FEV1 decline in relation to blood eosinophils and neutrophils in a population-based asthma cohort

• Background: The relationship between lung function decline and eosinophils and neutrophils has important therapeutic implications among asthmatics, but it has rarely been studied in large cohort studies.Objective: The aim is to study the relationship between blood eosinophils and neutrophils and FEV1 decline in a long-term follow-up of a population-based adult asthma cohort.Methods: In 2012-2014, an adult asthma cohort was invited to a follow-up including spirometry, blood sampling, and structured interviews, and n = 892 participated (55% women, mean age 59 y, 32-92 y). Blood eosinophils, neutrophils and FEV 1 decline were analyzed both as continuous variables and divided into categories with different cut-offs. Regression models adjusted for smoking, exposure to vapors, gas, dust, or fumes (VGDF), use of inhaled and oral corticosteroids, and other possible confounders were utilized to analyze the relationship between eosinophils and neutrophils at follow-up and FEV1 decline.Results: The mean follow-up time was 18 years, and the mean FEV 1 decline was 27 ml/year. The annual FEV1 decline was related to higher levels of both blood eosinophils and neutrophils at follow-up, but only the association with eosinophils remained when adjusted for confounders. Further, the association between FEV1 decline and eosinophils was stronger among those using ICS. With EOS <0.3 × 109/L as reference, a more rapid decline in FEV1 was independently related to EOS ≥0.4 × 109/L in adjusted analyses.Conclusions and clinical relevance: Besides emphasizing the importance of smoking cessation and reduction of other harmful exposures, our real-world results indicate that there is an independent relationship between blood eosinophils and FEV1 decline among adults with asthma.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Lungmedicin och allergi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Respiratory Medicine and Allergy (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Omvårdnad (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Nursing (hsv//eng)

Keyword

ANOVA

Analysis of variance

ATS

American Thoracic Society

Asthma

BMI

Body mass index

Cohort

ECRHS

European Community Respiratory Health Survey

EOS

Eosinophils

ERS

European Respiratory Society

Eosinophils

FEV1

FEV1

Forced Expiratory Volume in 1 s

FEV1pp

FEV1 percent of predicted

FVC

Forced Expiratory Volume

GLI

Global Lung function Initiative

ICS

Inhaled corticosteroids

IgE

Immunoglobulin E

L

Liters

Ml

Milliliters

N

Number

NEU

Neutrophils

Neutrophils

OCS

Oral corticosteroids

OLIN

Obstructive Lung Disease in Northern Sweden

OLS

Ordinary Least Squares

VGDF

Vapors

gas

dust or fumes

Nursing

Asthma

Cohort

Eosinophils

FEV1

Neutrophils

adult

aged

Article

cohort analysis

eosinophil

female

follow up

forced expiratory volume

human

human cell

major clinical study

male

neutrophil

priority journal

Publication and Content Type

ref (subject category)

art (subject category)