Spirometric reference equations for older adults

The objective of this study was to develop spirometric reference equations for healthy, never-smoking, older adults. It was designed as a cross-sectional observational study consisting of 1510 Seventh Day Adventists, ages 43-79 years enrolled in a study of health effects of air pollutants. Individuals were excluded from the reference group (n = 565) for a history of current respiratory illness, smoking, or chronic respiratory disease, and for a number of 'non-respiratory' conditions which were observed in these data to be related to lower values of FEV1. Gender-specific reference equations were developed for the entire reference group and for a subset above 65 years of age (n = 312). Controlling for height and age, lung function was found to be positively related to the difference between armspan and height, and in males was found to be quadratically related to age. The predicted values for this population generally fell within the range of those of other population groups containing large numbers of adults over the age of 65 years. Individuals with lung function below the 5th percentile in this sample, however, could not be reliably identified by using the lower limits of normal predictions commonly used in North America and Europe.     

Spirometric function in children of Mexico City compared to Mexican-American children

We set out to describe the pattern of lung function growth in Mexican students from 8-20 years of age, using internationally accepted equipment and methodology, and to compare it to values reported for Mexican-American children. Out of a total of 6,803 students from primary school to high school studied cross-sectionally in the Mexico City metropolitan area, we selected 4,009 asymptomatic, nonobese, nonsmoker subjects to generate spirometric prediction equations. We describe regression equations for the main spirometric variables (log transformed) based on age, height, and weight, and separated for males and females. Spirometric function in the population studied was above that predicted for European (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142) or Mexican-American children, for the same age, height, and gender. On average, forced expiratory volume in 1 sec (FEV(1)) in Mexican children was 9.5% above that of Europeans (Quanjer et al. [1987] Pediatr Pulmonol 19:135-142), 14% and 5% above Hispanics reported by (Coultas et al. [1988] Am Rev Respir Dis 138:1386-1392) and (Hsu et al. [1979] J Pediatr 95:14-23), respectively, and 5% above Mexican-Americans from the third National Health and Nutrition Examination Survey study. Similarly, FVC was 8%, 14%, 8%, and 5.6% above the figures predicted by the same authors. The largest errors of prediction of foreign equations occurred in extremely tall or short subjects, and therefore a single proportional adjustment is unfeasible.     

Respiratory diseases and cigarette smoking in a Hispanic population in New Mexico

We have conducted a cross-sectional study of Hispanic residents of a community in New Mexico. A total of 2,111 subjects were recruited from 733 households; the overall participation rates were 68.1% for males and 78.9% for females. For all subjects, a standardized respiratory symptoms questionnaire was completed, spirometric testing was performed, and saliva and end-tidal breath samples were obtained. As in other populations, chronic respiratory symptoms were uncommon in children, and asthma was more prevalent in boys than in girls. In adults, physician-diagnosed chronic bronchitis and emphysema were less prevalent in this population than in a previously studied sample of non-Hispanic whites in New Mexico. Spirometric testing was confirmatory; less than 1% of the Hispanic males and females had chronic air-flow obstruction. The prevalence of cigarette usage in the Hispanics was comparable to data from non-Hispanic whites in New Mexico and from nationwide surveys. However, daily cigarette consumption by the Hispanics in this sample tended to be low, as found in previous studies in New Mexico and elsewhere.     

Salivary cotinine levels and involuntary tobacco smoke exposure in children and adults in New Mexico

We conducted a population-based household survey of respiratory disease in 2,029 children and adults and measured salivary cotinine levels by radioimmunoassay in 1,360 nonsmokers and ex-smokers. At all ages median and mean cotinine levels among nonsmokers and ex-smokers increased with the number of smokers in the home. The prevalence of a detectable level of cotinine was about 35% for those not living with a cigarette smoker and was greater with the number of cigarettes smoked by household members. In a multiple logistic regression model, the major determinants of a detectable level of cotinine in children were mother's smoking (odds ratio (OR) = 3.2), father's smoking (OR = 2.1), and smoking of other household members (OR = 4.0). Among adults, the effects of spouse's smoking were smaller with OR = 1.3 and 1.4 for husband's and wife's smoking, respectively. We conclude that in the general population cotinine can be frequently detected in the saliva of nonsmokers, even among those not living with a smoker.     

Spirometric reference values in Senegalese black adults

Spirometric volumes and expiratory flows were measured among 448 Senegalese males and females of 25-80 yrs of age. The values obtained are similar to those reported for black Africans and black Americans in the literature. Volumes are 15-25% lower in males and 23% lower in females than in Caucasians. Forced expiratory flow between 25-75% of vital capacity (VC), (FEF25-75) is 5-18% lower in males and 19% lower in females. FEF25-75/VC ratio is higher in blacks than in Whites, but the forced expiratory volume in one second FEV1/VC ratio is similar in black and white subjects. However, we cannot use proportional factors to determine spirometric black standards from white reference values, so, equations of regression and nomograms with age and height are proposed for black Africans.     

Spirometric reference values in Tunisian children

BACKGROUND: In Tunisia, there are no normal values of pulmonary function for healthy Tunisian children. OBJECTIVES: The purpose of this study was to set reference values for spirometric lung function in Tunisian children and to compare these results with other data sets. METHODS: Spirometric values were measured with a Minato portable spirometer in 1,114 asymptomatic, nonsmoking Tunisian children (581 boys and 533 girls) 6-16 years of age. Natural logarithmic values of lung function and standing height were used in the final regression model. RESULTS: Prediction equations for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), FEV(1)/FVC x 100, maximum mid expiratory flow (MMEF 25-75%) and peak expiratory flow (PEF) for both sexes are presented with standing height as the dependent variable. Our data show a significant increase in lung function with standing height in both sexes. Comparing our results with recent data, values of FVC and FEV(1) in both sexes in the present study are close to those in European, white US and Asian children, whereas our values are higher than the Libyan ones. CONCLUSIONS: Healthy Tunisian children showed similar spirometric reference values compared to European, white US and Asian children. Thus, these standards of lung function could also be used in Tunisia.     

Spirometric values in Gypsy (Roma) children

Values of spirometry indices vary among subjects of similar age, gender and somatometrics but of different ethnic origins. Low socioeconomic status in childhood is inversely related to lung growth. The aim of this investigation was to assess spirometry values in Gypsy children and compare them to reported values for Caucasians. Gypsy students attending primary schools in Central Greece were recruited. Spirometry indices were measured using a portable spirometer. Regression analysis was applied to construct prediction equations for forced vital capacity (FVC) and other spirometric indices (FEV(1), FEF(50), FEF(25), FEF(25-75)) based on standing height. Predicted spirometric values were compared to values for Caucasians from published studies. In 152 children (ages 5-14 years; 57 girls) lung function increased linearly with height: spirometry index=intercept+[slopexheight], (r(2)=0.68 for FVC and FEV(1) in girls; r(2)=0.78 for FVC and r(2)=0.74 for FEV(1) in boys). Excluding boys-but not girls-in puberty increased fit for FVC (r(2)=0.83) and FEV(1) (r(2)=0.79). Mean predicted values were 5-10% lower than values for Caucasians. In Gypsy children, FVC and expiratory flow function increase linearly with standing height and predicted values are lower than those for Caucasians of similar height.     

Spirometric reference equations for European females and males aged 65-85 yrs.

The aim of this study was to describe spirometric reference equations for healthy never-smoking European adults aged 65-85 yrs and to compare the predicted values of this sample with those from other studies including middle-aged and/or older adults. Reference equations and normal ranges for forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory volume in six seconds (FEV6), FEV1/FVC ratio and FEV1/FEV6 ratio were derived from a healthy subgroup of 458 subjects aged 65-85 yrs. Spirometry examinations followed the 1994 American Thoracic Society recommendations and the quality of the data was continuously monitored and maintained. Reference values and lower limits of normal were derived using a piecewise polynomial model with age and height as predictors. The reference values of FEV1 and FVC from the present study were higher than those given by prediction equations from the European Community for Coal and Steel. By contrast, use of prediction equations from Caucasian-American elderly subjects (Cardiovascular Health Study) consistently overpredicted FVC and FEV1 in females by 8.5 and 2.1%, respectively. In males, equations from the Cardiovascular Health Study overpredicted FVC by 2.8%, whilst underpredicting FEV1 by 2.5%. In conclusion, these results underscore the importance of using prediction equations appropriate to the origin, age and height characteristics of the subjects being studied.     

Spirometric changes in normal children with upper respiratory infections

Recent evidence that certain uncomplicated upper respiratory infections induce pulmonary function abnormalities in adults prompted a prospective study in children, in whom such infections occur more frequently. In a longitudinal study, 55 children 2.5 to 11 years of age were observed for a mean duration of 2 years. Spirometry and lung volume studies were obtained routinely every 3 months, during each upper respiratory infection, and 4 weeks after illnes, providing data for 617 "well" and 237 "illness" observations. After grouping of data by sex and age (less than 84 of greater than 84 months), each spirometric parameter was analyzed using linear regression with individual identification, height, and clinical status (normal versus upper respiratory illness) as independent variables. Adjusted mean values of forced vital capacity, 1-sec forced expiratory volume, peak expiratory flow, maximal mid-expiratory flow, and expiratory flow at 50 per cent of the forced vital capacity all decreased during upper respiratory illness. The data suggest that lower respiratory tract involvement without signs or symptoms of lower airway or alveolar disease occurs with upper respiratory illnesses of varied etiologic origin in childhood.     

Spirometric variability in a longitudinal study of school-age children

OBJECTIVES: To describe spirometric reproducibility in a longitudinal study of students from Mexico City, and also the frequency of subjects fulfilling quality criteria proposed for children. SUBJECTS AND METHODS: Three thousand three hundred forty-seven participants from the third through sixth grades of elementary school were recruited to perform biannual spirometry, yielding a maximum of seven evaluations and a total of 15,563 tests. Standard recommendations of the American Thoracic Society (ATS) were followed, using dry rolling-seal volume spirometers. RESULTS: During their first spirometric test, > 95% of the subjects fulfilled each of the quality criteria proposed by ATS for adults, though not all of them did so simultaneously. For example, only 72.4% obtained three acceptable maneuvers, reproducibility for FEV(1) and FVC to < 200 mL, and a small back-extrapolated volume that increased to 92.3% by the second test. Between phase 1 and phase 7 of the study, spirometry quality increased significantly, as a result of subject and technician training. Intratest and intertest (with a 6-month difference) spirometric variability was less in boys than in girls. Intratest variability was also lower in younger and taller subjects. Technicians contributed significantly to intratest and intertest variability, the latter decreasing if the same technician performed both evaluations. CONCLUSION: Children > 7 years old can fulfill ATS criteria of quality after the first spirometric evaluation. To maintain quality of spirometric tests in longitudinal studies of children, a strict control is required, especially of technician performance.     

Accidental firearm fatalities among New Mexico children

STUDY HYPOTHESIS: Risk factors associated with unintentional gunshot fatalities among children include gender and race of the decedent, type of firearm used, and whether loaded guns are stored within the home. STUDY POPULATION: All New Mexico children 0 to 14 years old unintentionally killed by a firearm between 1984 and 1988. METHODS: The New Mexico Office of the Medical Investigator master mortality file was reviewed retrospectively to identify all unintentional firearm fatalities occurring in New Mexico children during a five-year period. Medical investigator, autopsy, and police reports were analyzed to identify epidemiologic factors associated with these deaths. Chi-square and Fisher's exact tests were used to analyze the data. RESULTS: Twenty-five unintentional firearm fatalities were identified. These deaths occurred most frequently among children playing with loaded firearms found within the home. A disproportionate number involved handguns. CONCLUSIONS: The study results provide a basis for preventive strategies that limit accessibility or decrease lethality of loaded firearms within the home.     

Spirometric reference values for white European children and adolescents: Polgar revisited

We analyzed six spirometric data sets collected in the Netherlands, Austria, the United Kingdom, Spain, and Italy. The objectives were to establish whether (1) it was possible to describe spirometric indices from childhood to adulthood, taking into account the adolescent growth spurt, and (2) there are systematic differences in ventilatory function between children and adolescents in different parts of Western Europe. The study comprised 2,269 girls and 3,592 boys, aged 6–21 years. The range in standing height was 110–185 in girls, 110–205 in boys. The model applicable to all data sets was In FVC or In FEV₁ = a + (b + c · A)· H, where H = standing height and A = age; this model prevents the phase shift between the adolescent growth spurt in length and lung volume from leading to an age-dependent bias in predicted values. There was surprising agreement between most of the data sets; systematic differences are probably due to technical factors arising from ATPS-BTPS corrections and from defining the end of breath with pneumotachometer systems. Taking those into account, prediction equations for FVC, FEV₁, and FEV₁%FVC were developed with “lower limits of normal” which should be applicable to children and adolescents of European descent. It is proposed that the approach of analyzing available data sets should also be applied to other ventilatory indices, data collected in adults and elderly subjects, or in other ethnic groups, and that an international data base be set up to that end. © 1995 Wiley-Liss, Inc.     

New resting energy expenditure prediction equations for patients with rheumatoid arthritis

Objectives. Resting energy expenditure (REE), one of the maincomponents of total energy expenditure, can be measured viaindirect calorimetry and/or predicted from equations. The lattermay be misleading in RA, as they do not take into account themetabolic alterations occurring in RA. The objectives of thisstudy are to evaluate the accuracy of widely used REE-predictiveequations in RA patients against measured REE and to developRA-specific equations. Methods. We assessed REE (via indirect calorimetry and severalpredictive equations), fat-free mass (FFM; via bioelectricalimpedance) and disease activity (CRP) in RA patients and healthycontrols. Data from 60 RA patients (experimental group) wereused to assess the accuracy of existing REE equations and todevelop new equations. The new equations were validated in anindependent cross-validation group of 22 RA patients. Thesetwo groups were merged and two final equations were developed. Results. All equations significantly under-predicted measuredREE (from 15% to 18.2%, all at P < 0.001) in the RA experimentalgroup, but not in the control group. After both equations demonstrateda high validity in the cross-validation group, the new finalREE prediction equations developed from the total RA sample(n = 82) were: Model 1: REE (kcal/day) = 126.1 x FFM^0.638 xCRP^0.045 (R² = 0.70) and Model 2: REE (kcal/day) = 598.8 x weight^0.47x age^–0.29 x CRP^0.066 (R² = 0.62). Conclusion. The new equations provide an accurate predictionof REE in RA patients and could be used for clinical monitoringof resting metabolism of these patients without the requirementfor specialized personnel. KEY WORDS: Resting energy expenditure, Metabolism, Equation, Prediction Submitted 14 May 2007; revised version accepted 10 January 2008.