Our surrounding environments play a quiet but powerful role in our health.
From microscopic particles in the air we breathe, to rising temperatures, to microplastics we may swallow or inhale without noticing, environmental exposures are increasingly recognized as factors that can influence disease risk across the lifespan.
Recent research from Mass General Brigham investigators highlights how each of the above factors may affect reproductive, respiratory, and overall health. Together, these studies paint a growing picture of how environmental conditions can interact with the body in ways scientists are only beginning to fully understand.
The Environment May Be Harming Male Fertility
A recent review published in Current Opinion in Urology by Mass General Brigham investigators shows growing evidence that environmental changes may be contributing to declining male fertility worldwide. Over the past several decades, studies have documented drops in sperm count and sperm quality across many regions. While the causes are likely complex, the researchers, led by Alexandra Berger, MD, point to several possible environmental contributors.
The review highlights research showing that heat stress, from rising outdoor temperatures or sources such as saunas, can interfere with sperm production, which functions best at slightly cooler temperatures than the rest of the body. It also summarizes evidence linking fine air pollution particles, microplastics commonly found in air, water, and food, and hormone- disrupting chemicals to reduced sperm movement, lower sperm counts and DNA damage.
While human data are still limited, the authors conclude that environmental exposures are a plausible contributor to declining male fertility and call for more research to better understand these risks and how to reduce them.
Microplastics and Their Effects on Human Health
In a recent review published in JAMA, researchers at Mass General Brigham and Harvard T.H. Chan School of Public Health examine growing evidence that microplastics are entering the human body and may pose risks to human health. Microplastics are tiny plastic particles that form as larger plastic materials that break down in the environment. As global plastic production has increased, these particles have become widespread in air, water, food and many everyday products, leading to routine exposure through breathing and ingestion.
The review, led by Shruthi Mahalingaiah, MD, MS, summarizes studies showing that microplastics have been detected in a wide range of human tissues, including the lungs, blood, brain, placenta and reproductive organs, with some evidence suggesting levels have increased over time.
Laboratory and animal studies indicate that microplastics can trigger inflammation, oxidative stress, immune responses and cellular damage. Early human studies have also found associations with higher risks of cardiovascular and neurological conditions, though these findings do not yet establish cause and effect. The authors emphasize the need for more research to better understand associated health impacts, improve detection methods and reduce plastic pollution through stronger policies and safer alternatives.
What the Environment May Have to Do With Polycystic Ovary Syndrome
A recent review in Seminars in Reproductive Medicine, led by Mass General Brigham’s Shruthi Mahalingaiah, MD, MS, explores whether environmental exposures may play a role in polycystic ovary syndrome, or PCOS, the most common hormonal disorder affecting women of reproductive age. PCOS affects an estimated 10-15 percent of women worldwide and is associated with irregular menstrual cycles, infertility, hormone imbalances and metabolic conditions such as insulin resistance and type 2 diabetes. While genetics and lifestyle factors are known contributors, researchers are increasingly examining how environmental factors may influence disease risk and severity.
The review summarizes research linking PCOS to a range of environmental exposures, including air pollution, micro and nanoplastics, heavy metals, and hormone disrupting chemicals found in plastics, pesticides, and personal care products. Some studies suggest that exposure to certain air pollutants may increase PCOS risk, while animal studies indicate that microplastics can disrupt ovarian function. Evidence related to heavy metals and endocrine- disrupting chemicals is mixed, but some exposures have been linked to inflammation, oxidative stress, and metabolic changes associated with PCOS.
In all, the study stresses that environmental exposures are a plausible but understudied contributor to PCOS, and that there’s a need for long-term human studies that examine exposure timing across the lifespan.
How Air Pollution Affects the Nose and Sinuses
In a recent study published in International Forum of Allergy and Rhinology, Mass General Brigham investigators, led by corresponding author Regan Bergmark, MD, MPH, summarize growing evidence that air pollution plays a role in diseases of the upper airway, including allergic and non-allergic rhinitis and chronic rhinosinusitis. Research shows that common air pollutants, particularly fine particulate matter, ozone, nitrogen dioxide and sulfur dioxide, are associated with increased inflammation in the nose and sinuses. Exposure can occur indoors and outdoors through traffic pollution, wildfires, industrial emissions, cooking fumes and workplace environments.
The authors explain that air pollution can damage the protective lining of the upper airway, trigger immune responses and drive chronic inflammation that worsens symptoms and disease severity. Higher pollution levels have been linked to increased rates of rhinitis, sinus infections, emergency department visits and more severe chronic sinus disease.
The study also highlights emerging tools such as wearable air quality monitors, along with practical strategies to reduce exposure, including indoor air filtration and protective masks. Overall, the authors emphasize that air pollution is an important and often overlooked contributor to upper airway disease and underscore the need for both individual action and stronger air quality policies.
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