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U.S. girls are starting their periods earlier and taking longer to reach regular menstrual cycles : Shots

Researchers say several factors are likely to impact early puberty, including obesity, stress and endocrine-disrupting hormones that are prevalent in the environment.

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In the United States, girls get their first period about 6 months earlier on average than in the 1950s and 1960s. And more girls are starting their periods before age 9, which is considered like a very early age. That’s according to a large new study published this week in the journal JAMA Open Network.

“It is important to educate caregivers, parents, and health care providers about this trend so we can prepare our children as well,” says Dr. Shruthi Mahalingaiah, study co-author and assistant professor of environmental health, Reproductive and Feminine at Harvard TH. Chan School of Public Health.

“The younger you are when you get your first period, it’s very confusing. There is still a lot of stigma and silence about it,” says Mahalingaiah.

The study is based on data collected from more than 71,000 women enrolled through the Apple Research app on their iPhones, who were asked to remember when they started having their period. Researchers found that, on average, menstruation started at age 11.9 between 2000 and 2005. That’s down from age 12.5 between 1950 and 1969.

Additionally, the percentage of girls who got their periods before age 11 increased from 8.6% to 15.5%, and those who started their periods before age 9 more than doubled.

The study found this trend toward earlier periods across all demographic groups, but it was much more pronounced among girls from racial and ethnic minorities and those from lower incomes.

Researchers say it’s important to understand changing menstruation trends because menstruation is a vital sign for health.

“The age at which a person starts menstruating is somewhat of a barometer of their overall health,” says Lauren Houghton, an assistant professor of epidemiology at Columbia University, who wrote a commentary accompanying the new study.

The study also found that more girls take longer to achieve regular menstrual cycles. Irregular menstrual cycles are associated with several health problems, including polycystic ovary syndrome, or PCOS. And an earlier age of menarche is linked to several adverse health outcomes, including a higher risk of cardiovascular risk, obesity, miscarriage and premature death. It is also linked to several cancers, including ovarian, endometrial, and breast cancer.

“If a person gets their first period before the age of 12, they have a 20% increased risk of developing breast cancer,” says Houghton.

When you look at populations, it becomes a very important public health problem, says Dr. Frank Biro, a clinician and researcher at Cincinnati Children’s Hospital Medical Center, whose work focuses on the factors that cause changes in puberty and associated health risks.

Biro cites other research that found that girls everywhere were developing breast buds — usually the first sign of puberty — six to 12 months earlier than before. Add to that the decline in the age of menarche, he says, “over the next ten or twenty years, we could expect an increase in new cases of breast cancer.”

Why does this happen?

So, what is behind the change in the timing of menstruation and puberty?

“When we look for causes or explanations, it’s not just one thing. It depends on several factors,” says Houghton.

For example, obesity is known to increase the risk of early puberty in girls, and rates of childhood obesity are increasing. But Houghton notes that stress is also a known factor and the two could be linked.

“When we’re more stressed, we get higher cortisol hormones, we get higher androgen hormones,” says Hougton. “And adipose tissue converts these hormones into estrogen. And it’s estrogen that signals the body to make breasts bigger.» Changes in estrogen levels also signal the body when menstruation begins.

Endocrine disruptors prevalent in the environment likely also play a role. For example, phthalates – a class of chemicals common in many cosmetic and personal care products – are known to interfere with hormones. Some air pollutants are also known to disrupt the endocrine system.

So what can concerned parents do?

Ensuring children eat a healthy diet – with plenty of fruits and vegetables – can help mitigate some risk factors for early puberty and menstruation, researchers say. Regular physical activity is also important. Getting enough sleep can also help – some studies have linked later bedtimes and shorter sleep duration to earlier puberty.

Mahalingaiah would also like to see parents prepare themselves and their children for the fact that menstruation might come sooner than expected, so that when the time comes, they are mentally ready.

This story was edited by Jane Greenhalgh

News Source : www.npr.org
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