Smoking and obstructive lung dysfunction in persons with chronic spinal cord injury.
BACKGROUND
Persons with higher-level spinal cord injury (SCI) have reduced vital capacity and increased risk of respiratory symptoms and illness, with smokers experiencing excess vital capacity losses. To date, obstructive lung dysfunction, the most prominent effect of smoking in the able-bodied population, has not been characterized in persons with SCI.


OBJECTIVE
To determine whether smokers and/or nonsmokers with SCI are at increased risk to develop obstructive lung dysfunction, as measured by the ratio of forced expired volume in 1 second to forced vital capacity (FEV1/FVC).


METHODS
Regression analyses on cross-sectional data from routine clinical testing of outpatients followed at the Bronx Veterans Affairs Medical Center in metropolitan New York (NY) and Rancho Los Amigos National Rehabilitation Center in metropolitan Los Angeles (LA) tested the relationship of FEV1/FVC (percentage of predicted normal value) to age, SCI characteristics, and smoking status.


RESULTS
NY current smokers showed a significant (P < 0.01) excess decline in FEV1/FVC with increasing age; 35% fell below normal limits compared with 16% of NY former and never smokers. LA current smokers, who were generally younger and smoking less, showed a less clear age-related decline. Never smokers in NY or LA showed no age-related decline beyond that expected in the general population. Former smokers resembled never smokers, except that NY paraplegics showed borderline-significant (P = 0.09) excess age-related decline, which was less than that in NY current smokers.


CONCLUSIONS
Smokers with SCI appeared to be at excessive risk for obstructive lung diseases. Smoking cessation appeared to reduce the risk substantially. Careful longitudinal studies are needed to confirm these findings.
Linn
William S
WS
Rancho Los Amigos National Rehabilitation Center, Downey, California 90242, USA. linn@hsc.usc.edu
Spungen
Ann M
AM
Gong
Henry
H
Bauman
William A
WA
Adkins
Rodney H
RH
Waters
Robert L
RL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000503:physiopathology; D013119:Spinal Cord Injuries / Q000150:complications* / Q000503:physiopathology