30%) than Japanese women (20%).
Another study undertaken in Hawaii proves that Japanese-American women living in Hawaii also experienced fewer night sweats than European-American women living in the same state. This tends to favor that biological factors cause night sweats perhaps more than location or culture. Japanese-American women reported a higher intake of soy, but soy intake was not associated with fewer vasomotor symptoms.
More research is needed to determine exactly why Japanese women experience fewer night sweats than European-Americans but evidence points most strongly to biological factors, and then to diet and culture.