Early menstruation may up stroke risk: study

Girls who start their periods early - at the age of 13 or younger - may be at a higher risk of stroke in later life, a new study has warned.
These women are also more at risk for cerebral infarction, in which a section of brain tissue dies due to reduced blood flow and oxygen.
Researchers at Tohoku University and Teikyo University in Japan also found that women who stopped menstruating at the age of 45 or younger are also more likely to get cerebral infarction, but not stroke, compared to women who began menopause at the age of 50.

Growing evidence suggests that the age women start and stop their periods, known as menarche and menopause respectively, factor into many diseases.
Understanding the connections - if there is a direct cause or if it can merely help in prediction - might allow public health professionals to develop more effective prevention measures.
To study the relationship between stroke and menstruation researchers followed a group of 1,412 postmenopausal women in the rural town of Ohasama, Japan, between 1998 and 2010.

Through initial questionnaires and follow-up surveys, they tracked the women's ages of menarche and menopause, if and when they had a stroke and other factors such as height, weight, heart disease and hypertension.

After taking confounding factors into account, researchers still found a statistically significant association between stroke risk and early menarche.
This finding supports another study that found the same trend among middle-aged women in the UK. Studies by other groups found no strong association, but the researchers point out that most of those studies focused on the relationship between menarche and stroke mortality, not just stroke risk.
"Early menarche might predict the incidence of stroke rather than the mortality caused by stroke," said Takayoshi Ohkubo, professor at Tohoku University.
Menstruation onset is influenced by genetic, behavioural and socioeconomic factors, among others.

Trying to delay menarche to help prevent stroke is a particularly interesting concept given that girls in developed nations are starting their periods earlier.
However, since the study only applied to a specific rural population, further research is required to conclude that delaying menarche would be an effective stroke prevention measure.
This study was published in the journal Neuroepidemiology.