body weight and body mass index ( bmi ) are independent risk factors for mortality in chronic obstructive pulmonary disease ( copd ) patients [ 1 , 2 ] .
we researched the relationships between possible nutritional parameters ( haemoglobin levels , serum albumin , blood urea nitrogen , creatinine , cholesterol , triglycerides , creatine kinase  a myocyte - derived enzyme ) and lung functions in copd .
spirometric , laboratory , and demographic data of 450 consecutive patients ( 348 men and 102 women ) , aged 39 to 84 years , were analysed retrospectively .
all the patients had copd , according to the gold consensus report   and chronic airflow limitation , defined as measured forced expiratory volume in one second ( fev1)/forced vital capacity ( fvc)<70 percent .
exclusion criteria were malignancy , tuberculosis , bronchiectasis , surgical operation within 6 months , severe endocrine , hepatic , or renal disorders . the best and technically acceptable spirometric data , height and weight data , and smoking habits of each patient were noted .
fvc , fev1 , fev1/fvc , maximum mid - expiratory flow ( mmef ) , and peak expiratory flow rate ( pef ) levels were recorded as pulmonary function parameters .
all spirometric values obtained were related to a reference value and expressed as a percentage of the predicted value .
serum albumin , blood urea nitrogen ( bun ) , creatinine , cholesterol , triglycerides , creatine kinase , haemoglobin levels and pulmonary function test results were recorded when the patients were in a stable period .
a non - copd group consisted of the patients who had not airway obstruction ( fev1/fvc>70% ) .
all statistical analyses were performed with spss version 10.0 ( spss inc , chicago , il ) .
data were analysed using independent - samples t test , and pearson s correlation test , and spearman rank correlation test if the population was non - parametric .
if correlation coefficient was less then 0.3 , the results were considered as non - significant .
the study was approved by the ethical committee of the school of medicine , cumhuriyet university ( 2005 - 2/2 ) .
the mean age years of 102 females ( 22.7% ) and 348 males ( 77.3% ) were 62.9  0.8 and 61.4  0.5 respectively ( p>0.05 ) .
a non - copd group , consisted of 103 males ( 77.4% ) and 30 females , was gender- and age - matched .
demographic , spirometric , and biochemical parameters of two groups were presented in table  1 .
the patients who had airway obstruction had significantly greater pack - years of smoking , blood urea nitrogen and serum creatinine levels but lower bmi . when compared to female patients with copd , males had significantly greater pack - years of smoking , haemoglobin levels , more severe airway obstruction but lower bmi ( table  2 ) .
the prevalence of a bmi less than 20 kg.m was 9.6% among the 450 outpatients studied , 13.9% in severe copd ( fev1<50% of reference ) and 4.0% in mild to moderate copd .
there was a negative correlation between bmi and pack - years of smoking in copd ( r : 0.24 , p<0.01 ) but not in non - copd group .
the decreasing effect of smoking on bmi was valid only in copd group ( odds ratio : 1.41 , 95% confidence intervals : 1.22 - 1.63 ) .
for the relationships between bmi and pulmonary functions , the correlation coefficients were 0.21 for fvc , 0.26 for fev1 , and 0.32 for fev1/fvc in copd group . in non - smokers ,
bmi was significantly lower in men independent of age and pulmonary functions ( table  3 ) . in the entire copd group ( table  4 ) and in non - smokers ( table  5 ) , bmi was not related any of pulmonary functions .
multiple linear regression analysis revealed that serum albumin level was the best predictor of fev1 ( beta = 12.307 , p<0.001 ) .
creatine kinase levels showed no correlation any of the pulmonary function parameters ( data not shown ) .
table 1 showed that the patients with copd had significantly greater pack - years of smoking but lower bmi .
this finding suggests that the lower bmi is due to the loss of lung functions .
the higher correlation coefficients between bmi and lung functions than those between bmi and smoking also support this idea .
table  2 demonstrated that males had more severe loss of pulmonary parenchyma because they had greater load of smoking than females .
schols et al .   reported that serum albumin levels are positively associated with exercise performance , katsura et al .   found that low serum albumin can be a risk factor for poor outcome in copd .
this finding suggests that systemic catabolic process in copd affects serum albumin concentration more than bmi .
additionally , table  3 showed that bmi was significantly lower in male than in female in non - smokers subset .
males were more susceptible to weight loss and protein degradation despite the anabolic effects of testosterone .
another explanation is the different aetiology of copd . in our study , females had a history of tobacco use of less than 5.5 pack - years .
however , the minimum requirement is 10 pack - years for the development of copd in most clinical trials .
.   demonstrated that biomass fuel exposure could cause chronic airway obstruction in our region .
possibly copd due to biomass exposure can lead to different systemic effects than tobacco - induced copd .
the effect of malnutrition on pulmonary function is mediated in part by its effect on respiratory muscles .
arora and rochester   showed that nutritional depletion reduced respiratory muscle strength in patients without lung disease .
on the other hand , skeletal muscle weakness is frequently observed in patients with copd , and is associated with wasting of extremity fat - free mass .
depletion of fat - free mass , indicating loss of muscle mass , plays a pivotal role in exercise tolerance . in this study , we assessed serum creatine kinase levels to evaluate myocyte dysfunction .
however , we did not find a correlation between this muscle - derived parameter and pulmonary functions because serum creatine kinase is not a specific marker for malnutrition . in conclusion , nutritional depletion
is associated with impaired pulmonary functions in copd . when compared to controls , rising levels of bun and serum creatinine suggest a protein catabolism in patients with copd .
serum albumin concentration is more accurate parameter than bmi for assessing pulmonary dysfunction due to catabolic process in copd .
 the aim of this study was to reveal the relationships between nutritional parameters and pulmonary functions in patients with chronic obstructive pulmonary disease ( copd ) in both sexes . 
 spirometric , laboratory , and demographic data of 450 consecutive patients were analysed retrospectively . 
 males had significantly greater pack - years of smoking , more severe airway obstruction , and lower body mass index ( bmi ) . in non - smokers , 
 bmi was significantly lower in men independent of age and pulmonary functions . 
 creatine kinase levels showed no correlation with any pulmonary function parameters . 
 serum albumin levels correlated better than bmi with pulmonary functions . in conclusion , 
 females with copd were maintained weight better than men . 
Introduction
Materials and Methods
Results
Discussion