Health Rounds: Genetics play a role in higher depression risk for women

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(This is an excerpt of the Health Rounds newsletter, where we present latest medical studies on Tuesdays and Thursdays.)

By Nancy Lapid

(Reuters) -Genetic factors contribute more to depression risk in females than in males, according to a large Australian study that may help further understanding of why women are more likely to suffer from the condition.

Analyzing DNA samples from nearly half a million people, researchers found roughly twice as many genetic ‘flags’ for depression in females compared with males, the research team reported in Nature Communications.

“We already know that females are twice as likely to suffer from depression in their lifetime than males,” study leader Dr. Brittany Mitchell of QIMR Berghofer Medical Research Institute in Brisbane said in a statement.

“Until now, there hasn’t been much consistent research to explain why depression affects females and males differently, including the possible role of genetics,” Mitchell said.

The team identified about 7,000 changes in DNA that could cause depression in both sexes, and about a further 6,000 DNA changes that could cause depression in females only.

The researchers also found that the genetic factors linked to depression overlap more with genes for metabolic traits in females than in males.

The differences may help explain why females with depression more often experience metabolic symptoms such as weight changes or altered energy levels, they said.

The researchers say most drug trials and therapies are tested on males, and they hope their work will also translate to a greater clinical understanding of female depression.

“These findings underscore the importance of considering sex-specific genetic (factors) in the study of health conditions, including major depressive disorder, paving the way for more targeted treatment strategies,” the researchers concluded.

MICROPLASTICS ALTER HEALTHY GUT BACTERIA POPULATIONS

Tiny pieces of plastic that find their way into human intestines can adversely impact the healthy bacteria and other microbes that naturally live there, known as the gut microbiome, laboratory experiments suggest.

Some of the microplastic-induced changes in gut microbes observed in test tubes were similar to changes seen with depression, colorectal cancer, and other diseases, researchers reported at the ongoing United European Gastroenterology (UEG) Week meeting in Berlin.

Earlier studies have found microplastics in stool samples and colon biopsies in a significant proportion of volunteers.

The new study used stool samples from five healthy volunteers to grow gut microbiome cultures in the lab. The cultures were then exposed to five common types of microplastic particles at concentrations reflecting estimated human exposure.

For the most part, total bacterial counts did not change. However, the microplastic-treated cultures showed significant drops in pH levels, indicating altered microbial metabolic activity, researchers found.

They also saw microplastic-specific shifts in bacterial composition, with certain bacterial groups increasing or decreasing depending on the microplastic type.

Shifts in bacterial composition were accompanied by changes in bacterial production of chemicals that nourish intestinal cells, aid in digestion of food and processing of medications, and influence mood and brain function.

The researchers don’t yet know how microplastics induce these effects. And their study did not look at long-term effects of microplastics exposures on gut bacteria, nor did it consider the effects of additional factors like diet and immune response.

“The key takeaway is that microplastics do have an impact on our microbiome,” study leader Christian Pacher-Deutsch of the Medical University of Graz, Austria said in a statement.

“While it’s too early to make definitive health claims, the microbiome plays a central role in many aspects of well-being, from digestion to mental health. Reducing microplastic exposure where possible is therefore a wise and important precaution,” he concluded.

LOW-SUGAR AND ARTIFICIALLY SWEETENED DRINKS LINKED WITH FATTY LIVER DISEASE

Substituting low-sugar or artificially sweetened drinks for sugary drinks does not protect against fatty liver disease, a large study from China suggests.

Both sugar-sweetened beverages and low- or non-sugar-sweetened beverages are significantly associated with a higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD), researchers reported in Berlin at UEG Week 2025.

In MASLD, fat accumulates in the liver, potentially causing hepatitis and liver failure. The fatty liver condition affects more than 30% of people worldwide and is a rapidly increasing cause of liver-related deaths.

The new study tracked 123,788 UK volunteers without liver disease at baseline. During a median 10.3 years of follow-up, participants periodically completed questionnaires about the food and drinks they regularly consumed.

Over the course of the study, 1,178 participants developed MASLD and 108 died from liver-related causes.

Intake of low- or non-sugar-sweetened beverages and sugar-sweetened beverages of more than 330 grams (11 ounces) per day was associated with significantly higher risks of developing MASLD.

Both beverage types were also associated with higher liver fat content, although a study like this cannot prove the drinks caused the liver disease.

Sugar-sweetened beverages “have long been under scrutiny, while their ‘diet’ alternatives are often seen as the healthier choice,” study leader Lihe Liu of the First Affiliated Hospital of Soochow University in Suzhou said in a statement.

“Our study shows that low- or non-sugar-sweetened beverages were actually linked to a higher risk of MASLD, even at modest intake levels,” she added.

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(Reporting by Nancy Lapid; Editing by Bill Berkrot)