A new study shows that losing weight and treating excessive blood lipid levels can help prevent lung disease in firefighters who were exposed to dangerous levels of fine particles from fire, smoke and toxic chemicals on September 11, 2001.
Experts have long wondered whether this toxic exposure would later lead to lung disease in first aiders. A high body mass index (BMI), an indicator of obesity, combined with exposure to the highest levels of toxin from the World Trade Center attack, were the two biggest risk factors for decreased lung function, according to the study authors.
After two decades of research analyzing thousands of first responders, a new study led by researchers at the NYU Grossman School of Medicine identified a group of five factors that predicted lung disease in these patients. Along with excess body fat, the combination of insulin resistance, high blood pressure, and increased levels of sugar and cholesterol in the blood are components of what is known as metabolic syndrome, a group of medical problems known to increase the risk of heart disease and stroke, and diabetes.
Adjusting for at least one of these factors, the study researchers said, can significantly lower the risk of firefighters developing lung disease within 5 years, even 20 years of toxic ground zero exposures. For example, a male firefighter of average height, losing 7 pounds of weight could reduce his risk of lung injury by 20 percent.
Our results should reassure World Trade Center first responders that there are steps they can take to protect their lungs decades after exposure. “
Sophia Kwon, DO, MPH, co-lead author of the study
Dr. Kwon is a fellow in the Department of Pulmonary, Critical Care, and Sleep Medicine at NYU Langone Health.
In a paper presented to 100 overweight 9/11 firefighters earlier this year, the team found that a low-calorie Mediterranean diet containing unrefined grains, olive oil, fruits, and fish reduced the risk of lung disease. Those who followed the regimen for 6 months lost nearly 2 BMI points (from an average BMI of around 33 to an average of 31) and had fewer signs of lung disease than they reported prior to the study period.
“These results provide firefighters with a tangible way to lose weight and achieve the lung health benefits predicted by our risk model,” said study co-lead George Crowley, BA, a graduate student at NYU Langone.
Experts had previously understood that first responders who developed metabolic syndrome shortly after 9/11 were more likely to have a higher rate of asthma. However, the risks of lung injury for a firefighter whose metabolic syndrome instead appeared later in life have remained unclear.
The new study, published online September 2 in the American Journal of Respiratory and Critical Care Medicine, is part of what is probably the longest-running and most in-depth study of the effects of metabolic syndrome on lung injuries in firefighters, dated the 11th of the study. In addition, the study is the first to date to quantify how adjusting one or more of these risk factors changes the risk of lung disease.
For the study, the research team analyzed data from more than 5,700 firefighters who were active on September 11 for 20 years, 1,475 of whom later developed a lung disease. In addition to BMI, the data collected included smoking history and whether they had served in the World Trade Center in the early morning when pollution levels peaked.
“The lessons of our research apply not only to firefighters, but also to the millions of city dwellers who are exposed to air pollution on a daily basis,” said study lead author and pulmonologist Anna Nolan, MD. “They should be aware that while there are real health risks in their surroundings, even if they cannot change their exposure, they can minimize their risk of lung disease.”
Dr. Nolan, a professor in NYU Langone’s Department of Medicine and Department of Environmental Medicine, warns that while the Mediterranean diet research looks promising, it is only examining a small, specific group.
Next, the research team plans to expand the study to see if the diet could benefit a more diverse population similarly exposed to urban pollutants. They also plan to study how metabolic syndrome can affect other measures of lung function, such as asthma, says Dr. Nolan.
Kwon, S., et al. (2021) Dynamic Metabolic Risk Profile of World Trade Center-Lung Disease: A Longitudinal Cohort Study. American Journal of Respiratory and Critical Care Medicine. doi.org/10.1164/rccm.202006-2617OC.