Early bloomers and Type 2 Diabetes

When you had your first period provides clues about your future health

When I see patients in the office, the questions I ask have a very clear purpose. At least it’s clear to me. But what I am trying to get out of a particular question may not be so obvious to my patients. When they look confused or surprised, I try to give them a peek at my thought process.

One question that catches lots of people off guard is how old they were when they had their first period. Some are flummoxed, stumbling to recall. Many give a non-committal answer like “around the usual time.” Others have vivid memories of summer camp or middle school bathrooms. They all want to know why it matters now that they are in their 40s or 50s.

Why the timing of your first period matters

A new study published in the Journal of Clinical Endocrinology and Metabolism makes that question easier to answer than ever before. One reason I ask about a patient’s very first period is because previous studies have shown that getting your first period early (before the age of 10 or so) is associated with an increased risk of developing Type 2 diabetes later in life.

If you are a long-time reader, you know that association is not the same as causation. Just because an early first period is associated with getting Type 2 diabetes later, does not mean that early onset menstruation causes diabetes. In fact, researchers are still trying to find the specific connection between these two seemingly unconnected events.

Clues about the connection between first periods and diabetes

When it comes to understanding biological cause and effect, some of our most reliable types of studies aren’t possible. I cannot randomize a group of girls to get their first period at different ages and then follow them for 40 to 50 years to see if they get diabetes. Instead, researchers will often turn to large registry studies to look for clues. This new study does just that. The authors used data from the National Health and Nutrition Examination Survey (NHANES) a database full of information about thousands of participants collected continuously since 1999.

The authors pulled information from more than 20,000 women collected between 1999 and 2018. Using that information, they were able to show that women who started their period before age 10 often had elevated markers of inflammation and early signs of disrupted glucose metabolism in midlife even though they didn’t have diabetes.

The authors suggest that earlier exposure to sex hormones may kick off this cascade. I am not convinced by their argument. Let me explain. We know that for nearly 200 years the first menstrual period (also called menarche) has been gradually transitioning to earlier onset. We don’t know exactly why that is happening, but experts have some theories.

Many of those theories center around nutrition. Early changes in the timing of menarche coincides with the increased availability of food—in developed countries famine is largely a thing of the past—and then the availability of too much food, especially food that is high in calories and low in nutritional value (think Doritos). The advent of processed foods designed to get people to eat more of them, not only coincides with shifts in the timing of puberty, but also with more and more people developing Type 2 diabetes.

We also know that women with a family history of type 2 diabetes are more likely to experience early menarche. That spurs me to ask the question, is there something that is causing both early menarche and inflammation that is leading to problems with glucose metabolism and Type 2 diabetes? If so, could we intervene and prevent both early menarche (no kid under 10 needs to be dealing with menstrual periods) and reduce women’s risk for diabetes? We’ll have to wait and see.

How this study informs my practice

The fact that we don’t yet have things all figured out isn’t stopping me from using this information in my practice now. I have screened women who had early menarche for Type 2 diabetes for a long time. But this study provides some evidence for screening for early signs of inflammation and disordered glucose metabolism before women get Type 2 diabetes. Now that more and more girls are experiencing early menarche, recognizing which women are at especially high risk of developing diabetes will be more important than ever.

Once we know someone is heading down the path toward Type 2 diabetes, there are evidence-based interventions we can implement to prevent that progression. For example, starting medications like metformin and GLP-1 receptor agonists has been shown to prevent Type 2 diabetes in people at high risk.

Ultimately, we are just beginning to understand the links between the timing of a girl’s first menstrual period and the health risks associated with that. But every new discovery helps us keep women healthy as they age.

The Savvy Short:

· Women who had their first menstrual period before age 10 are at increased risk of developing Type 2 diabetes later in life.

· A new study suggests that even before women develop diabetes, their blood shows signs of inflammation and early changes in glucose metabolism.

· It may be that increased exposure to hormones causes this inflammation, or it may be that there is something that cause both early menarche and increased inflammation.

· Knowing which women are at highest risk for Type 2 diabetes allows us to treat them proactively, potentially preventing diabetes from developing.