Symptoms and lung function decline in a middle-aged cohort of males and females in Australia.
BACKGROUND
The European Community Respiratory Health Survey is a major international study designed to assess lung health in adults. This Australian follow-up investigated changes in symptoms between sexes and the roles of asthma, smoking, age, sex, height, and change in body mass index (ΔBMI) on lung function decline (LFD), which is a major risk factor for chronic obstructive pulmonary disease (COPD).


METHODS
LFD was measured as the rate of decline over time in FEV1 (mL/year) (ΔFEV1) and FVC (ΔFVC) between 1993 and 2013. Multiple linear regression was used to estimate associations between risk factors and LFD, separately for males and females. Multiple logistic regression was used to assess sex differences and changes in respiratory symptoms over time.


RESULTS
In Melbourne, 318 subjects (53.8% females) participated. The prevalence of most respiratory symptoms had either remained relatively stable over 20 years or decreased (significantly so for wheeze). The exception was shortness of breath after activity, which had increased. Among the 262 subjects who completed spirometry, current smoking declined from 20.2% to 7.3%. Overall mean (± standard deviation) FEV1 declined by 23.1 (±17.1) and FVC by 22.9 (±20.2) mL/year. Predictors of ΔFEV1 in males were age, maternal smoking, and baseline FEV1; and in females they were age, ΔBMI, baseline FEV1, and pack-years in current smokers. Decline in FVC was predicted by baseline FVC, age, and ΔBMI in both sexes; however, baseline FVC predicted steeper decline in females than males.


CONCLUSIONS
Most respiratory symptoms remained stable or decreased over time in both sexes. Age, baseline lung function, and change in BMI were associated with the rate of decline in both sexes. However, obesity and personal smoking appear to put females at higher risk of LFD than males. Health promotion campaigns should particularly target females to prevent COPD.
Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Victoria, Australia.
Michael J
MJ
Abramson
Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Victoria, Australia.
Sonia
S
Kaushik
Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Victoria, Australia.
Geza P
GP
Benke
Department of Allergy, Immunology & Respiratory Medicine, The Alfred Hospital, University of Melbourne, Melbourne, Victoria, Australia.
Brigitte M
BM
Borg
Department of Epidemiology & Preventive Medicine, School of Public Health & Preventive Medicine, Monash University, Victoria, Australia.
Catherine L
CL
Smith
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia.
Shyamali C
SC
Dharmage
Department of Allergy, Immunology & Respiratory Medicine, The Alfred Hospital, University of Melbourne, Melbourne, Victoria, Australia.
Bruce R
BR
Thompson
D000328:Adult; D000367:Age Factors; D001249:Asthma / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D001827:Body Height; D015992:Body Mass Index; D005260:Female; D005541:Forced Expiratory Volume; D006304:Health Status; D054624:Health Status Disparities; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology*; D008297:Male; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology / Q000503:physiopathology; D013997:Time Factors; D014739:Victoria / Q000453:epidemiology; D014797:Vital Capacity
COPD; body mass index; cohort study; lung function; respiratory symptoms; tobacco smoking