Biomedical subjects

A Forcina

Publications and source records attributed to A Forcina.

5 recordsLinked to original sources

PubMed2001

Analysis of capture-recapture data with a Rasch-type model allowing for conditional dependence and multidimensionality.

In this article, we show that, if subjects are assumed to be homogeneous within a finite set of latent classes, the basic restrictions of the Rasch model (conditional independence and unidimensionality) can be relaxed in a flexible way by simply adding appropriate columns to a basic design matrix. When discrete covariates are available so that subjects may be classified into strata, we show how a joint modeling approach can achieve greater parsimony. Parameter estimates may be obtained by maximizing the conditional likelihood (given the total number of captures) with a combined use of the EM and Fisher scoring algorithms. We also discuss a technique for obtaining confidence intervals for the size of the population under study based on the profile likelihood.

Algorithms↗

PubMed1999

Dyspnoea is associated with pulmonary function impairment in exposed workers.

This study aimed to evaluate the prevalence of dysponea and its predictors in studies on several working male groups in British Columbia (BC), Canada (cedar sawmill, grain elevator, pulpmill, and aluminum smelter workers), and Tuscany (T), Italy, (shoe and furniture makers, millers, bakers, and pharmaceutical workers). We performed cross-sectional health studies (interviews and pulmonary function tests) for 2498 BC and 1474 T workers exposed to air contaminants, and 1110 BC and 243 T controls. Similar questionnaires and the same definitions were used in BC and in T. Pulmonary function tests were also performed. The participation rates were >92% in BC workers and 82% in T workers. The overall prevalence of moderate dyspnoea was not different in exposed BC and T workers in comparison with controls. Slight dyspnoea was significantly more frequent in BC workers, but not in T workers, with respect to controls. After adjusting for age, body mass index (BMI), smoking, current asthma, and chronic bronchitis, forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were found to be significantly associated with slight and moderate dyspnoea in BC workers, and slight dyspnoea in T workers. Isolated dyspnoea is associated with reduction in FEV1 and FVC in working populations, after adjusting for potentially confounding variables.

Adult↗

PubMed1992

Modelling balanced longitudinal data: maximum likelihood estimation and analysis of variance.

For linear models, assuming a within-experimental-units covariance structure that incorporates errors of measurement, serial correlation, and variation between units, results on explicit estimation of regression parameters are used to simplify maximum likelihood estimation of covariance parameters. The use of an analysis of variance table as a simpler alternative to likelihood inference is illustrated with two examples.

Analysis of Variance↗

PubMed1988

An 11-year longitudinal study of the occupational dust exposure and lung function of polyvinyl chloride, cement and asbestos cement factory workers.

Standardized questionnaires and lung function tests were administered in 1973, 1980, and 1984 to 126 workers occupationally exposed to polyvinyl chloride (PVC) dust, to cement dust, or to asbestos cement dust until 1974-1978 and to PVC thereafter. The workers in the last group were assigned to two asbestos exposure categories (heavy and slight). The decline in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1.0) was analyzed with regard to the length of time since the data of first employment. After adjustment for age, height, and smoking status at the date of first employment, the decline in FVC and FEV1.0 among the nonsmokers-light smokers was slightly accelerated with length of employment in the PVC and slight asbestos exposure groups and markedly accelerated with time since first employment in the heavy asbestos exposure group. The heavy smokers in all the exposure groups had FVC and FEV1.0 predicted values that were lower than those of the nonsmokers-light smokers; these differences remained constant with length of employment. Cessation of asbestos exposure for about 10 years did not seem to change lung function decline.

Adult↗

PubMedDate not supplied

Monitoring of peak expiratory flow rates during occupational asthma treatment.

The purpose of this study was to evaluate the effect of anti-inflammatory drug treatment on respiratory symptoms and lung function in twelve subjects with occupational asthma while at work. PEFR was monitored for four weeks and antiasthmatic drugs (salbutamol, chromolyn sodium and beclomethasone dipropionate) were administered for three weeks, starting after the first week of PEFR monitoring, in an unchanged working environment. After treatment five subjects became asymptomatic, six improved and one continued to have unchanged work-related asthmatic symptoms. There were only minor increases in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and mean forced expiratory flow during the middle half of FVC (FEF25-75). Bronchial reactivity was studied in eleven subjects: six worsened and five improved. PEFR at 0600 h increased by 9.4% in nine responders and decreased by 5.8% in three non-responders. After treatment diurnal variation (DV) in PEFR decreased by 28.4% in responders and 30.8% in non-responders, even if at the fourth week it was 1.75 higher in non-responders compared to responders. In conclusion, in this study a continuous treatment of occupational asthma with anti-inflammatory drugs minimized respiratory symptoms, slightly increased PEFR and greatly reduced DV in PEFR.

Adult↗