Various factors can affect a woman’s risk for breast cancer. Some of these factors, including whether or not a woman is physically active, are within her control. But others are not, and those include when she started to menstruate.

According to Breastcancer.org, women who started menstruating prior to age 12 have a higher risk of developing breast cancer later in life. But that’s not the only link between menstruation and breast cancer risk, as women who go through menopause when they’re older than 55 years of age also have a higher risk of developing breast cancer later in life.

Breastcancer.org notes that, over the last two decades, girls have begun puberty at younger ages than girls in previous generations. Researchers have linked that phenomenon to the obesity epidemic and broad exposure to hormone disruptors. A rise in hormones triggers the onset of puberty. The breast tissue of girls who begin menstruating at a younger age tends to be immature and sensitive to hormonal influences, which is associated with a higher risk of breast cancer later in life.

Women may not be able to control when they start and stop menstruating, but they can control certain factors that can make them less likely to menstruate early. Breastcancer.org notes that maintaining a healthy weight, exercising regularly and eating nutritious foods are some lifestyle choices that girls and women can make to keep their risk for breast cancer as low as possible.

Various factors can increase a woman’s risk of developing breast cancer. Understanding the link between those factors and cancer risk can help women make healthy decisions that benefit both their short- and long-term health.