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PubMed2005

A multi-centre European study of factors affecting the discharge destination of older people admitted to hospital: analysis of in-hospital data from the ACMEplus project.

OBJECTIVES: to examine the relationship between seven predictor variables (recorded on Day 3 of hospital admission) and discharge destination in non-elective medical patients aged 65+ years. DESIGN: prospective cohort. SETTING: eight centres in six European countries. PREDICTOR VARIABLES: age, gender, living alone, physical function (three categories based on Barthel Index), cognition (Katzman's orientation-memory-concentration test), main body system affected (based on International Classification of Diseases), number of geriatric giants (GGs) involved in the referral (a GG being a problem with falling, mobility, continence or cognition). MAIN OUTCOME MEASURES: discharge destination (by Day 90) in three categories: 'HOMESAME' (return to previous residence), 'INSTIN90' (discharge to alternative residence or still in hospital at 90 days), 'DEADINHO' (death in hospital), RESULTS: in 1,626 patients, discharge destination was HOMESAME in 84.7%, DEADINHO in 8.9% and INSTIN90 in 6.4%. Mean duration of stay was 17.7 days, median 12. Univariate analyses showed a statistically significant relationship between all seven predictor variables and discharge destination. Physical function was the best single predictor with a seven-fold difference in adverse outcome rates between the best and worst categories. On multiple logistic regression, significant predictor variables were as follows. (i) For DEADINHO: physical function, cognition, gender; (ii) for INSTIN90: physical function, living alone, GGs, age, gender. Multiple linear regression identified physical function, GGs and living alone as predictors of loge length of stay. CONCLUSION: case-mix systems to compare risk-adjusted hospital outcome in older medical patients need to incorporate information about physical function, cognition and presenting problems in addition to diagnosis.

Activities of Daily Living↗

PubMed2004

Adipocytokines, fat distribution, and insulin resistance in elderly men and women.

BACKGROUND: The aim of this study was to evaluate the relation between adiponectin and leptin, fat distribution, and insulin resistance in elderly men and women. METHODS: 68 elderly participants (28 men and 40 women) aged 66-77 years, with body mass index (BMI) ranging from 19.83 to 37.18 kg/m2, participated in the study. In all participants, we evaluated BMI, waist and hip circumferences, sagittal abdominal diameter (SAD), fat mass (FM) by dual energy X-ray absorptiometry, fasting and 2-hour glucose, insulin, homeostasis model assessment of insulin resistance (HOMA), leptin, and adiponectin. RESULTS: Elderly women had significantly higher circulating levels of adiponectin and leptin compared to men even after adjusting for age, FM, or waist circumference. In men and women, leptin was positively associated, whereas adiponectin was negatively associated, with BMI, indices of body fat distribution, as well as FM and FM%. Both fasting insulin and HOMA showed significant positive correlation with leptin and negative correlation with adiponectin in both sexes. In a step-wise multiple regression model with HOMA as the dependent variable and age, gender, waist circumference, FM, leptin, and adiponectin as independent variables, waist entered the regression first, explaining 19.7% of HOMA variance, leptin was second, and adiponectin was third, explaining each one an additional 10% of variance. In a multiple linear regression analysis, leptin and adiponectin alone explained up to 38% of HOMA variance. CONCLUSION: Leptin and adiponectin together seem to be strictly related to insulin resistance in elderly people, independently of body fat and body fat distribution.

Absorptiometry, Photon↗

PubMed1996

The influence of health-related quality of life and social characteristics on hospital use by patients with AIDS in the Boston Health Study.

OBJECTIVES: The authors examine whether health-related quality of life (HRQL) and social factors were independent predictors of future hospital use for persons with acquired immunodeficiency syndrome (AIDS). METHODS: A panel of 305 patients with AIDS treated at three provider settings in the Boston, Massachusetts area were enrolled during 1990 and 1991. Data were collected at baseline study enrollment and again 4 months later. Patient interviews, hospital bills, and medical charts were used to measure hospital use (admissions and days during the 4 months after enrollment), sociodemographic characteristics (age, gender, race, education, insurance, homelessness, alcohol use, and AIDS risk factors), disease burden (patient severity and a three-level opportunistic diseases and complications score), HRQL (patient-reported symptoms, activities of daily living, neuropsychological status, and global health assessment), system of care, and use of prophylactic drugs. Logistic regression was used to estimate the odds of admission. Total days of hospital care by patients with at least one admission were analyzed using multiple linear regression. Clinical models of hospital use were developed first from the variables measuring disease burden and system of care. Models estimating the associations between hospital use and all other predictor variables measured at baseline then were estimated using stepwise techniques, controlling for variables in the core model. RESULTS: Patients were more likely than their reference groups to be hospitalized if they had serious opportunistic diseases (adjusted odds ratio [OR] = 2.7), had poorer neuropsychological status (OR = 1.9), were non-white (OR = 2.0), or were homeless (OR = 3.3) (all P < or = 0.05). Activities of daily living were associated moderately (OR = 1.3; P = 0.07). Only system of care and neuropsychological status predicted total hospital days. CONCLUSIONS: The results indicate that future hospital use by persons with AIDS may be influenced by social and other health-related factors in addition to the more clinically related characteristics that are recorded in a medical chart. It therefore may be appropriate to assess these factors when considering options for intervention or when comparing patterns of use among patient groups or settings.

Acquired Immunodeficiency Syndrome↗

PubMedDate not supplied

Relationship between fatty liver, alanine aminotransferase, HBsAg and hepatitis C virus.

A community health survey of 923 residents aged 30 years or more was performed in Putai Township of Taiwan. To elucidate the relationships between hepatitis C virus (HCV) and surrogate tests for non-A, non-B hepatitis in hyperendemic areas of hepatitis B virus (HBV) serum levels of alanine aminotransferase (ALT), triglycerides, cholesterol, hepatitis B surface antigen (HBsAg) and antibody to HCV (anti-HCV) were examined. Glucose tolerance tests and the history of diabetes treatment were used to define the diabetes status. Fatty liver was diagnosed by sonography. The prevalence of anti-HCV was 2.6% (95% confidence interval, 1.6-3.6%). Elevated ALT and fatty liver were significantly associated with anti-HCV in univariate analysis. Anti-HCV was not an associated factor for fatty liver after adjusting for serum triglycerides and cholesterol, sex, body mass index and diabetes status through multiple logistic regression. However elevated ALT was still associated with anti-HCV after adjusting for serum triglycerides, sex, body mass index, HBsAg and age through multiple linear regression. The anti-HCV prevalence was similar between HBsAg-positive and negative subjects. Aggregation of HCV infection was found among spouses. It was concluded that elevated ALT and intimate contact with HCV carriers might be associated factors for HCV infection, and that HBV infection and fatty liver were not related to HCV infection in Taiwan.

Adult↗

PubMed2003

Nuchal cord encirclements and birth weight.

OBJECTIVE: To determine if the presence of a single or multiple nuchal cord encirclement has a negative effect on fetal growth. STUDY DESIGN: Data were retrieved from consecutive deliveries at our institution between January 1991 and December 1996. Our computerized database included live-born single and multiple births with a birth weight of > or = 300 g. ANOVA and multiple linear regression were used for statistical analysis. RESULTS: Among the 13,256 deliveries, a single nuchal cord encirclement was observed in 3,250 (24.5%), and multiple encirclements were present in 504 (3.8%). There was no association between the diagnosis of growth restriction and the presence of a cord encirclement. The mean birth weight was no different in the presence of a single or multiple nuchal cord encirclement than with no encirclement (3,206 g or 3.135 g vs. 3,252 g; F = .08, P = .7). After controlling for substance abuse, medical or obstetric complications, race, infant sex, congenital anomalies and gestational age, there was no effect of a single or multiple cord encirclement on mean birth weight. CONCLUSION: Birth weight is unaffected by a single or multiple nuchal cord encirclement.

Adult↗

PubMed1978

RNA synthesis in rat liver cells with different DNA contents.

The DNA content of mature rat liver parenchymal cells falls into three distinct classes with 1:2:4 amounts of DNA. These classes represent 2 N, 4 N, and 8 N cells. We have measured the changing proportions of these cells from 0.75 to 24 months of age. We have obtained a useful approximation for the numbers of each ploidy class, for cellular preparations from liver, as a function of the amount of DNA and age. Multiple linear regression analysis revealed that the average DNA content per cell is given by the relationship DNA/cell = 41.28(1/2)--324.14 Age1/4 + 499.37 Age1/8--207.24, with a multiple correlation coefficient of 0.990. Measurements of the amount of RNA synthesized in a 15-min period revealed that the relative proportions were 1.2:1.0 for 4 N:2 N cells of young rats, 1.3:1.1.:1.0 for 8 N:4 N:2 N cells of intermediate ages, and 1.1:1.0 for 8 N:4 N cells of old rats. The absolute amounts of RNA synthesized by each ploidy class declined with age.

Animals↗

PubMed1992

The determinants of elevated total plasma cholesterol levels in cardiac transplant recipients administered low dose cyclosporine for immunosuppression.

Elevated total plasma cholesterol level is a frequent finding after cardiac transplantation. To identify risk factors for the development of hypercholesterolemic states, we applied multivariate statistics in a logistic and linear manner. Six-month posttransplantation levels of total plasma cholesterol in 57 adult heart recipients were available for analysis. Maintenance immunosuppression was carried out with either cyclosporine and azathioprine or both agents plus low-dose steroids. Total plasma cholesterol levels were dichotomized for the logistic analysis (1) by the age- and sex-matched 75th and 90th percentiles of a reference population according to National Institutes of Health treatment guidelines and (2) by the cut point 250 mg/dl. Twelve potential risk factors were evaluated as covariates: recipient age, body weight after 6 months, body weight gain over 6 months, body mass index after 6 months, body mass index gain over 6 months, current cyclosporine dosage, trough level of cyclosporine in whole blood according to high-performance liquid chromatography after 6 months, cumulative cyclosporine dosage over 6 months, serum bilirubin, type of original cardiac disease, maintenance steroids, and steroid bolus treatment. Multivariate logistic regression yielded the type of original cardiac disease as a significant predictor of posttransplantation hypercholesterolemia exceeding the 90th percentile (p = 0.019) and of hypercholesterolemia exceeding 250 mg/dl (p = 0.032). Maintenance steroids were identified as a second significant cofactor (p = 0.069) for total plasma cholesterol levels exceeding 250 mg/dl. Multiple linear regression again revealed the type of original cardiac disease and maintenance steroids as significant predictors by p values of 0.005 and 0.013, respectively. Patients with coronary artery disease as the original cardiac pathology and low-dose maintenance steroids had the greatest risk for the development of elevated total plasma cholesterol levels after cardiac transplantation. However, the overall predictive quality of the linear model was limited (multiple r value 0.43), which indicates that other variables besides the tested ones attributed to elevated total plasma cholesterol levels. These results confirm the adverse role of maintenance steroids on posttransplantation hypercholesterolemia and demonstrate the type of original cardiac disease as the most important risk factor. They suggest that abnormalities of lipoprotein metabolism and dietary factors continue to affect total plasma cholesterol levels after cardiac transplantation.

Adult↗

PubMed1990

A test of the linear-no threshold theory of radiation carcinogenesis.

It has been pointed out that, while an ecological study cannot determine whether radon causes lung cancer, it can test the validity of a linear-no threshold relationship between them. The linear-no threshold theory predicts a substantial positive correlation between the average radon exposure in various counties and their lung cancer mortality rates. Data on living areas of houses in 411 counties from all parts of the United States exhibit, rather, a substantial negative correlation with the slopes of the lines of regression differing from zero by 10 and 7 standard deviations for males and females, respectively, and from the positive slope predicted by the theory by at least 16 and 12 standard deviations. When the data are segmented into 23 groups of states or into 7 regions of the country, the predominantly negative slopes and correlations persist, applying to 18 of the 23 state groups and 6 of the 7 regions. Five state-sponsored studies are analyzed, and four of these give a strong negative slope (the other gives a weak positive slope, in agreement with our data for that state). A strong negative slope is also obtained in our data on basements in 253 counties. A random selection-no charge study of 39 high and low lung cancer counties (+4 low population states) gives a much stronger negative correlation. When nine potential confounding factors are included in a multiple linear regression analysis, the discrepancy with theory is reduced only to 12 and 8.5 standard deviations for males and females, respectively. When the data are segmented into four groups by population, the multiple regression vs radon level gives a strong negative slope for each of the four groups. Other considerations are introduced to reduce the discrepancy, but it remains very substantial. Since cigarette sales data are available only on a statewide basis, mean radon data for states are analyzed. The linear regression for lung cancer rates vs radon levels is also negative and has a much steeper slope than that for the county data. When cigarette sales per capita is introduced into the regression, the negative slope for dependence on radon level is essentially unchanged.

Environmental Exposure↗

PubMed2001

The association of foster care or kinship care with adolescent sexual behavior and first pregnancy.

OBJECTIVE: Each year more than 500 000 children enter out-of-home placement. Few outcome studies of these children specifically address high-risk sexual behavior and adolescent pregnancy. Our study investigated the relationship between living in kinship or foster care and high-risk reproductive behaviors in a nationally representative sample of women. METHODS: Data from 9620 women ages 15 to 44 years in the 1995 National Survey of Family Growth were analyzed in a cross-sectional study. Three groups-foster (n = 89), kinship (n = 513), and comparison (n = 9018)-were identified on the basis of self-reported childhood living situations. Bivariate and multiple linear regression analyses were performed. The outcome variables were age at first sexual intercourse and at first conception and the number of sexual partners. RESULTS: After adjustment for multiple predictor variables, foster care was associated with younger age at first conception (difference: 11.3 months) and having greater than the median number of sexual partners (odds ratio: 1.7, 1.0-2.8). Kinship care was associated with younger age both at first intercourse (difference = 6 months) and at first conception (difference: 8.6 months) and having greater than the median number of sexual partners (odds ratio: 1.4, 1.1-1.8). There were no differences between the kinship and foster groups. CONCLUSIONS: A history of living in either foster or kinship care is a marker for high-risk sexual behaviors, and the risk is comparable in both out-of-home living arrangements. Recognition of these risks may enable health care providers to intervene with high-risk youth to prevent early initiation of sexual intercourse and early pregnancy.

Adolescent↗

PubMed2006

Functional field score: the effect of using a Goldmann V-4e isopter instead of a Goldmann III-4e isopter.

PURPOSE: To investigate the underestimation of field loss in functional field score (FFS) between the Goldmann isopters III-4e and V-4e in visually impaired patients, in order to develop a predictive model for the FFS(III-4e) based on FFS(v-4e) that adjusts for possible confounders. Although the visual field is generally evaluated using Goldmann isopter III-4e, it has the disadvantage that not all low-vision patients are able to see the stimulus corresponding to this isopter. METHODS: Goldmann visual fields were obtained from 58 patients with a variety of eye diseases. Eligibility criteria were age of 18 years or older and valid results of a Goldmann III-4e and V-4e visual field test in at least one eye. Linear regression was used to develop the model, setting FFS(III-4e) as the dependent variable and FFS(V-4e) as the independent one. RESULTS: The FFS(V-4e) was higher than the FFS(III-4e), the mean difference being 14.56 points (95% CI, 12.48 -16.64). Multiple linear regression analysis showed that age, functional acuity score, primary eye disease, and central-peripheral loss were not confounders for the prediction of FFS(III-4e). FFS(III-4e) was estimated with the following equation: FFS(III-4e) = -19.25 + 1.063 x FFS(V-4e). CONCLUSIONS: The relationship between FFS(III-4e) and FFS(V-4e) is linear, and the FFS(V-4e) can be used to estimate the FFS(III-4e). In practice, just subtracting 19.25 points of the value of FFS(V-4e) will be sufficient to estimate the value of FFS(III-4e). This model should give confidence about using the bigger isopter for determining the visual impairment of a person by the FFS.

Adult↗

PubMed1998

Factors of weight loss in patients with HIV and chronic diarrhea.

Weight loss is significant in patients with HIV and chronic diarrhea. The aim of our study was to test for the links between weight loss, the level of food intake, and the severity of diarrhea and nutrient malabsorption. One hundred and sixteen patients with HIV and chronic diarrhea underwent a standardized gastrointestinal and nutritional evaluation, which included a questionnaire on diarrhea, a prospective estimation of food intake, a measurement of blood parameters and fecal lipid and nitrogen outputs, a stool examination for bacteria and parasites, and upper and lower digestive tract endoscopy. Diarrhea resulted from an infection by Cryptosporidia, Microsporida, or other pathogens in 22%, 20%, and 13% of the patients, respectively. Diarrhea appeared idiopathic in 45% of the patients. A significant negative correlation existed between the severity of weight loss and the levels of nutrient intake (p < .005), and a significant positive correlation between the severity of weight loss and stool frequency (p < .01). Multiple linear regression identified low caloric intake and high stool frequency as predictive of weight loss. No significant correlation was found between weight loss and the parameters of malabsorption, either by bivariate study or multiple regression. These results suggest that, in patients with HIV and chronic diarrhea, the degree of wasting is significantly related to the levels of dietary intake and the clinical severity of diarrhea, but not to the extent of nutrient malabsorption.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

Comparison of ridge regression, partial least-squares, pairwise correlation, forward- and best subset selection methods for prediction of retention indices for aliphatic alcohols.

A quantitative structure-retention relationship (QSRR) study based on multiple linear regression (MLR) was performed for the description and prediction of Kováts retention indices (RI) of alcohol compounds. Alcohols were of saturated, linear or branched types and contained a hydroxyl group on the primary, secondary or tertiary carbon atoms. Constitutive and weighted holistic invariant molecular (WHIM) descriptors were used to represent the structure of alcohols in the MLR models. Before the model building, five variable selection methods were applied to select the most relevant variables from a large set of descriptors, respectively. The selected molecular properties were included into the MLR models. The efficiency of the variable selection methods was also compared. The selection methods were as follows: ridge regression (RR), partial least-squares method (PLS), pair-correlation method (PCM), forward selection (FS) and best subset selection (BSS). The stability and the validity of the MLR models were tested by a cross-validation technique using a leave-n-out technique. Neither RR nor PLS selected variables were able to describe the Kováts retention index properly, and PCM gave reliable results in the description but not for prediction. We built models with good predicting ability using FS and BSS as a selection method. The most relevant variables in the description and prediction of RIs were the mean electrotopological state index, the molecular mass, and WHIM indices characterizing size and shape.

Journal Article↗

PubMed1994

Hematocrit levels in sleep apnea.

This study addresses the hypothesis that patients with obstructive sleep apnea, who exhibit recurrent episodes of oxygen desaturation at night, have higher hematocrit levels than nonapneic control subjects. We prospectively studied 624 patients referred to the sleep disorders center at St. Michael's Hospital because of suspicion of sleep apnea. All patients had nocturnal polysomnography and measurements of hematocrit level, hemoglobin value, WBC count, and platelet count. Smoking history and awake oxygen saturation (SaO2) was recorded in all of them. Nocturnal oxygenation was assessed using three indices: lowest nocturnal SaO2 (LoSaO2), mean nocturnal SaO2 (MnSaO2) and percent of total sleep time spent at SaO2 lower than 85 percent (TST85%). Patients with TST85% in the lowest quartile (TST85% = 0) had minimally lower hematocrit levels than patients with TST85% in the highest quartile (8 < or = TST85% < or = 90): 0.41 +/- 0.03 vs 0.40 +/- 0.02 in female subjects and 0.45 +/- 0.05 vs 0.43 +/- 0.05 in male subjects, respectively (p < 0.05). Multiple linear regression analysis revealed that MnSaO2, age, and pack-years of smoking were significant predictors of hematocrit level, but they accounted for only 9 percent of the variability in hematocrit level (multiple R2 = 0.087; p < 0.05). We conclude that intermittent nocturnal hypoxemia during episodes of apnea does not lead to clinical polycythemia, but is associated with minor elevations in hematocrit value. These small elevations are unlikely to be useful as markers of hypoxic stress associated with sleep apnea.

Adult↗

PubMed2000

Predicting population dental disease experience at a small area level using Census and health service data.

BACKGROUND: Information on the dental disease patterns of child populations is required at a small area level. At present, this can be provided only by expensive whole population surveys. The aim of this study was to evaluate the ability of Census data combined with health service information to provide estimates of population dental disease experience at the small area level. METHOD: Clinical dental data were collected from a large cross-sectional survey of 5-year-old children. A preliminary series of bivariate linear regression analyses were undertaken at ward level with the mean number of decayed, missing or filled teeth per child (dmft) as the dependent variable, and the Census and health service and lifestyle variables suspected of having a strong relationship with dmft as independent variables. This was followed by fitting a multiple linear regression model using a stepwise procedure to include independent variables that explain most of the variability in the dependent variable dmft. RESULTS: All deprivation indicators derived from the Census showed a highly significant (p<0.001) bivariate linear relationship with ward dmft. The Jarman deprivation score gave the highest R2 value (0.45), but the Townsend index (R2=0.43) and the single Census variable 'percentage of households with no car' (R2 = 0.42) gave very similar results. The health and lifestyle indicators also showed highly significant (p<0.001) linear relationships with dmft. The R2 values were generally much lower than the deprivation-related Census variables, with the exception of the percentage of residents who smoked (R2 = 0.42). None of the health or lifestyle variables was included in the final dental disadvantage model. This model explained 51 per cent of the variability of ward dmft. CONCLUSIONS: The results demonstrate the strong relationship between dental decay and deprivation, and all of the commonly used measures of deprivation exhibited a similar performance. For this population of young children health and health services shelf data did not improve on the ability of deprivation-related Census variables to predict population dental caries experience at a small area level.

Child, Preschool↗

PubMed2006

A comparison of multivariable regression models to analyse cost data.

RATIONALE, AIMS AND OBJECTIVES: Analysis of cost data is important in providing reliable information to aid budgeting decisions. Certain features of cost data, such as its typically highly skewed distribution and the need to estimate arithmetic mean costs in order to allow inferences to be made on total costs, make it difficult to analyse. Multivariable regression analysis is useful for estimating the influence of explanatory variables on cost in order to predict costs of future patients and allows for the control of variables which influence cost but whose distributions differ between comparison groups. This is especially important in the case of observational studies, where there may be no control over the balance of characteristics between the comparison groups. METHOD: This paper compares the appropriateness of various multivariable models of cost data by examining regression diagnostics, using as an example data collected on costs incurred in the treatment of inflammatory bowel disease. The models compared are normal and bootstrapped multiple linear regression, median regression, gamma model with the log link and normal linear regression (NLR) of log costs. RESULTS: Gamma modelling with the log link was found to be the most suitable model. CONCLUSIONS: Bootstrapping was found to make very little difference to conclusions from the NLR model.

Health Care Costs↗

PubMed1994

Airway hyperresponsiveness, prevalence of chronic respiratory symptoms, and lung function in workers exposed to irritants.

The association between occupational exposure to airway irritants and the prevalence of chronic respiratory symptoms and level of lung function, and whether these associations were modified by airway hyperresponsiveness, smoking, and a history of allergy were studied in 668 workers from synthetic fibre plants. Respiratory symptoms were recorded with a self administered Dutch version of the British Medical Research Council questionnaire, with additional questions on allergy. Airway responsiveness was measured by a 30 second tidal breathing histamine challenge test. On the basis of job titles and working department, the current state of exposure of all workers was characterised as (1) no exposure, reference group; (2) white collar workers; (3) SO2 HCl, SO4(2); (4) polyester vapour; (5) oil mist and vapour; (6) polyamide and polyester vapour; (7) multiple exposure. Workers exposed to airway irritants were not simultaneously exposed to airborne dust. Airway hyperresponsiveness (AHR), defined as a 20% fall in forced expiratory volume in one second (FEV1) at < or = 32 mg/ml histamine, was present in 23% of the subjects. The association between exposure groups and prevalence of symptoms was estimated by means of multiple logistic regression; the association with level of lung function (forced vital capacity (FVC), FEV1, maximum mid-expiratory flow rate (MMEF)) was estimated by means of multiple linear regression. Both methods allow simultaneous adjustment for potential confounding factors. The exposure groups were associated with a higher prevalence of chronic respiratory symptoms. Lower prevalence of symptoms was found for workers exposed to SO2, HCl, and SO4(2-), most likely due to pre-employment selection procedures. Current smoking, AHR, and a history of allergy were significantly associated with a higher prevalence of chronic respiratory symptoms, independent of each other, and independent of irritant exposure. The association between exposure and prevalence of symptoms was greater in smokers than in ex-smokers and non-smokers. This difference was most clearly seen in the polyester vapour and polyamide and polyester vapour group. No modification of the association between exposure groups and prevalence of symptoms by airway hyperresponsiveness could be shown. The exposure groups were not significantly associated with a lower level of lung function. Adjustment for chronic respiratory symptoms did not change the results. There were no indications of a possible interaction between exposure and AHR, current smoking, or a history of allergy on lung function. Workers of the polyester vapour and the oil mist and vapour group with >10 years of exposure had a lower FEV1 (beta = -295 and -358 ml) and significantly lower MMEF (beta = -1080 and -1247 ml/s; p < 0.05) than the reference group. The number of workers of both group were, however, small (n = 10 and n = 13 respectively). More investigations between low level exposure to irritant and respiratory health.

Adult↗

PubMed1994

Dietary sodium intake and the risk of airway hyperreactivity in a random adult population.

BACKGROUND: High dietary sodium intake has been identified as a potential cause of asthma and airway hyperreactivity. This study was designed to test the hypothesis that dietary sodium intake is an independent determinant of the risk of hyperreactivity in the general population, and to assess the role of atopy in the association between these factors. METHODS: Airway reactivity to methacholine, atopy, 24 hour urinary sodium excretion, and self-reported smoking and symptom history were measured in a random sample of 1702 adults aged 18-70 from an administrative district of Nottingham. Hyperreactivity was defined as a PD20FEV1 of 12.25 mumol or less, and atopy was defined quantitatively as the mean allergen skin weal response to Dermatophagoides pteronyssinus, cat fur, and grass pollen, and categorically as the occurrence of any allergen response 1 mm or greater than the saline control. Multiple logistic regression analysis was used to estimate the independent relative odds of hyperreactivity, atopy, or symptoms in relation to sodium excretion in all 1702 subjects, and multiple linear regression to assess the independent relation between sodium excretion and mean allergen skin weal diameter, and the PD20 value amongst hyperreactive subjects. RESULTS: There was no relation between the relative odds of hyperreactivity to methacholine and 24 hour urinary sodium excretion, either before or after adjustment for age, smoking, allergen skin weal diameter, and sex, and similarly no relation if the analysis was restricted to men or women only. The relative odds of having at least one allergen skin test response 1 mm greater than the saline control were increased in relation to sodium excretion after adjustment for age, sex, and smoking by a ratio of 2.08 (95% CI 1.04 to 4.15) per log10 unit increase in sodium excretion, but there was no evidence of an association between sodium excretion and the occurrence of self-reported wheeze, hay fever, eczema, or asthma. There was no relation between 24 hour sodium excretion and the magnitude of the mean allergen skin weal response or the PD20 value. CONCLUSIONS: These findings do not support the hypothesis that a high dietary sodium intake is a risk factor for airway hyperreactivity or atopic disease in the general adult population.

Adolescent↗

PubMed1989

Correlates of arterial oxygenation during exercise in severe chronic obstructive pulmonary disease.

In the present study, we have undertaken a detailed analysis of the respiratory physiologic correlates of SaO2 during mild constant-load exercise in 38 patients with severe but stable COPD. Several respiratory physiologic variables that would be expected to influence exercise SaO2 were entered into a stepwise multiple linear regression analysis with mean exercise SaO2 as the dependent variable. Two variables (Dco and resting SaO2) were found to correlate strongly with mean exercise SaO2 (multiple r = 0.80; p less than 0.00001) and accounted for 65 percent of the variability among patients. The PaCO2 influenced resting SaO2 but had no independent influence on exercise SaO2. Subsequently, the model of mean exercise SaO2 derived in the present analysis was found to accurately predict mean exercise SaO2 in a group of 19 similar patients (r = 0.85; p less than 0.0001). While these findings do not establish a cause-and-effect relationship, they may provide clinicians with further insight as to which patients are likely to desaturate during exercise.

Aged↗