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At least 1,477 records · Page 82Linked to original sources

PubMed2004

Fibroblast growth factor (FGF)-23 in patients with primary hyperparathyroidism.

OBJECTIVE: We aimed to determine the serum level of fibroblast growth factor-23 (FGF-23) in patients with primary hyperparathyroidism (pHPT) to understand its physiological role in the disorder. PATIENTS AND METHODS: Ninety-eight patients with pHPT who underwent parathyroidectomy formed the study group. We also measured serum FGF-23 in 11 of these patients on postoperative day 6. RESULTS: Serum FGF-23 levels was significantly higher in pHPT patients than in healthy controls (35.6+/-17.8 ng/l vs 28.9+/-11.2 ng/l (mean+/-s.d.); P<0.001 (Pearson's correlation coefficient)), but there was no significant difference in the serum FGF-23 level between pHPT patients with normal renal function (creatinine clearance (Ccr) of >or=70 ml/min) and healthy controls. Serum FGF-23 correlated positively with serum calcium (P<0.0001) and intact parathyroid hormone (PTH) (P<0.01), and negatively with Ccr (P<0.001), serum phosphate (P<0.05), and serum 1,25-dihydroxyvitamin D (1,25(OH)(2)D) (P<0.05). Multiple linear regression analysis of factors potentially determining serum FGF-23 levels in pHPT patients showed serum calcium (P<0.01) and Ccr (P<0.001) to be significant predictors. The serum levels of FGF-23 did not change after parathyroidectomy despite the normalization of serum calcium values. Multiple linear regression analysis revealed that serum FGF-23 was not a significant predictor of serum phosphate or 1,25(OH)(2)D in pHPT patients. CONCLUSIONS: FGF-23 may not play a significant role in regulating phosphate or 1,25(OH)(2)D in pHPT patients, especially in those with normal renal function. Further studies are warranted to determine the role of FGF-23 in renal insufficiency or failure.

Adult↗

PubMedDate not supplied

Predictability of the size of laser-induced lesions in T1-Weighted MR images obtained during interstitial laser-induced thermotherapy of benign prostatic hyperplasia.

The purpose of this study was to predict diameters of lesions induced by laser-induced thermotherapy (LITT) of benign prostatic hyperplasia (BPH) from MRI signal/tissue temperature correlations during on-line monitoring with a temperature-sensitive fast low-angle shot (FLASH) sequence. Twenty LITT procedures with Nd:YAG (1,064 nm) and diode (830 nm) lasers were monitored on line with a T1-weighted FLASH sequence at 1.5 Tesla. Interstitial prostate temperature (T) was measured on line in 10 LITT procedures and laser energy deposition in 12. Slopes of linear regression curves for signal intensity (SI) over T were applied to determine SI at 60 degrees C to estimate diameters of intraprostatic LITT lesions. Diameters of unperfused LITT lesion cores in contrast-enhanced T1-weighted images served as gold standards. Linear regression curves with an average slope of -.54% SI/degrees C were obtained in 17 LITT procedures. Correlation coefficients were r = .92-.95 for SI/T and SI/energy deposition. Baseline variation of SI at body temperature was +/-3.9%, corresponding to +/-7 degrees C. Prediction of size (13 lesions) from on-line FLASH imaging was correct in 10 of 13, whereas 3 lesions were overestimated. Prediction of LITT lesion diameters from on-line MRI monitoring is possible with a temperature-sensitive FLASH sequence in the prostate. Accuracy may suffice to assign target regions of interest to tissue locations to be protected from coagulation.

Aged↗

PubMed1985

Dynamics of disinfection of selected preservatives against Escherichia coli.

Mathematical models were determined relating preservative concentration and D values (decimal reduction times at 25 degrees C; pH 6.9-7.1) against Escherichia coli in aqueous medium. Preservatives investigated were 2-bromo-2-nitro-1,3-propanediol (Bronopol), N-(hydroxymethyl)-N-(1,3-dihydroxymethyl-2, 5-dioxo-4-imidazolidinyl)-N'-(hydroxymethyl)urea (Germall II), phenethyl alcohol, and benzyl alcohol. Linear regression was used to determine D values [i.e., the time required for a particular concentration of preservative at a specified pH, temperature, and medium to cause a 90% reduction of viable organisms (E. coli)] from a number of concentrations of each preservative. Linear regression of the log D values versus the log of the concentration (a minimum of 4 concentrations per preservative) were used to derive power curves. Concentration exponents, eta values (the logarithmic values relating changes in rates of kill for specified changes in concentrations) and A values (extrapolated D values at 1% concentration), were determined. Correlation coefficients for these power fits ranged from -0.987 to -0.999. Plots depicting the closeness of fit of the models to the actual data are shown.

Culture Media↗

PubMed1995

Using simulation data to predict lung geometry for inhomogeneity corrections in breast cancer treatments.

PURPOSE: To develop a statistical model based only on simulation measurement data, to predict the lung geometry in the central slice of the tangential radiation treatment fields for breast cancer. METHODS AND MATERIALS: A linear regression analysis was performed on 22 patients to determine the shape of lung in the central axis plane of the tangential radiation fields. Data collected include the greatest perpendicular distance (GPD) measured from the chest wall to the field border on computed tomography (CT) images, the central lung distance (CLD) measured from the posterior field border to the chest wall on the simulation portal images, and the lung contours digitized at 1 cm intervals. The lung contours of these patients were fitted to a parabolic curve through a polynomial regression model. A lung template based on the regression model is used to construct a "generic lung" contour on patients' external body contours for treatment planning. The accuracy of this technique was tested on another group of 15 patients for its ability to predict the shape of lung on the central axis plane and the accuracy of dose to the prescription point. RESULTS: The polynomial regression indicates that all the patients' lung contours in the tangential fields follow a parabolic curve: Y = -0.0808 X2 + 0.0096 X + 0.0326. The maximum lung involvement (GPD) can be determined from the value of CLD measured on the simulation film by the linear regression model with a determination coefficient of 0.712. The 15-patient test results indicate that our model predicts the lung separation on the central axis with an average deviation of 1.35 cm, and the average absolute dose deviation to the dose prescription point is 1.46%. CONCLUSION: The model presented in this article provides an efficient method to estimate the lung geometry for breast cancer treatment planning without the requirement of CT data. The lung contour predicted by our model is useful for calculating dose distributions with inhomogeneity correction and may potentially benefit patients at higher risk of pulmonary toxicity.

Breast Neoplasms↗

PubMed2004

Evaluation of an improved blood-conserving POCT sampling system.

OBJECTIVE: To evaluate a modified point-of-care (POCT) testing i-STAT analyzing cartridge that connects directly to the sampling port of a blood-conserving sampling line. DESIGN AND METHODS: In an in vitro setup, blood samples were drawn from a blood-conserving sampling line connected to a miniature cardiopulmonary bypass (CPB) system. Blood collection from the sampling port was either performed with a syringe necessitating subsequent sample loading on a standard i-STAT cartridge (conventional procedure) or with a modified i-STAT sampling cartridge allowing blood flow from the sampling port directly into the cartridge (modified procedure). The loaded cartridges were subsequently inserted into the i-STAT Portable Clinical Analyzer for sample analysis. Multiple parameters such as blood gases, electrolytes, hematocrit, and glucose were measured. A series of 30 paired measurements was performed. Corresponding series of values were compared using linear regression analysis and Bland-Altman bias analysis (P < 0.05). RESULTS: Twenty-five complete measurement series consisting of 12 parameters (pH, pCO(2), pO(2), SO(2), base excess, bicarbonate concentration, sodium, potassium, ionized calcium, hemoglobin concentration, hematocrit, glucose) were evaluated. Linear regression analysis between the two sampling methods tested demonstrated an excellent correlation for all parameters (Pearson correlation coefficients: 0.859-0.999). Bias and precision between corresponding series showed clinically acceptable performance levels for all parameters. CONCLUSIONS: The modified i-STAT sampling cartridge allows reliable diagnostic blood sampling directly from a blood-conserving sampling line. The technique presented is also applicable to other POCT systems, thus reducing diagnostic blood loss because of the minimal amount of blood required for analysis.

Blood Chemical Analysis↗

PubMed2001

Correlation analyses on binding behavior of heavy metals with sediment matrices.

This article presents the amounts of heavy metals bound to the sediment matrices (carbonates, Fe-oxides, Mn-oxides, and organic matter), the correlations between any two heavy-metal binding fractions, and the correlations between sediment matrices and their heavy-metal binding fractions. Data consisted of 313 sets obtained from five main rivers (located in southern Taiwan) were analyzed by statistical methods. Among six heavy metals analyzed (Zn, Cu. Pb, Ni, Cr, and Co), the statistical results show that Zn is primarily bound to organic matter, and Cr is primarily bound to Fe-oxides. Principal component analysis (PCA) and correlation analysis (CA) result in significant correlations between carbonates bound Ni and carbonates bound Cr, Fe-oxides bound Ni and Fe-oxides bound Cr, and Mn-oxides bound Cu and Mn-oxides bound Cr. From linear regression results, the levels of the six heavy metals bound to either organic matter or Fe-oxides is moderately dependent on the contents of organic matter or Fe-oxides, especially true for Cr and Pb. According to slope values of linear regression, Cu and Cr have the highest specific binding amounts (SBA) to organic matter and Fe-oxides, respectively. A significant correlation between organic matter and organically bound heavy metals implied that organic matter contained in the sediments of the Potzu river and the Yenshui river can be adequately used as a normalizing agent. However, the six heavy metals bound to either carbonates or Mn-oxides do not correlate with carbonates or Mn-oxides. The obtained results also imply that competitions of various sediment phases in association with heavy metals occur, and organic matter and Fe-oxides are more accessible to heavy metals than other sediment phases.

Binding Sites↗

PubMedDate not supplied

Implementing the Fisher's discriminant ratio in a k-means clustering algorithm for feature selection and data set trimming.

The Fisher's discriminant ratio has been used as a class separability criterion and implemented in a k-means clustering algorithm for performing simultaneous feature selection and data set trimming on a set of 221 HIV-1 protease inhibitors. The total number of molecular descriptors computed for each inhibitor is 43, and they are scaled to lie between 1 and 0 before being subjected to the feature selection process. Since the purpose is to select some of the most class sensitive descriptors, several feature evaluation indices such as the Shannon entropy, the linear regression of selected descriptors on the pKi of selected inhibitors, and a stepwise variable selection program are used to filter them. While the Shannon entropy provides the information content for each descriptor computed, more class sensitive descriptors are searched by both the linear regression and stepwise variable selection procedures. The inhibitors are divided into several different numbers of classes. They are subsequently divided into five classes due to the fact that the best feature selection result is obtained by the division. Most of the good features selected are the topological descriptors, and they are correlated well with the pKi values. The outliers or the inhibitors with less class-sensitive descriptor values computed for each selected descriptor are identified and gathered by the k-means clustering algorithm. These are the trimmed inhibitors, while the remaining ones are retained or selected. We find that 44% or 98 inhibitors can be retained when the number of good descriptors selected for clustering is three. The descriptor values of these selected inhibitors are far more class sensitive than the original ones as evidenced by substantial increasing in statistical significance when they are subjected to both the SYBYL CoMFA PLS and Cerius2 PLS regression analyses.

Journal Article↗

PubMed1986

On the choice of mathematical models for the estimation of lethal gene equivalents in man.

A range of mathematical models and error distributions was used to examine the validity of linear regression methods for the calculation of lethal gene equivalents. Because of the restricted span of inbreeding coefficient F values available in human studies and the limited number of data points, equivalent results were obtained with all combinations tested. It was concluded that linear regressions should be employed only for the detection of significant inbreeding effects in man and that their application to the estimation of lethal gene equivalents was not warranted.

Female↗

PubMed1999

[Topics in clinical dentistry. Trends in the Dutch dental literature].

Aim of the study was to evaluate a method for selecting topics suitable for developing dental clinical practice guidelines in the Netherlands, based on an analysis of Dutch dental journals. A search for dental clinical topics was conducted by analysing Dutch dental journals, magazines and series over the period 1992-1997. The numbers of publications per topic were plotted against the publication years. The number of publications as well as the value of the slope of the linear regression were considered to be indicators of the importance of a topic. 'Dental implants (indication)' had the highest number of publications, followed by 'orthodontic treatment planning' and 'periodontology (indication)'. The topic 'practice hygiene' showed the highest value of the slope of the linear regression, followed by 'TMJ dysfunction' and 'dental implants (indication)'. With this method, it is feasible to detect changes and tendencies in the Dutch dental literature. It permits a selection of clinically relevant topics over a time span. It was concluded that this method may be very useful in the selection of a topic, but should probably be combined with other methods.

Dental Implants↗

PubMed1987

Accuracy of blood pressure measurement by the Dinamap monitor in infants and children.

Indirect BPs measured by the Dinamap monitor, an oscillometric device, and the conventional auscultatory method were compared with the direct radial artery pressure in infants and children. There were 29 patients in the Dinamap group with a median age of 18 months (ranges 1 month to 16 years) and 20 patients in the auscultatory group with a median age of 3.5 years (ranges 3 months to 16 years). The direct radial artery pressures were recorded on a strip chart and the ranges of pressures were obtained for systolic, diastolic, and mean pressures. The range of the direct readings was converted to a weighted single reading, and comparisons were made between the direct and indirect readings. The linear regression equation between the direct (x) and the Dinamap (y) readings (with correlation coefficient) was y = 1.05x - 5.36 (r = .97) for systolic, y = 1.10x - 4.65 (r = .903) for diastolic, and y = 1.06x - 4.21 (r = .917) for mean pressures. The linear regression equation (with correlation coefficient) for the auscultatory pressure was y = 1.60x - 68.23 (r = .872) and y = 1.38x - 16.47 (r = .874) for diastolic pressures. The error was defined as the indirect reading minus the direct reading. The mean error +/- SD was -0.24 +/- 3.26 for systolic, 1.28 +/- 4.74 for diastolic, and 0.10 +/- 4.56 mm Hg for mean pressures by the Dinamap method. It was -1.65 +/- 6.68 for systolic, and 8.70 +/- 5.97 for diastolic pressures by the auscultatory method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1998

Prevalence of an elevated resting energy expenditure in patients with chronic obstructive pulmonary disease in relation to body composition and lung function.

OBJECTIVE: This study describes the prevalence and characteristics of an elevated resting energy expenditure (REE) in patients with chronic obstructive pulmonary disease (COPD). DESIGN AND SETTING: Patients were consecutively admitted to an in-patient pulmonary rehabilitation centre. SUBJECTS: The study group consisted of 172 (123 males) clinically stable patients with COPD, age mean (s.d.) 64(10) y). INTERVENTIONS: REE was assessed by indirect calorimetry (ventilated hood) and adjusted for the influence of fat-free mass (FFM; measured by bioelectrical impedance analysis) using the linear regression equations of REE on FFM generated in 92 healthy age-matched subjects (58 males, age 67(8) y) for men and women separately. The predicted REE adjusted for FFM (REEFFM) was obtained by using the FFM of each individual patient in the linear regression equation of REE on FFM generated in the healthy control group. RESULTS: 26% of the patients were hypermetabolic (defined as REE > 110% REEFFM), characterized by a lower age (60 (10) vs 65 (9) y) and a lower total lung capacity (TLC; 122(27)vs 139(28) %pred) compared to normometabolic patients (P < 0.001). The prevalence of FFM-depletion was equal among normo- and hypermetabolic patients: 36% vs 33% respectively. Depleted patients expressed however a significantly higher residual volume/TLC ratio and a lower maximal inspiratory mouth pressure independently of hypermetabolism (P < 0.05). In contrast, on base of the Harris & Benedict (HB) prediction equations, which do not take body composition into account, 54% of the patients were hypermetabolic (REE > 110% REEHB), characterized by a higher age and a lower body mass and FFM (P < 0.05). CONCLUSIONS: Hypermetabolism commonly occurs in COPD, characterized by less hyperinflation at rest, in contrast to the suggested contribution of an elevated oxygen cost of breathing (OCB) to hypermetabolism in COPD. The higher hyperinflation at rest in FFM-depleted patients independently of hypermetabolism suggests a higher OCB during activities, contributing to the elevated total daily energy expenditure previously reported in COPD. The HB-equations overestimate the prevalence of hypermetabolism and link hypermetabolism incorrectly to aging and depletion.

Aged↗

PubMed1977

Circadian rhythm analysis when output is collected at intervals.

It has long been recognized that many physiological and biochemical parameters show a repeating pattern of variation over 24 hours, i.e., a circadian rhythm. Halberg, Tong and Johnson (1965) used the sinusoidal model with 24-hour cycle to describe this variation. Tong (1976) described the polar coordinate transformation by which the sinusoidal regression problem can be treated as a linear regression problem. When the output of a system following diurnal variation, e.g. the human kidney, is collected at regular intervals and assayed, the expected quantity of substance present corresponds to the integral of the underlying output function. This paper shows that the polar coordinate transformation also linearizes this regression problem. More importantly, the covariance structure of Halberg et al. does not include interindividual variation. An alternative and more general model is proposed here based upon Rao's (1959) growth curve analyses. The latter method allows testing for adequacy of the sinusoidal model and leads to inferences about population parameters. An example is given.

Circadian Rhythm↗

PubMed2004

The Bambui health and aging study: is calibration of dietary intake necessary among older adults?

Accurate measurements of food intake in surveys are difficult to be obtained especially in the older adults. Calibration, using two instruments, has been adopted in order to improve the information. This study was carried out in a random sample of older adults (> or =60) living in a Brazilian town. Food intake was obtained by the semi-quantitative food frequency questionnaire associated with photos (SFFQ-P) and the 24 hours recall (R24) with or without food models. Statistical analysis included tests to compare averages, Pearson's correlation coefficient and multiple linear regression. For all nutrients, the average intake obtained through SFFQ-P was significantly higher compared to the obtained by the R24 (p < or =0.05). SFFQ-P correlated better with R24 with food models, which was chosen as the reference method. In the multiple linear regression, vitamin C, fatty acid, protein and zinc intakes were influenced by age, especially when such nutrients were more concentrated in food not frequently reported. For protein and zinc, the significantly interaction between age with the 24 hours recall may have happened because of a differential selection of food sources as a function of age. This fact is probable related to chewing difficulties, reduction in the income and, a diet simplification associated with less complicated preparations, such as meat. This study reinforces the need for calibration of SFFQ in nutritional surveys among older adults, especially in etiological studies where the exposure assessment has to be accurate. In this case, R24 with food models should be used as a reference method to best estimate the true intake.

Adult↗

PubMedDate not supplied

Intrapartum screen for diabetes in patients without prenatal care: use of labor admission serum glucose.

OBJECTIVE: For patients presenting in labor with no prenatal care, a rapid screening test for gestational diabetes would potentially aid in decisions for tocolysis (e.g., preterm patients) and mode of delivery (e.g., large for gestational age). We sought to determine whether a labor admission serum glucose is of predictive value in the diagnosis of gestational diabetes. METHODS: We obtained labor admission glucose values for laboring patients and compared these with 1-h (50-g) postglucola (1 degree PG) screens obtained at 24 to 32 weeks' gestation. Diabetics being treated with insulin were excluded from the study. Labor admission serum glucose values were compared to 1 degrees PG values by linear regression. Sensitivity and specificity of admission glucose for identification of a positive 1 degree PG (140 mg/dl) were evaluated by a receiver operator curve (ROC). RESULTS: A total of 98 patients with both 1 degree PG screens and labor admission glucose were identified. Linear regression showed no significant correlation of labor admission glucose and 1 degree PG values (r = 0.13; P = 0.9). The ROC failed to demonstrate an optimal admission random glucose cutoff value for diagnosis of diabetes. CONCLUSIONS: In laboring patients without insulin-requiring diabetes, labor admission glucose does not predict an abnormal 1 degree PG and thus does not aid in labor management of patients with suboptimal prenatal care.

Adult↗

PubMed1994

Relation between QT intervals and heart rates from 40 to 120 beats/min in rest electrocardiograms of men and a simple method to adjust QT interval values.

OBJECTIVES: The aim of this study was to establish the relation between QT intervals and a wide range of rest heart rates in men. These data provided the basis of a simple method for adjusting the QT interval for heart rate. BACKGROUND: Earlier correction equations give conflicting results, especially at low and high heart rates. METHODS: The QT intervals were measured in 324 electrocardiograms of healthy young men. The sample was weighted for low and high heart rates. A curve relating QT intervals and heart rates from 40 to 120 beats/min was constructed. The QT interval at 60 beats/min was used as the reference value, and an adjusting nomogram for different heart rates was created. The reliabilities of the nomogram and three earlier QT correction equations were tested in the study group and in 396 middle-aged men. RESULTS: The nomogram method presented (QTNc = QT + correcting number) adjusted the QT interval most accurately over the whole range of heart rates on the basis of smallest mean-squared residual values between measured and predicted QT intervals. The Fridericia formula (QTFc = QT/RR1/3) gave the best correction at low, but failed at high, heart rates. The linear regression equation (QTLc = QT + 0.154[1 - RR], Framingham Study) was reliable at normal, but failed at low and high, heart rates. The Bazett formula (QTc = QT/RR1/2) performed poorest at all heart rates. The relation between QT and RR intervals was determined by three linear regressions expressing the slopes 0.116 for heart rates < 60 beats/min, 0.156 for heart rates from 60 to 100 beats/min and 0.384 for heart rates > 100 beats/min. CONCLUSIONS: The QT-RR relation over a wide range of heart rates does not permit the use of one simple adjustment equation. A nomogram providing, for every heart rate, the number of milliseconds that the QT interval must be corrected gives excellent adjustment.

Adolescent↗

PubMed1997

ESR dosimetry of irradiated ascorbic acid.

PURPOSE: As an alternative to heat and gas exposure sterilization, ionizing radiation is gaining interest as a sterilization process for medicinal products. The aim of this work was to develop equations to describe the ESR curves versus dose and storage time after gamma irradiation of ascorbic acid. Several ESR data sets previously acquired in this laboratory were adopted to check the performance of the models. RESULTS: Limit of detection and limit of discrimination are respectively 0.5 kGy and 2 kGy for ascorbic acid. Linear regression is applicable for doses lower than 25 kGy. Since the radiation dose selected must always be based upon the bioburden of the products and the Degree of Sterility required (ANSI/AAMI/ISO 11137), doses in the range 5-25 kGy could be investigated and linear regression would appear to be the least expensive route to follow and gives good results. Quadratic fit, power function, exponential function and bi-exponential functions are of more general applicability to predict irradiation dose. Decay kinetics for radicals versus storage were considered. Nonhomogeneous kinetics with time-dependent rate (diffusion-controlled second-order reaction) and bi-exponential function appeared valid to reproduce the experimental data. Discrimination between irradiated and unirradiated ascorbic acid is possible after a storage of 800 days. CONCLUSIONS: It is worth noting that, at present, ESR is the only technique which proves to be suitable for identification and quantification purposes in irradiated pharmaceuticals. Moreover, other features such as sensitivity, precision, ease and non-destructive readout make ESR superior to other proposed analytical techniques.

Ascorbic Acid↗

PubMed1998

Bioavailability of tryptophan in soybean meal and tryptophan retention in the carcasses of four-week-old ducks.

The objectives of the experiment were to determine the bioavailability of tryptophan in soybean meal for 4-wk-old ducks using the slope-ratio bioassay with L-tryptophan as the reference diet and estimate the efficiency of dietary tryptophan retention in the carcasses of 4- to 7-wk-old ducks. An initial representative group of 12 ducks with an average body weight of 1,951 g (SD = 69) were killed for carcass compositional analysis. A basal diet formulated to contain 1.13 g of tryptophan/kg and adequate in all other amino acids, was supplemented with 0.2, 0.4, or 0.6 g tryptophan/kg from L-tryptophan, or 0.2 or 0.4 g tryptophan/kg from soybean meal. Four pens of three 4-wk-old ducks received each of the six diets for 21 d. Ducks fed the basal diet and the basal diet supplemented with 0.2 or 0.4 g of L-tryptophan/kg for 21 d were used as the final slaughter groups for carcass compositional analysis. Dietary supplemental tryptophan from either L-tryptophan or soybean meal linearly increased final weight (P < 0.05), weight gain (P < 0.10), and gain:feed ratio (P < 0.05). Common-intercept, multiple linear regressions in slope-ratio methodology performed using weight gain and gain:feed ratio as dependent variables and grams of supplemental tryptophan/kg of diet as the independent variable gave 94 and 92% tryptophan bioavailability in soybean meal relative to L-tryptophan, respectively. Linear regression of tryptophan deposition in the carcass on tryptophan intake resulted in a 21% efficiency of carcass tryptophan retention above maintenance.

Animal Feed↗

PubMed1990

Relation between respiratory symptoms, type of farming, and lung function disorders in farmers.

Respiratory symptoms and function were examined in a random sample of 181 farmers (124 pig farmers and 57 dairy farmers) with a mean age of 43 years. Wheezing and shortness of breath during work in the animal house were significantly associated with pig farming (odds ratio 11.4), current smoking (odds ratio 2.2), bronchial hyperreactivity (odds ratio 3.8), and low FEV1 (odds ratio 3.4). Pig farmers had a slightly lower FEV1 than dairy farmers (101% versus 104% predicted, NS). Symptomatic farmers had significantly lower FEV1 than symptomless farmers (93% versus 106% predicted). A multiple linear regression analysis of the cross sectional values of FEV1 showed that there was a decline in FEV1 associated with pig farming (-12 ml/year of pig farming) and smoking (-23 ml/pack year) in addition to the age related decline of 32 ml/year. A multiple linear regression analysis of PC20 histamine showed that bronchial reactivity increased with age, number of pack years, and number of years in pig farming. Work in closed pig rearing units is a pulmonary health hazard and causes decline in lung function.

Adult↗