Infections caused by nontuberculous mycobacteria (NTM) are becoming more common around the world. When NTM affects the lungs, it can lead to a range of different health outcomes or results, but we still do not fully understand what influences how the disease develops. These bacteria are hard to treat because they do not respond well to many antibiotics (the medicine used to treat infections from bacteria), and treatment often takes a long time and can cause side effects. In the United States, most people who get NTM lung infections are women who do not have a history of lung disease or smoking. However, in other countries, the disease is more common in men, especially those who have had tuberculosis or smoked in the past.

In this study, we looked at whether there are differences in lung scans and symptoms between men and women with NTM infections. We found that men were more likely to have severe infections that do not respond well to treatment and show more extensive lung damage (cavitary disease). Women were more likely to have acid reflux, a hiatal hernia, and lung scarring (fibrosis). Because NTM infections are on the rise, more research is needed to understand how the disease develops, why it affects people differently, and how to treat it more effectively.

COPD is diagnosed with a pulmonary function test called spirometry. With spirometry, 2 specific things are measured: how much air an individual can blow out or exhale in 1 second (forced expiratory volume in 1 second—FEV₁) and the total amount of air an individual can exhale (forced vital capacity) after a deep breath in. These 2 measurements are put in a ratio: FEV₁ divided by FVC—and a measurement above .70 (or 70%) is considered normal. This is called the fixed ratio. The FEV₁ divided by FVC ratio may also be compared to the lower limit of normal. The lower limit of normal is adjusted for age, sex, height, and race of the individual taking the pulmonary function test. The lower limit of normal is a measurement of lung function that 95% of healthy people (with similar characteristics as the individual taking the test) would have. So, an individual’s lung function is considered not normal if it falls in the bottom 5% of results for their group.

Some individuals’ lung function falls between these 2 measurements. Specifically, their FEV₁/FVC value lies below the 0.70 normal measurement of the fixed ratio but above the lower limit of normal. Studies have shown that individuals who fall within this group have a worse outlook for the future. Information about how to treat this group is lacking.

In this study, we found that tiotropium treatment improved lung function, slowed lung function decline, and reduced flare-ups or exacerbations in patients with lung function measurements between the fixed ratio and the lower limit of normal.

This study looked at whether body weight is linked to how people’s lungs respond to a bronchodilator, a medicine that helps open the airways. We analyzed lung function and body mass index (BMI; an estimate of an individual’s body fat based on their height and weight) from more than 7000 adults living in Peru, Chile, Uruguay, and Argentina. A bronchodilator response was defined as a measurable improvement in lung function after using an inhaled medication. Overall, about 1 in 10 adults showed a bronchodilator response. We found that people with obesity (those with a BMI ≥30) were more likely to have a type of response that reflects improvement in the amount of air they can forcibly blow out (called the forced vital capacity on a lung function test ), which may relate to how extra body weight affects lung expansion and air trapping. In contrast, people with a low BMI (<20) who had asthma or chronic bronchitis were more likely to show a different kind of response (in lung function test called forced expiratory volume in 1 second ), which may be more sensitive to changes in airway narrowing.

These results suggest that body weight influences bronchodilator responsiveness in different ways. Both high and low BMIs may affect lung function, especially in people with underlying respiratory diseases. Understanding these patterns can help clinicians to better interpret lung tests and adapt treatments accordingly

Chronic obstructive pulmonary disease (COPD) is a serious lung condition that makes breathing difficult. Two common forms are emphysema, where the air sacs in the lungs are damaged, and chronic bronchitis, where too much mucus builds up in the airways. These were once thought to be separate conditions, but new research shows there can be overlap. Doctors have recently begun focusing on mucus plugs—thick clumps of mucus that completely block parts of the airways and can be seen on computed tomography or CT scans. Even though they do not always cause symptoms, mucus plugs are linked to worse health and a higher risk of death.

In this study, we examined 127 people with very advanced emphysema. We reviewed their CT scans for mucus plugs and compared the findings with their body weight, lung function, and quality of life. We found that about half had no plugs, while the other half had moderate to severe amounts of plugs. Patients with more plugs had worse lung function and a lower body mass index (BMI; a measurement using height and weight to estimate an individual’s body fat).A lower BMIis a known risk factor for poor health results or outcomes in patients with COPD. This suggests that mucus plugs may be an important warning sign and could help doctors tailor treatments more precisely in the future.

Emphysema—a form of chronic obstructive pulmonary disease (COPD)—damages tiny air sacs in the lungs. There are tests used to diagnose emphysema that measure how well an individual’s lungs are able to transfer gases like oxygen from the lungs into the bloodstream. In the carbon monoxide diffusing capacity test, a small, safe amount of carbon monoxide is breathed in and then traced or measured in the blood. This can tell how effective the lungs are at transferring other gases like oxygen into the blood stream and can help in diagnosing emphysema.

In this study, we asked whether a less commonly used gas-transfer test—the nitric oxide diffusing capacity test—can detect emphysema in smokers better than the traditional carbon monoxide diffusing capacity test. We analysed 408 smokers: 85 had emphysema on chest scans and 323 did not; all performed the same 10-second simultaneous nitric‑oxide/carbon‑monoxide breath‑hold maneuver.

The simplest, best-performing way to separate smokers with emphysema from those without used 3 measures, in order of importance: (1) how much air one can forcefully blow out in 1 second, (2) nitric‑oxide diffusing capacity, and (3) total lung capacity—how much air your lungs can hold. This 3-measure approach worked well. Adding the carbon monoxide diffusing capacity test did not improve the accuracy of the results. What this means: The nitric‑oxide diffusing capacity test adds valuable information and could help doctors spot emphysema earlier, especially in people with smoking histories. Wider use will require affordable, accessible equipment.

Statins are medicines that help reduce lipids in the blood—specifically, they reduce “bad” or LDL cholesterol, lowering the risk for heart disease. Some studies suggest that statins could reduce the risk of chronic obstructive pulmonary disease (COPD). It is unclear if this possible effect is related to their ability to lower lipids.

This study set out to clarify this possible association. We used a type of research or statistics method called Mendelian randomization to determine if there was a direct relationship between lipid levels in the blood and an individual’s risk of developing COPD. Mendelian randomization uses the differences in genes that people are randomly given at birth to determine if their gene mutation actually causes a condition they may have. We also used Mendelian randomization to look at the genes that cholesterol-lowering drugs (statins) target, to determine if there was a relationship between these genes and the development of COPD.

Our Mendelian randomization showed a direct relationship between low-density lipoprotein cholesterol (LDL-C) and a reduced risk of COPD. Direct or causal relationships were also identified for 2 lipid-lowering genes, HMGCR and PCSK9, and a reduced COPD risk. This study genetically identified causal relationships between LDL-C levels in the blood, the 2 coding genes HMGCR and PCSK9, and a reduced risk of COPD.

Chronic obstructive pulmonary disease (COPD) is a long-term lung condition affecting the airways that makes it difficult to breathe. Some people with COPD have high levels of eosinophils, a white blood cell involved in inflammation. This eosinophilic COPD subtype may respond differently to treatment. In asthma, a different airways disease, the fractional exhaled nitric oxide test is used to detect airway inflammation, especially eosinophilic inflammation, but its role in COPD is less clear.

In this study, 176 former smokers with eosinophilic COPD had both fractional exhaled nitric oxide levels and blood eosinophil counts measured. Participants with higher eosinophil counts or a history of asthma generally had higher fractional exhaled nitric oxide levels also. Those with elevated fractional exhaled nitric oxide levels were also somewhat more likely to have been hospitalized for COPD in the past year, though results did not reach statistical significance.

These findings suggest that the fractional exhaled nitric oxide test, a simple and noninvasive test, may help identify patients with eosinophilic COPD who are at greater risk of hospitalization. Further research is needed to confirm these results and determine whether routine fractional exhaled nitric oxide measurement could guide treatment and preventive measures and improve results for this subgroup of COPD patients.