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Biomedical subjects

R Liard

Publications and source records attributed to R Liard.

16 recordsLinked to original sources
PubMed1992

Peak expiratory flow variability and bronchial responsiveness to methacholine. An epidemiologic study in 117 workers.

We studied the relationships between peak expiratory flow (PEF) variability and bronchial responsiveness to methacholine in 117 workers attending the annual compulsory examination (mean age, 38.7 yr +/- 9.5; men, 86.3%). Subjects recorded their highest PEF out of three, every 3 waking hours (i.e., five times a day) for 7 days, each using a newly purchased Vitalograph peak flow meter, and underwent methacholine challenge tests with a maximal cumulative dose of 1,200 micrograms. Those with a FEV1 fall of 15% or more were considered as reactors. The variability of PEF was expressed as the amplitude percent mean, calculated from daily amplitude (highest-lowest reading/mean reading of the day x 100), averaged over 6 days, from the second to the seventh. This index had a continuous distribution, skewed towards the greatest amplitudes, and correlated negatively with FEV1 (r = -0.25, p = 0.01). Subjects with asthma (n = 8) had greater variations. In the 109 nonasthmatics, greater variability was observed in subjects with wheeze apart from colds, breathlessness, or hay fever; the average amplitude was greater in reactors than in nonreactors to methacholine (16.9% versus 9.3%, p less than 0.001). The subjects with excessive PEF variability were all methacholine reactors, but they were only a subgroup of the reactors. These results provide evidence that excessive PEF variability is an indicator of bronchial hyperresponsiveness to methacholine in a population sample.

Adult↗
PubMed1992

Frequency and correlates of the saw-tooth pattern of flow-volume curves in an epidemiological survey.

The object of this report was to assess the possibility of identifying saw-tooth patterns on flow-volume curves in men aged 28 to 58 years. We studied the frequency of these patterns and their relationships with two indirect signs of UAO increase in FEV1/PEF and FEF50%/FIF50% ratios--as well as with clinical and functional data. Twenty-six of the 360 subjects surveyed, ie, 7.2 percent, had flow oscillations in the inspiratory and/or expiratory part of flow-volume curves, corresponding to the definition of the saw-tooth pattern. We observed significant relationships between the saw-tooth pattern and the mean FEV1/PEF ratio. In 97 subjects, the proportion of those with saw-tooth patterns was 13.4 percent, and the mean FEF50%/FIF50% ratio was 1.53 in those with the pattern vs 1.07 in those without it. These results show that the saw-tooth pattern was not rare in these men.

Adult↗
PubMed1992

[Biological and clinical prevalence of pollinosis caused by ragweeds of the upper valley of the Rhône corridor].

An epidemiological study of ragweed allergy was conducted on 646 employees belonging to 6 factories located in the Rhone valley south of the city of Lyon. Information on seasonal evocative clinical symptoms was obtained through a self-administered questionnaire. Biological prevalence was assessed by measuring anti-ragweed IgE specific antibodies. Measurements were performed by immunoenzymatic assay (W1 Phadezym RAST from Pharmacia). 34 (5,4%) subjects had evocative symptoms whereas 37 (5,9%) had increased specific IgE. Persons with the highest IgE levels were symptomatic. Concordance between symptoms and biology was 35% (12/34). Results indicate that sensitization level varies according to the location of the factory and people's residence, the risk to become allergic being of 10% in the most exposed population. This data emphasize the need to promote anti-ragweed eradication policy.

Adult↗
PubMed1990

Respiratory history during infancy and childhood, and respiratory conditions in adulthood.

The aim of this paper was to study respiratory disorders in infancy and childhood as a risk factor for respiratory conditions in adulthood. During the first part of the survey 15,247 adolescents in the Bordeaux area (average age: 16.5 years, boys = 46.6%) filled in a self-administered questionnaire concerning their respiratory history during infancy and childhood, their present symptoms and their smoking habits. Each subject with chronic cough (n = 538) was then matched with two controls (n = 1094) and the parents of these subjects and of their controls were sent a complementary questionnaire. During the second part, 1807 adults (average age: 39.3 years; men = 49.7%) working at Bordeaux University filled in a self-administered questionnaire about their present respiratory symptoms, smoking habits and respiratory symptoms during adolescence. Spirometry was performed in 172 adolescents and 1665 adults. The results of the first part showed a very significant relationship in adolescents between respiratory history during infancy and childhood and current chronic cough even in non-smokers, non-wheezers and non-asthmatics. The second part showed a very significant relationship in adults between respiratory symptoms during adolescence and present respiratory symptoms on the one hand, and a lower pulmonary function on the other, taking wheezing, smoking and asthma into account. In common with many similar studies, we conclude that respiratory disorders in young children may predispose to later disease, and that consequently it might be important to determine appropriate measures to prevent respiratory illness in childhood.

Adolescent↗
PubMed1989

[Smoking in adolescents in Guadeloupe].

A study was made of the smoking habits of 10,349 teenagers attending secondary school in Grande-Terre, Lamentin and Marie-Galante in Guadeloupe (41.4% were male; mean age 16.4 +/- 1.8). The study was made using a self administered questionnaire which also included questions on respiratory symptoms in teenagers and the smoking habits of their parents. The proportion of regular smokers (greater than one cigarette per day) was 9.2% in boys and 5.6% in girls: the boys were smoking on average 7.3 cigarettes a day, the girls 5.9. The proportion of smokers increased with age, being the highest in the children of managerial and commercial classes or skilled artisans, and was strongly linked to the smoking habits of the parents. Respiratory symptoms were more common in teenagers who smoked.

Adolescent↗
PubMed1988

Prevalence of asthma among teenagers attending school in Tahiti.

The prevalence of asthma was studied in 6731 adolescents (average age 13.5 years, 48.6% boys) attending school in three towns of the isle of Tahiti, according to the ethnic origin of both parents. The pupils completed a self-administered questionnaire in class; 14.3% gave an affirmative answer to the question "Have you ever had attacks of asthma?" (cumulative prevalence). That prevalence was 11.4% in the Europeans, 13.7% in the Chinese, 13.8% in the Polynesians, 15.3% in those whose parents were "halves" (half-bred from Polynesians and Europeans), and 16.0% in the miscellaneous group (= other origins) (P less than 0.02). Asthma was significantly more frequent in boys only among the Europeans and those with one European parent. The results of this study confirm the high prevalence of asthma in French Polynesia found in a previous study. They give no evidence of a racial difference in prevalence but suggest an influence of environment.

Adolescent↗
PubMed1988

Spirometry and maximal expiratory flow-volume curve reference standards for Polynesian, European, and Chinese teenagers.

Lung function was compared and reference standards were determined in 1,007 Polynesian, European, and Chinese teenagers attending school in Tahiti (517 boys, 490 girls; mean age, 14.4 years). Spirometric study results and maximal expiratory flow-volume curves were measured using techniques recommended by the American Thoracic Society. Age, standing height, and weight were chosen as the independent variables for males, and age and standing height for females. Regression equations constructed with logarithmically transformed dependent variables provided accurate predictions. We observed significant racial differences: in the Europeans, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were higher than the mean values predicted for the whole study population, while forced expiratory flow during the middle half of the FVC (FEF25-75%) and maximal expiratory flows after 25, 50, and 75 percent of FVC had been exhaled (V max 25, 50, and 75, respectively) were about equal to the mean values; in the Polynesians, volumes and flows were mostly lower than the mean; in the Chinese, FVC in boys and girls, and FEV1 in girls only, were lower, while the other flows were higher. The FEV1/FVC, FEF25-75%/FVC, Vmax25/FVC, Vmax50/FVC, and Vmax75/FVC were significantly higher than the mean in the Chinese boys and girls and often lower in the Europeans.

Adolescent↗
PubMed1987

Prevalence of asthma in adolescents in various parts of France and its relationship to respiratory allergic manifestations.

Six studies have been carried out in France and French Polynesia to investigate the prevalence of asthma in adolescents attending secondary school and in Paris university students (68,179 subjects overall). All the studies used the same questionnaire, self-administered in the classroom, and interviews administered to students during the university's preventive medicine examination. An epidemiologic definition of asthma was considered an affirmative answer to the question, "Have you ever had attacks of asthma?" The prevalence of asthma ranged from 4 to 12 percent, most often higher in boys with a tendency to increase with age. The relationship between asthma and other allergic respiratory conditions was studied. Some recommendations are made here to improve the validity of data and to increase knowledge about the etiology of asthma.

Adolescent↗
PubMed1986

[Antitubercular therapeutic regimens routinely prescribed in Bas-Rhin and results of treatment].

The overall plans and therapeutic regimens prescribed for new cases of pulmonary tuberculosis notified in the Bas-Rhin in 1979 to 1980 (372 Subjects) were studied, as were relapses occurring over a three year period from the date of notification. As in the preceding analysis of cases between 1970/78, the proportion of patients treated exclusively at home was low (22.8%) and the duration of stay in a Sanatorium was lengthy (mean 86.6 days for cases without bacteriological confirmation and 142.3 days for bacteriologically positive cases). The mean duration of chemotherapy was 12.5 months (+/- 3.7). The therapeutic regimens prescribed showed a significant variability: if 80.6% of patients received, at one time or another, the combination of Isoniazid (H), Rifampicin (R) and Ethambutol (E), only 33.9% of the adults treated received the HRE/HR regimen, for periods of variable duration. Four relapses were seen during the fixed follow-up period.

Adolescent↗
PubMed1985

Common cold with cough on the day of examination: a factor that should be taken into account in epidemiological studies on pulmonary function.

Epidemiologists using pulmonary function tests agree that a number of factors have to be taken into account. In a study carried out among 912 men aged 22 to 54 we found that those having a common cold and cough on the day of examination had lower pulmonary function values. So we suggest that these symptoms should also be considered as a potential confounding factor.

Adult↗
PubMed1979

[Respiratory symptoms in school-age children, in 7 areas of France].

A study of respiratory symptoms in 6918 schoolchildren aged 6-10 years was carried out in 1975, in 7 French areas having different pollution levels. The proportion of children with respiratory symptoms (cough and/or wheezing), dyspnoea, colds and colds "going to the chest" was higher in Paris than in the other areas. The frequency was related to age, allergy and some socio-economic factors. After adjustment for these factors the difference in the respiratory symptoms between those in Paris and elsewhere was still statistically significant. According to 1974 average pollution data, air was more polluted in Paris than in the other areas, particularly for black smoke.

Child↗
PubMedDate not supplied

Analysis of the methacholine dose-response curve: usefulness of a simplified log-logistic model in epidemiological studies.

The object of the study was to find a model to summarize all the information from dose-response curves, by determining the coefficients to be used to compare groups of subjects. Three coefficients were calculated from the following model: F(d)/F(o) = ONE - k(d-delta)alpha+, where F(d)/F(o) was the ratio between FEV1 at dose (d) of methacholine and prechallenge FEV1, 'k' the slope of the relative variation of FEV1 with the dose, 'delta' the threshold dose and 'alpha' a shape factor. The model was applied to the study of hyperresponsiveness in a population of 317 men. The results illustrated the interest of this model which was applicable to 91% of the population and permitted fine discrimination of the groups studied.

Adult↗