Restrictive spirometric pattern in the general adult population: Methods of defining the condition and consequences on prevalence.
Attempts have been made to use dynamic spirometry to define restrictive lung function, but the definition of a restrictive spirometric pattern (RSP) varies between studies such as BOLD and NHANES. The aim of this study was to estimate the prevalence and risk factors of RSP among adults in northern Sweden based on different definitions.



In 2008-2009 a general population sample aged 21-86y within the obstructive lung disease in northern Sweden (OLIN) studies was examined by structured interview and spirometry, and 726 subjects participated (71% of invited). The prevalence of RSP was calculated according to three different definitions based on pre-as well as post-bronchodilator spirometry: 1) FVC < 80% & FEV1/FVC > 0.7 2) FVC < 80% & FEV1/FVC > LLN 3) FVC < LLN & FEV1/FVC > LLN RESULTS: The three definitions yielded RSP prevalence estimates of 10.5%, 11.2% and 9.4% respectively, when based on pre-bronchodilator values. The prevalence was lower when based on post-bronchodilator values, i.e. 7.3%, 7.9% and 6.6%. According to definition 1 and 2, the RSP prevalence increased by age, but not according to definition 3. The overlap between the definitions was substantial. When corrected for confounding factors, manual work in industry and diabetes with obesity were independently associated with an increased risk for RSP regardless of definition.



The prevalence of RSP was 7-11%. The prevalence estimates differed more depending on the choice of pre- compared to post-bronchodilator values than on the choice of RSP definition. RSP was, regardless of definition, independently associated with manual work in industry and diabetes with obesity.
Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine/the OLIN unit, Umeå University, Umeå, Sweden. Electronic address: helena.backman@nll.se.
Helena
H
Backman
Department of Internal Medicine, Central County Hospital of Halmstad, Halmstad, Sweden; Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
Berne
B
Eriksson
Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine/the OLIN unit, Umeå University, Umeå, Sweden; Department of Health Sciences, Division of Nursing, Luleå University of Technology, Luleå, Sweden.
Linnea
L
Hedman
Department of Health Sciences, Division of Nursing, Luleå University of Technology, Luleå, Sweden.
Caroline
C
Stridsman
Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine/the OLIN unit, Umeå University, Umeå, Sweden.
Sven-Arne
SA
Jansson
Dept of Clinical Physiology and Nuclear Medicine, HUS Medical Imaging Centre, Helsinki University Central Hospital, Helsinki, Finland.
Anssi
A
Sovijärvi
Department of Public Health and Clinical Medicine, Division of Medicine/the OLIN unit, Umeå University, Umeå, Sweden.
Anne
A
Lindberg
Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine/the OLIN unit, Umeå University, Umeå, Sweden.
Eva
E
Rönmark
Department of Public Health and Clinical Medicine, Division of Occupational and Environmental Medicine/the OLIN unit, Umeå University, Umeå, Sweden; Krefting Research Centre, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden.
Bo
B
Lundbäck
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology*; D012015:Reference Standards; D012016:Reference Values; D012129:Respiratory Function Tests / Q000379:methods*; D012307:Risk Factors; D013147:Spirometry / Q000379:methods* / Q000639:trends; D013548:Sweden / Q000453:epidemiology; D014109:Total Lung Capacity / Q000502:physiology*; D014797:Vital Capacity / Q000187:drug effects* / Q000502:physiology
General population; Prevalence; Restriction; Risk factor; Spirometry