“Many people don’t realize that these conditions are very common in ambulatory care,” said Michigan Medicine gastroenterologist Shirley Ann Cohen-Mekelburg, M.D., who specializes in conditions like inflammatory bowel disease, Crohn’s disease and ulcerative colitis.

“Ultimately, this creates an excess in health care spending in the United States. Not only are these conditions debilitating for the millions of people living with them, but they’re also very expensive to treat.”

Cohen-Mekelburg says that in recent years, there has been a greater emphasis among providers in detecting why so many Americans are developing digestive diseases.

However, she notes that current approaches often fail to consider how things like psychosocial factors contribute to these conditions.

“As physicians, it’s important for us to pay attention to psychosocial factors involved in the lives of our patients, but they often go overlooked,” she said.

“These factors have the potential to significantly impact gastrointestinal health, and they also play a crucial role in the overall wellbeing of our patients.”

This notion inspired Cohen-Mekelburg and a team of fellow gastroenterologists and hepatologists to examine the rates of loneliness, depression and social isolation in older adults both with and without digestive diseases.

Their findings were recently published in Clinical Gastroenterology and Hepatology.

Cohen-Mekelburg notes that the team also “wanted to quantify these numbers with self-reported rates of poor health.”

“Our research involved analyzing data from 2008 to 2016 from the University of Michigan Health and Retirement Study.

This is a longitudinal panel study that involves a representative sample of approximately 20,000 individuals in the U.S. who are 50 years and older, as well as their spouses,” she said.

“It’s important to note that loneliness refers to the subjective distressed feeling of being alone or lacking companionship. The correlation between loneliness and depression is well established.”

However, Cohen-Mekelburg adds that social isolation refers to the “objective physical separation from other people, which is independent of psychological well-being.”

“Therefore, there are people who live in isolation but are well-adapted, not lonely and report high psychological wellbeing. But on the other hand, there are also people who are socially connected, yet suffer from low psychological wellbeing and loneliness. This, despite having a strong social network.”

Out of a pool of 7,110 participants, the team identified 56% of individuals with a digestive disease and 44% without one.

“Overall, 60.4% and 55.6% of respondents with and without digestive diseases reported loneliness, while 12.7% and 7.5% reported severe depression, and 8.9% and 8.7% reported social isolation, respectively,” said Cohen-Mekelburg.

“We found that individuals with a digestive disease were more likely to report ‘poor-or-fair’ health when compared to those without one. And among patients with a digestive disease, loneliness, as well as moderate to severe depression, were associated with greater odds of self-reporting ‘poor-or-fair’ health.”

Cohen-Mekelburg says that she hopes these findings eventually empower gastroenterologists to “screen patients for depression and loneliness,” in addition to their physical symptoms. “By doing this, providers can better establish care pathways for mental health treatment for their patients, which is hugely important,” she said.

“Our research shows that gastroenterologists are in a unique position to help their patients achieve good overall health. If you’re a clinician who also happens to treat older adults, even better. Being aware of the link between loneliness, depressive symptoms and digestive diseases can really benefit your patients from a holistic perspective.”

In this study, scientists from the Biology of Intracellular Bacteria Unit, led by Carmen Buchrieser at the Institut Pasteur, in collaboration with Sophie Jarraud, Head of the National Reference Center for Legionella in Lyon, analyzed the diversity and composition of the respiratory tract microbiome (bacteria, archaea, fungi and protozoa) in patients with pneumonia caused by the intracellular bacterial pathogen Legionella pneumophila for their entire hospitalization period. L. pneumophila is responsible for a severe pneumonia known as Legionnaires’ disease, which can be contracted by inhaling contaminated aerosols from artificial water sources such as showers, hot tubs or air conditioning systems. The fatality rate for Legionnaires’ disease varies from 5 to 40% depending on the clinical context and the region. Risk factors are old age, pre-existing lung conditions, smoking and immunosuppression, and around two-thirds of reported cases occur in men. Confirmed cases of Legionnaires’ disease in the European Union went from 4,693 cases in 2005 to 10,004 cases in 2021, an increase of 113%. One of the reasons for this sharp rise may be climate change, with higher water temperatures and more frequent and intense floods that allow Legionella to replicate more rapidly and to access human environments.

The team of scientists combined high-throughput bacterial, archaeal and fungal marker gene sequencing with a quantification approach to characterize how the respiratory tract microbiome developed in patients over the course of infection and as a result of hospital-related interventions (such as mechanical ventilation and administration of antibiotics). A unique cohort of 38 hospitalized patients with pneumonia caused by Legionella pneumophila was analyzed. “We discovered complex microbiome dynamics, where commensal and pathogenic microorganisms coexist, and the equilibrium among their abundance drives the microbiome to recovery or dysbiosis,” explains Carmen Buchrieser, lead author of the study and Head of the Institut Pasteur’s Biology of Intracellular Bacteria Unit. The scientists observed that early in hospitalization, microbiome diversity decreased and the pathogen L. pneumophila was killed by the antibiotic treatment. But the empty niche was soon occupied by other opportunistic species, often resistant to antimicrobials — a factor that should be considered in prevention strategies for secondary infections. The respiratory tract microbiomes with the highest bacterial and fungal loads also showed lower diversity and pathogen enrichment, indicating that high biomass could be a biomarker for secondary and/or co-infections. Finally, the scientists showed that Legionella biomass correlates with disease severity and comorbidities, suggesting that pathogen quantification should be included in patient monitoring. Clinical interventions such as mechanical ventilation or administration of certain types of antibiotics influence the microbiome composition and therefore also disease outcome.

“In this study we also discovered that fungi, archaea and protozoa may be resident and not merely transitory in the respiratory tract of hospitalized patients and that they might contribute to pneumonia progression. This requires further investigation. Our research therefore shows that the interaction between respiratory tract microbiome equilibrium, pathogen load dynamics and clinical interventions plays a crucial role in the recovery of patients with pneumonia,” concludes Carmen Buchrieser.