The urban environment plays a significant role in the development of asthma, particularly in densely populated areas with limited green spaces. A recent study conducted by researchers from Karolinska Institutet has shed light on this issue, highlighting that nearly one in ten asthma cases can be avoided with a better urban environment.

The study, which involved over 350,000 people from seven European countries, analyzed the impact of air pollution, outdoor temperatures, and urban density on the risk of developing asthma. The researchers used satellite images to assess the environmental exposures, categorizing areas as grey (buildings), green (green spaces), or blue (water).

According to the study, nearly 7,500 participants developed asthma during the study period. The researchers found that 11.6% of these cases could be attributed to the combination of environmental factors, such as air pollution and lack of green spaces.

“This is a significant finding,” says Zhebin Yu, first author of the study. “Our research shows that by improving the urban environment, we can reduce the risk of asthma in children and adults.”

The study’s findings have important implications for urban planning and policy-making. By identifying areas with high environmental risks, policymakers can take steps to mitigate these risks and create healthier environments.

“The method used in this study can be applied to existing urban areas as well as new developments,” says Erik Melén, professor at the Department of Clinical Research and Education, Södersjukhuset, and last author of the study. “This will enable us to better understand how environmental factors contribute to disease development and inform strategies for prevention.”

The researchers plan to conduct further studies, including an examination of blood samples from some participants to identify their metabolome – a composite picture of the body’s metabolism and breakdown products.

This research has significant implications for our understanding of asthma development and may lead to new strategies for preventing this condition. By improving the urban environment, we can reduce the risk of asthma and create healthier communities.

The Fitness-Fatality Fallacy: Are We Overestimating the Effects of Physical Fitness on Mortality?

A new study published in the European Journal of Preventive Cardiology has shed light on a fascinating phenomenon: people with high fitness levels may have a lower risk of premature death, but this association might be more complex than we initially thought. The research, led by Marcel Ballin from Uppsala University, suggests that the associations seen in previous studies may have been misleading due to factors such as confounding variables and overestimation of effects.

The study leveraged data from 1.1 million Swedish men who were conscripted for military service between 1972 and 1995. The researchers divided the men into five groups based on their fitness level at the time, which was then followed until their 60s or until they died. By adjusting statistical models for factors such as BMI, age at conscription, year of conscription, and parents’ income and education level, the team found that the group with the highest fitness level had a significantly lower risk of dying from cardiovascular disease (58% lower), cancer (31% lower), and all causes (53% lower) compared to the group with the lowest fitness level.

However, when examining how fitness was associated with the risk of dying in random accidents such as car accidents, drownings, and homicides, the researchers found that men with the highest fitness levels had a 53% lower risk of dying in random accidents. This result, known as negative control outcome analysis, suggests that the association between physical fitness and mortality may not be as straightforward as previously thought.

The study also used sibling comparison design to control for factors shared by siblings, such as behaviors, environmental factors, and some genetic factors. The results were similar, with a strong association between fitness levels and accidental mortality.

This study is significant because it highlights the importance of using multiple methods to investigate associations and avoid overestimation of effects. By using different approaches, researchers can create a more nuanced understanding of how big the effects of fitness actually are on different outcomes.

The findings should not be interpreted as if physical activity and exercise are ineffective or that you should not try to promote it. However, large-scale interventions or policy changes intended to apply to the entire population must be based on reliable estimates – otherwise there is a risk of expecting effects that have in fact been overestimated.

Pregnant women who suffer from metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease, are more likely to give birth prematurely. A new study published in the journal eClinicalMedicine has found that these women have a significantly higher risk of preterm birth, and this increased risk cannot be attributed solely to their weight or obesity.

According to the research conducted by Karolinska Institutet, one in five people in Sweden may have MASLD, while globally, it could affect as many as three out of ten individuals. Common risk factors for developing the disease include metabolic disorders like type 2 diabetes and being overweight or obese. The study’s findings are based on Swedish registry data and included a total of 240 births among women with MASLD, along with 1140 matched births from the general population.

Alarmingly, the research revealed that women with MASLD were more than three times as likely to give birth prematurely compared to those without the disease. This increased risk persisted even after adjusting for factors such as weight and metabolic disorders. The study’s lead author suggests that this association may not solely be due to a high BMI, implying that the liver disease itself could have negative effects on pregnancy outcomes.

Moreover, women with MASLD had a 63 percent higher risk of caesarean section compared to the control group. However, this increased risk seemed to be explained by their high BMI, as no significant difference was observed when comparing them to overweight or obese women without fatty liver disease.

While the study’s findings are concerning, it is essential to note that MASLD itself did not increase the risk of congenital malformations in the children born to these women. The authors acknowledge that their research may have been influenced by other factors and emphasize the importance of closely monitoring pregnant women with MASLD to reduce the risk of complications.

The study’s conclusions highlight the need for specific recommendations regarding pregnancy care for women with MASLD, which could potentially be added to clinical guidelines for managing the disease.