Women who start menstruating early may be at increased risk of asthma and poor lung function, new research shows.
Having one's first period at age 10 or earlier nearly doubled asthma risk, Dr. Ferenc Macsali of the University of Bergen in Norway and his colleagues found.
"One might want to be alert regarding the potential increased asthma risk in girls with early menarche; programs focusing on ... smoking prevention in adolescents might include early menarche as an indicator of increased risk for impaired respiratory health," they conclude in the American Journal of Respiratory and Critical Care Medicine.
Women in the developed world are menstruating earlier, Macsali and his team note, with the average age at menarche-the medical term for a girl's first period-now occurring before age 13, on average, compared with 16 to 17 a century ago.
Early menarche has been tied to a number of health risks, they add, including heart disease and breast cancer.
Because hormones appear to play a role in asthma and lung function (for example, asthma risk is higher in boys than girls before puberty, but the reverse is true after puberty), the researchers investigated whether the age when a woman began menstruating had any association with her asthma risk and respiratory function in adulthood. They looked at 3,354 women 27 to 57 years old participating in a Europe-wide study of respiratory health.
Results of two key tests of lung function-forced expiratory volume in one second, meaning the amount a person can exhale after a deep breath in a second, and forced vital capacity, the total volume of air one can exhale after a deep breath, were worse for women who started menstruating at age 10 or earlier compared to women who had their first period at 13, the researchers found.
The women whose periods started early were also nearly three times as likely to report having at least three symptoms of asthma (such as wheezing, shortness of breath, and being woken up by a cough) along with bronchial hyperresponsiveness-an exaggerated response to inhaling substances that cause the airways to constrict, which is a key symptom of asthma.
There are several factors that could be involved in the menarche-lung function relationship, Macsali and his colleagues say. For example, girls who menstruate earlier tend to be shorter, while taller people tend to have better lung function.
That relationship between body size and lung function may originate with events during fetal development that could also influence later growth and onset of puberty, they add.
Overweight and obesity also have been linked to earlier puberty, and may promote inflammation, a key factor in asthma.
Based on their findings, the researchers conclude that hormonal and metabolic factors may indeed be involved in women's respiratory health.