Raised Omega-3 Fatty Acid Levels Linked to Reduced Respiratory Events

May 20, 2020
Kevin Kunzmann

A new assessment shows risk reduction is even more significant among COPD patients who have smoked.

Greater levels of omega-3 polyunsatured fatty acids are associated with slower emphysema progression, as well as lowered risk for chronic lower respiratory disease (CLRD), in patients with chronic obstructive pulmonary disease (COPD).

New findings, originally planned for presentation at the American Thoracic Society (ATS) 2020 International Conference this year, show an association between increased omega-3 fatty acid levels and reduced risk of COPD-related events.

A team of US-based investigators sought to understand the association of higher plasma levels of omega-3 polyunsaturated fatty acids (n-3 PUFAs) with a series of indicated metrics for protection in patients with COPD: slow progression of percent emphysema on computed tomography (CT) tests, slower decline in lung function, and lowered risk of CLRD events.

Investigators conducted a longitudinal cohort assessment (MESA) of 6573 US community-dwelling adults aged 45-84 years during the enrollment period of 2000-2002, who had phospholipid fatty acids measured from baseline plasma samples. Patients were most recently examined at 2016-2018.

Participants were provided cardiac scans between 2000-2007, and full-lung CT scans between 2010-2018. During the latter period, emphysema was assessed—and defined as < -950 Hounsfield Units. Spirometries were performed at follow-up visits from 2004-2018.

Investigators used linear mixed models to examine associations of n-3 PUFA levels with change in percent emphysema and spirometry. Models were adjusted for age, sex, race and ethnicity, smoking status, cigarette pack-years, cigarettes per day, insurance type, height, weight, education, COPD genetic risk score, and other factors.

The team also adjusted percent emphysema models for scanner type and radiation dose.

Cox proportional hazard models were used for the examined association of omega-3 fatty acid levels, expressed as percentage of total fatty acids, with CLRD events, defined as hospitalization and death.

Patients reported mean plasma docosahexaenoic (DHA), eicosapentaenoic (EPA), and docosapentaenoic acid (DPA) levels of 3.8%, 0.9%, and 0.9%, respectively. Over a mean follow-up of 12 years, higher total n-3 plasma levels, as per DHA+EPA+DPA, were associated with a slowed adjusted progression of percent emphysema (-0.51% relative change in percent emphysema per log-transformed total n-3 increment; 95% CI, -0.99 to -0.03).

Investigators observed strong association among ever smokers versus never smokers, though there was no associated between n-3 PUFA levels and spirometry. Greater fatty acid levels were associated with nearly halved CLRD event risk (HR, 0.53 per log-transformed total n-3 increment; 95% CI, 0.43-0.67).

Among patients with COPD, higher fatty acid level-associated risk was more than halved (HR, 0.45; 95% CI, 0.31-0.66). The association was less significant, but still notable, among patients with asthma (HR, 0.74; 95% CI, 0.54-1.01).

Per CLRD events, fatty acid levels were associated with even stronger risk reductions among ever smokers (adjusted HR, 0.45; 95% CI, 0.31-0.66).

“Higher plasma n-3 PUFA levels were associated with a slower progression of percent emphysema and a lower risk of CLRD events among community-dwelling adults,” investigators concluded.

The study, “Associations of Plasma Omega-3 Fatty Acid Levels with Longitudinal Change in Percent Emphysema, Spirometry, and Chronic Lower Respiratory Disease Events: The Mesa Lung Study,” was published online.