According to a new investigation that involved rescue workers exposed to dust from the World Trade Center (WTC), metabolic syndrome biomarkers predict decline in lung function later in life following particulate exposure. Findings from the study were published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
327 non-smoking FDNY 9/11 rescue workers were enrolled to participate in a nested case-control investigation. Researchers measured metabolic syndrome biomarkers within six months of exposure to WTC dust. The measurements predicted a decline of forced expiratory volume in one second (FEV1) over the next 6 years.
Anna Nolan, M.D., M.S., assistant professor of Medicine and Environmental Medicine at NYU Langone Medical Center, explained:
"Study participants with dyslipidemia, elevated heart rate or elevated leptin levels had a significantly increased risk of developing abnormal lung function during follow-up. In contrast, elevated amylin levels reduced the risk of developing abnormal FEV1 levels."
The study was nested within a larger longitudinally followed cohort. Before 9/11 all participants had normal lung function. Cases (n =109 participants) were characterized as having FEV1 values below the lower limit of normal at follow-up, while controls (n = 218 participants) were defined as having FEV1 at or above the lower limit of normal. For 166 controls and 71 cases biomarkers were available. The researchers discovered that in the median 28 months from initial and follow-up examinations, lung function continually declined in cases, whereas in controls lung function improved.
After adjusting for age, race, body mass index and arrival time to the WTC, they found that:
- Dyslipidemia (triglycerides≥150mg/dL and HDL
- The odds were increased three times by elevated leptin (≥10,300 pg/mL)
- and more than two times for elevated heart rate (≥66 bpm)
- The odds of being a case decreased by 84% with elevated amylin levels (≥116 pg/mL)
"This is the first report in humans showing an association between amylin and lung function. There are amylin recpetors in the lungs, and amylin has been shown to reduce leptin resistance. The protection offered by amylin in this study may have been mediated by these effects.
These findings suggest that systemic inflammation, a hallmark of the metabolic syndrome, may play a role in promoting lung function impairment in patients with particulate exposure. Given the high prevalence of the metabolic syndrome in industrialized nations and the rising incidence in developing nations with high ambient particulate levels, the relationship between these disorders is of considerable importance."
The study had a few limitations, such as using a single cohort of rescue workers and therefore limiting the results extrapolation to other cohorts, and it did not explore other possible causes of lung dysfunction. The study also did not include an unexposed control group, which means that it needs a replication of these findings in populations with and without exposure to particulate matter.
Dr. Nolan, said:
"Our findings in WTC rescue workers highlights the importance of conducting rapid medical monitoring and sample banking following a disaster. If we can identify individuals at greater risk of developing lung function impairment, we can initiate appropriate interventions earlier."
Written by Grace Rattue