Various factors influence the age at which a girl will begin to have menstrual periods. Many of these factors are genetic but some of them can be controlled by personal choice. New research indicates too many sugary sweet beverages can hasten the onset of menstruation and increase the risk of breast cancer.
Most girls get their first period between the ages of 9 and 15, often about the same age as their mother started menstruating, but other factors are influential, too. Some unmodifiable factors that influence the age of menarche include:
- Birth weight
- Race or ethnicity
- Height
- Family composition
Lifestyle influences include:
- Physical activity level
- How often dinner is eaten together as a family
Body mass index (BMI) has been linked to early menarche in previous studies. The average weight of Americans at every age has increased in the past 40 years. As young girls’ average body weight has increased, the average age of onset of puberty and the beginning of menstruation decreased.
Sugar-sweetened beverages (SSBs) are frequently implicated as the main driver of the growing obesity epidemic in young children and teenagers. Karin Michaels, an associate professor at Harvard Medical School in Boston, wanted to know how big an influence these SSBs truly are. She and her colleagues followed 5,583 girls for five years to learn about their consumption of SSBs and the onset of their menstrual cycles. Each girl had a parent participating in the Nurses’ Health Study II, was between 9 and 14 at the beginning of the study, and none had reached menarche when the study began in 1996. From 1996 to 1998, each girl was periodically queried about her dietary habits and if she had started menstruating. The girls were followed until 2001. All 50 states were represented in the study.
Of particular note was the type and frequency of beverages the girls drank:
- One can or glass of sugar-sweetened carbonated soda or diet soda
- One glass of non-carbonated fruit drinks such as lemonade or punch
- One glass, can, or bottle of sweetened iced tea
The SSBs were sweetened with any form of sugar (corn syrup, glucose, sucrose, etc.). The colas and teas were noted for their caffeine content.
Girls who routinely drank 1.5 servings or more a day of the SSBs reported their first period started an average of 2.7 months before the girls who drank fewer than two SSBs a week. The average age of menarche was:
- 12.8 years for those drinking 1.5 servings or more of SSBs every day
- 13 for those drinking the least
When all other factors were included in Michaels’ analysis, including BMI, the results remained the same. Even girls with high BMIs and other influential factors making them more prone to early menarche did not experience early menarche when they consumed fewer than two SSBs per week.
Early onset of menarche is a risk factor for breast cancer development in adulthood.
Sources:
- Michaels, Karin B., et al "Sugar-sweetened beverage consumption and age at menarche in a prospective study of US girls." Human Reproduction. Oxford University Press / European Society of Human Reproduction and Embryology, 27 Jan. 2015. Oxford Journals. Web. 24 Feb. 2015.
- Muir, Tristi. "Young girls’ change starts with menarche." UTMB Health / Working Wonders. University of Texas Medical Branch, 14 May 2014. Web. 24 Feb. 2015.