Focus on Early COPD: Definition and Early Lung Development

Figures & data

Table 1 Definition of Mild COPD and Early COPD

Mild COPD	Early COPD
1) FEV1/FVC<70% (post–bronchodilators) 2) FEV1>80% predicted value	1)>50 year of age and smoking>10 packs/year 2) Meet any of the following: FEV1/FVC<LLN (post–bronchodilators); Chest CT showed small airway obstruction or thickened airway walls; Lung function reduced rapidly; with the decline in FEV1>60mL/year

Note: Other known chronic lung diseases were excluded except for asthma.

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; LLN, lower limit of normal; COPD, chronic obstructive pulmonary disease; CT, computer tomography.

Table 2 Disadvantages and Future Directions for Early COPD

Early COPD	Disadvantages	Future
1)<50 year of age and smoking>10 packs/year	● Age < 50 years should be adjusted earlier. ● Smoking exposure should be redefined. ● 25–45% with COPD are non-smokers, resulting in missed diagnosis in some patients.	● Adjust the range of age and number of cigarettes smoked. ● Antenatal and childhood risk factors should be added in early COPD.
2) Meet any of the following:
FEV1/FVC<LLN (post-bronchodilators);	● LLN is the value before the inhalation of bronchodilators.	● Change post-bronchodilators to prebronchodilators.
Chest CT showed small airway obstruction or thickened airway walls;	● The threshold for CT scan abnormalities are not clear.	● More studies are needed to clarify thresholds.
Lung function reduced rapidly; with the decline in FEV1>60mL/year;	● FEV1 can also decrease with acute pulmonary inflammation, but it can later return to normal. ● The majority of adult COPD patients progress without accelerated decline in lung function. ● Symptomatology is an important basis of COPD.	● The duration of FEV1 decrease by 60mL/year should be specifically defined. ● The symptoms (cough or sputum production) should be considered.

Abbreviations: FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; LLN, lower limit of normal; COPD, chronic obstructive pulmonary disease; CT, computer tomography.

Figure 1 Natural history of lung function and risk factors at different stages. This figure shows the developmental trajectory of lung function, which is influenced by prenatal and postnatal factors. Reprinted with permission from Rennard SI, Drummond MB. Early chronic obstructive pulmonary disease: definition, assessment, and prevention. Lancet. 2015;385(9979):1778–1788. Copyright 2015 Elsevier Ltd. All rights reserved.²³

Abbreviations: FEV1, forced expiratory volume in 1 second; LBW, low birth weight.

Table 3 Risk Factors for Lung Development at Different Life Stages

The Stage of Life	The Risk Factors for Lung Function
Genetics	α1-antitrypsin deficiency
	ADAM33, SOX5, TNS1
Antenatal period	Maternal smoking
	LBW/VLBW, Preterm birth
	Maternal nutrition
	Mode of delivery Vitamin D deficiency
Childhood	Childhood smoking
	Air Pollution
	Childhood respiratory infections
	Childhood asthma Manual working class and overcrowding

Abbreviations: LBW, low birth weight; VLBW, very low birth weight.

Rennard SI, Drummond MB. Early chronic obstructive pulmonary disease: definition, assessment, and prevention. Lancet. 2015;385(9979):1778–1788. doi:10.1016/S0140-6736(15)60647-X

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