From April 2020 through September 2021, overall hospital visits for alcohol-related conditions spiked beyond what researchers expected, per a study published Friday in the journal JAMA Health Forum. Women ages 40–64, however, saw the largest monthly increases for all conditions, as well as alcohol-related liver disease (ALD) specifically.

Dr. Bryant Shuey, an assistant professor in the division of general internal medicine at the University of Pittsburgh School of Medicine, was lead author of the study. He’s also an internist who treats patients with alcohol use disorder (AUD), and tells Fortune he and his team set out to understand barriers to care for such patients.

“The research builds on the understanding that alcohol use and alcohol-related harms have increased over the last few decades, and that access to effective treatments hasn’t fully been realized,” Shuey says. “We were particularly interested in understanding, were there associations with not just increased alcohol use during the pandemic, but was that associated with alcohol-related harm that we could identify at the emergency department or hospital level.”

Using Optum’s Clinformatics Data Mart database, researchers analyzed the insurance claims data of more than 14.6 million people ages 15 and older, from March 2017 through September 2021. Nearly 30 diagnoses were included, from alcohol abuse with induced psychotic disorder to alcohol dependence with withdrawal delirium. From April 2020 onward, patients in emergency departments, inpatient units, and observation units were diagnosed in these categories:

• ALD: 57%–66%
• Alcohol withdrawal or alcohol-related mood disorder: 29%–37%
• Alcohol-related cardiomyopathy: 3%–4%
• Alcohol-related gastritis with bleeding: 1%–2%

In the overall study population, rates for such conditions increased nearly every month after the pandemic’s onset, but the increases were statistically significant for only four months and ranged from 8%–19%. Patients ages 40–64 showed nine months of statistically significant increases, of 17%–36%. Women in this age group had the most pronounced increases: 33%–56% across 10 months for all conditions, and 34%–95% across 16 months for ALD.

“Alcohol-related liver disease is a very serious condition. It occurs after years—often a decade or more—of persistent, excessive alcohol use,” Shuey explains. “But it can flare and it can worsen acutely, or over the course of weeks to months, with a sudden increase in alcohol use.”

Why is alcohol harm increasing among women?

Skyrocketing alcohol use during the pandemic may have exacerbated ALD among women who already had the condition, Shuey says. It’s just as possible the results of his study reflect newly diagnosed cases, too. Either way, he acknowledges his latest research likely underestimates the number of women with alcohol-related health conditions.

For starters, the stigma surrounding AUD may have led some patients not to disclose their drinking habits with hospital staff. Or a patient may have been billed under another code not included in the study. In addition, the database includes people who had continuous commercial health insurance or Medicare Advantage coverage for at least six months, leaving out people who were uninsured or underinsured.

“We just hope this study raises the alarm bells even more, and can provide more public health messaging that the gap between men and women in terms of alcohol-related harms is narrowing,” Shuey says.

Women had already begun dying of alcohol-related complications at a higher rate than men in the two decades preceding the pandemic, previous research shows. From 2016 to 2021, deaths from excessive drinking increased by 27% among males and 35% among females, according to the Centers for Disease Control and Prevention. But what are the underlying causes?

“Some people have theorized that this might have to do with normalization of alcohol use in general, as well as targeted marketing toward women with things like wine clubs, seltzers, fun-flavored beverages,” Shuey tells Fortune. “It’s also important to recognize that there’s disproportionate stress on women, who are oftentimes working full-time jobs, taking on a disproportionate share of family responsibilities.”

Even that is speculation, Shuey says: “We simply just don’t know what’s causing this.”

The team’s next step is to explore the pandemic’s effect on access to AUD treatment, namely medication and behavioral therapy. In 2022, less than 10% of adults with the disorder had received any treatment in the last year, according to the National Survey on Drug Use and Health.

If you or a loved one are struggling with alcohol use, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) Alcohol Treatment Navigator can connect you to self-guided programs, telehealth treatment, mutual support groups, and health care professionals who are trained to help. If you need immediate support, contact the 988 Suicide & Crisis Lifeline.

For more on how alcohol impacts your health:

• Just one alcoholic drink a day can increase your risk of cancer. But most Americans don’t know the dangers, new survey says
• Binge drinking is on the rise among older adults. Here’s why it’s more dangerous and how to spot the signs
• More Americans than ever—especially young adults—say drinking alcohol is unhealthy
• Alcohol and drug use linked to over 3 million annual deaths worldwide
• Is moderate drinking good for your health? Science says no