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Biomedical subjects

Q T Pham

Publications and source records attributed to Q T Pham.

At least 19 recordsLinked to original sources
PubMed1992

Morbidity in retired coke oven plant workers.

The effect of past occupational exposure on morbidity was studied in 354 coke oven workers in Lorraine Collieries (France) who retired between 1963 and 1982, and were still alive in 1988; 96% of them participated in this study. Occupational exposure to respiratory hazards during the working life was retraced for each subject. No significant association between the occupational exposure and the frequency of ischemic cardiopathies, arterial hypertension, gastro-duodenal ulcers, and respiratory symptoms was revealed. However, subjects who had worked on the Ovens, in the Workshops, and in the Byproducts showed a prevalence of arterial hypertension significantly higher than the non- or slightly exposed subjects. The healthy worker effect phenomenon, the exclusion of deceased subjects, and the small size of this retiree population may conceal possible differences between exposure groups.

Age Factors↗
PubMed1992

Iron miners--a ten year follow-up.

1167 workers of Lorraine (France) iron mines, a random sample of 5600 workers aged 35 to 55 years, at work in 1975 constituted the initial cohort that was examined twice at 5-year intervals after the first examination. A questionnaire on respiratory symptoms and smoking habits (MRC questionnaire) plus questions on the work history of each participant was completed, vital capacity (VC), forced expiratory volume in one second (FEV1.0), residual volume (RV) and fractional uptake of CO (FuCO) were measured at the first examination and repeated five and ten years later. At the end of the ten year follow-up, 522 subjects were re-examined, 186 were lost to follow-up, 328 answered a mail questionnaire, and 111 had died. The total number of deaths was not different from that of the general population, but for lung cancer the standardized mortality ratio (SMR) was significantly increased (SMR = 3.7). For the miners re-examined, frequency of bronchitis and decrease of functional tests were more related to age and smoking habits than to occupation.

Adult↗
PubMed1992

Lung function in retired coke oven plant workers.

Lung function was studied in 354 coke oven plant workers in the Lorraine collieries (Houillères du Bassin de Lorraine, France) who retired between 1963 and 1982 and were still alive on 1 January 1988. A spirometric examination was performed on 68.4% of them in the occupational health service. Occupational exposure to respiratory hazards throughout their career was retraced for each subject. No adverse effect of occupational exposure on ventilatory function was found. Ventilatory function was, however negatively linked with smoking and with the presence of a respiratory symptom or discrete abnormalities visible on pulmonary x ray films. The functional values were mostly slightly lower than predicted values and the most reduced index was the mean expiratory flow, FEF25-75%. The decrease in forced expiratory volume in one second (FEV1) was often parallel to that in forced vital capacity (FVC), but it was more pronounced for subjects who had worked underground, for smokers of more than 30 pack-years, and for subjects having a respiratory symptom. Pulmonary function indices were probably overestimated because of the exclusion of deceased subjects and the bias of the participants.

Aged↗
PubMed1991

Pertussis in French adolescents: risk factors and respiratory sequels.

An analysis of the risk factors for pertussis and the possible respiratory sequels was carried out in a sample of 499 children and adolescents aged 10-16 years from the general population in north-eastern France. 44 subjects (8.8%) had pertussis during childhood; and the sex ratio was 1 in these cases. Pertussis was significantly associated with a maternal history of respiratory disease, residence in a rural area and coal heating. In a multiple logistic regression model, a maternal history of respiratory disease was the only significant factor (p = 0.01), the number of siblings being of borderline significance (p = 0.06). No increase in respiratory symptoms or asthma prevalence was found in our subjects who had pertussis during childhood.

Adolescent↗
PubMed1991

[Skin sensitivity to respiratory allergens in agricultural workers and wage-earners].

Prick tests were performed with "pneumallergerns" (mites, cereal dusts, animal dander, pollens, moulds--totalling 35 allergens) among 742 agricultural workers of the Meuse department (North East of France) as part of an epidemiological study on respiratory and immuno-allergological problems. Among those with positive skin tests, 47.9% had positive skin tests for mites, 22.4% for cereal dusts, 10.7% for animals, 12.7% for pollens and 7.8% for moulds. Polysensitization was frequent (19.5% of the population). When the skin test was positive for main house dust mites it frequently was positive for storage mites, too. Among vegetal dusts sensitization, soy bean allergy yielded the highest frequency (6.5%). As for animal sensitization, cow dander was the most frequently observed positive test. Sensitization to pollens and moulds was comparatively rare. This study shows the large frequency and diversity of "latent allergy" to pneumallergens among agricultural workers.

Agriculture↗
PubMed1991

Prospective mortality study among iron miners.

A prospective mortality study was conducted over a period of 5 years on a group of 13,801 iron miners, who were alive on January 1, 1982. During this 5-year period, 1813 deaths were registered. For 1222 (67.4%), the cause of death and work history are known. For 135 (7.4%), the cause of death is known, but not the work history. For 455 (25.1%), the cause of death is unknown. Proportional mortality ratio (PMR) is significantly higher than 1 for lung cancer (PMR = 2.51, p less than 0.001) and for stomach cancer (PMR = 2.31, p less than 0.001). The results are discussed in regard to occupational risks that result in these two kinds of increased mortality rates, and the hypothesis of redox activity on the surface of dust particles is advanced as a common denominator.

Adult↗
PubMed1990

Determinants of alveolar nitrogen slope and closing volumes in healthy adolescents.

The alveolar nitrogen slope (PIII), closing volume (CV), and closing capacity (CC) were measured by the single-breath nitrogen washout method (SBN2) in a group of 187 healthy children and adolescents (92 boys, 95 girls), 10 to 16 yr old, from the general population of Lorraine, France. The test was performed using a computerized system, which also made the calculations. About one out of five healthy subjects in this population were unable to satisfactorily perform the test; the failure rate was the same for the two sexes (20% in boys, 21.5% in girls) and significantly higher in younger children (26.6 and 14.5% for children under and over the age of 13, respectively; p = 0.03). The distribution of results was skewed for PIII and practically normal for log PIII, CV, VC, and CV/VC or CC/TLC ratios. PIII was highly significantly, inversely related to anthropometric variables; the highest coefficient was that for the age-weight interaction term in boys (= r -0.57 for PIII, -0.62 for log PIII) and for weight in girls (r = -0.57 for both PIII and log PIII). Because the anthropometric variables were strongly interrelated (r between 0.45 and 0.79), multiple regressions did not materially improve the prediction of PIII. In simple regression, weight alone explained 36% of the variability of log PIII in boys and 32% in girls. The mean PIII was significantly higher in girls as compared to boys (1.14 +/- 0.38 versus 0.98 +/- 0.17% N2/L, p = 0.02); CV and CC in milliliters were related to body build as other lung volumes; the CV/VC in girls and CC/TLC ratio in both sexes were not related to anthropometric variables. In boys, CV/VC decreased significantly with height (p = 0.035 for CV/VC versus height3).

Adolescent↗
PubMed1989

Arc welders' respiratory health evolution over five years.

The respiratory health of 138 arc welders and 106 control subjects in the same company was studied in 1981 and in 1986. Most of the subjects welded mild steel using the Metal Inert Gas (MIG) process. The controls were workers in the same company, not exposed to any known pulmonary risk. The welders and controls in the analysis had not changed their professional activity nor their smoking habits during these five years. The examinations consisted of a questionnaire on respiratory symptoms, a thoracic auscultation, a chest X-ray and lung function tests: flow-volume curve and steady state CO transfer test. The examinations in 1986 confirmed the risk of non specific radiological impairment (pulmonary reticulo-micronodulation) and of obstruction in the small bronchi, which had already been observed in 1981 in the arc welders in this company. These impairments did not seem to have evolved more than in the controls, but do however justify regular surveillance of the respiratory health of arc welders.

Adult↗
PubMed1989

Respiratory hazards in hard metal workers: a cross sectional study.

A cross sectional study was conducted on 513 employees at three hard metal plants: 425 exposed workers (351 men, 74 women) and 88 controls (69 men, 19 women). Cough and sputum were more frequent in workers engaged in "soft powder" and presintering workshops compared with controls (12.5% and 16.5% v 3.5%). Spirometric abnormalities were more frequent among women in sintering and finishing workshops compared with control women (56.8% v 23.8%) and abnormalities of carbon monoxide test were more frequent in exposed groups than in controls; this difference was more pronounced in women (31.4% v 5.6%) than in men (18.5% v 13%). No significant correlation was observed between duration of exposure and age adjusted lung function tests. Slight abnormalities of chest radiographs (0/1, 1/1 according to ILO classification) were more frequent in exposed men than controls (12.8% v 1.9%) and mostly in soft powder workers. In subjects with abnormal chest radiographs FVC, FEV1 and carbon monoxide indices (fractional uptake of CO or CO transfer index or both) were lower compared with those with normal chest radiographs. Although relatively mild, the clinical, radiological, and functional abnormalities uncovered call for a regular supervision of workers exposed to hard metal dust.

Adult↗
PubMed1989

[Respiratory health of children and atmospheric pollution. I. Respiratory symptoms].

The impact on the respiratory system of complex industrial pollution (dust, sulphur dioxide, nitrogen oxides, hydrocarbons) was assessed by an analytical epidemiological study in a population of school children in the northeast of France. The parents of 375 children aged from 9-12 (middle school course 1 and 2) from the polluted zone and 523 children of the same age in a neighboring zone which was not polluted have filled in standardised questionnaires (respiratory symptoms, previous infections and allergies, frequency of infection in infancy; tobacco habits, professional and educational attainments of the parents, domestic environment). In the exposed children the majority of respiratory symptoms were more frequent (e.g., respiratory sounds in the boys, 15.6% against 7.9% p less than 0.01) and the absenteeism from school was more numerous (66.9% against 59.1% p less than 0.01). However, the interpretation of the results had to take into account the existence of confusing factors: parental smoking habits and the use of coal fires increased the prevalence of symptoms in the polluted zone, whereas a less crowded population worked in the inverse direction; likewise the educational level of the parents was higher in the polluted zone. After adjusting for these confusing factors, the frequency of rhinitis and absenteeism from school was significantly higher in exposed children.

Air Pollution↗
PubMed1989

[Respiratory health of children and atmospheric pollution. II. Ventilatory function].

Respiratory function (forced vital capacity-FVC; forced expired volume in one second-FEV1; maximal mid-expiratory flow-DEMM; peak flow-DP; maximal expiratory flow at 75-50-25% of vital capacity CV-DEMx) was studied in children of comparable age, sex and height (9 to 12 years) in a polluted zone (the exposed group n = 223) and a neighboring non-polluted zone (the control group n = 211) in the north of Lorraine. There was no significant difference in ventilatory function between the two groups. Amongst other factors capable of influencing the ventilatory function in the children we found an influence of parental smoking habits (particularly the mothers) identifiable in the non-exposed zone, above all in boys. A sub-segment analysis identified that in the absence of parental smoking, there was a negative influence of open coal fires. The discordance between the results of the measures of respiratory function and the prevalence of different respiratory symptoms, of acute infections and absenteeism from school, is probably explained by the interference of other factors which were not controlled in this study (e.g., ethnic factors and physical activity) and by the moderate level of the pollution; an over-reporting of respiratory symptoms by parents in the exposed zone could not be excluded.

Air Pollution↗
PubMed1989

[The respiratory health of children and industrial and domestic air pollution].

At the request of its inhabitants, an epidemiological survey was conducted among the children of Carling, a particularly polluted industrialized town in the department of the Moselle in North-East France. Contrary to all expectations, no major toxic effect of industrial pollution on the respiratory health of the children was found. There was some correlation between the fact of living in a polluted area and a claimed respiratory morbidity. However, the potentially harmful effect of atmospheric pollution could not be translated in terms of abnormalities of respiratory function. In contrast, a significant effect of the smoking habits of the parents, and particularly of the mothers, on respiratory symptoms and spirographic data of their children was observed.

Air Pollution↗
PubMed1989

Lung function in adolescents after uncomplicated whooping cough in childhood.

Ventilatory function (forced vital capacity, forced expiratory volume in one second, forced expiratory flows), static lung volumes, phase III slope and closing volume (single-breath nitrogen washout test) were measured in 499 children and adolescents aged 10-16 yrs from a general population sample in North-East France. A history of whooping cough was given by 44 children (22 of each sex); their results were compared to those of the 455 children (215 girls) with a negative history. The only difference between the two groups was a minimal increase in the residual volume/total lung capacity ratio in cases (19.2 +/- 3.1 vs 18.0 +/- 2.9%). We conclude that uncomplicated whooping cough in early childhood did not lead to significant pulmonary function abnormality in this population of children born after 1967.

Adolescent↗
PubMed1988

Pulmonary function following mild respiratory tract infections ("common cold") in teenagers.

Ventilatory function--forced vital capacity (VC)--forced expiratory volume (in 1-sec forced expiratory flows) static lung volumes, closing volume, and phase III slope (single-breath N2 test) were compared in 94 children with and 436 children without a history of recent mild acute respiratory infection. Their age ranged from 10 to 16 years; subjects with symptoms on the day of the study were excluded. We found no difference in lung function between the two groups, with the exception of a slight (inconsistently significant) increase in closing volume (CV) and the CV/VC ratio. Although the influence of a persistent increase in interstitial lung pressure leading to early small airways closure cannot be ruled out, this isolated functional abnormality probably represents a spurious positive result, arising by chance when a large number of statistical tests are done.

Acute Disease↗
PubMed1988

Respiratory symptoms and pulmonary function in 871 miners according to Pi phenotype: a longitudinal study.

Pi phenotype was determined and alpha 1 protease inhibitor (alpha 1 Pi) was measured in 871 iron-ore miners examined twice at five years interval. A questionnaire on respiratory symptoms was administered and lung function tests: spirometry (VC, FEV1.0), measurements of the residual volume (RV/TLC) and of the CO diffusion (FuCO), were carried out by the same medical and technical team, using the same apparatus. There were no differences in age, length of employment or smoking habits among the three Pi Phenotype groups: M (90.03%), MS (7.1%), MZ (2.8%). The prevalence of clinical symptoms at the initial survey and the incidence of symptoms between the 2 surveys were not related to Pi Phenotype groups. However a significantly steeper decline of FEV1.0/VC was observed in the alpha 1 Pi partially deficient groups MS and MZ (-3.9%) compared with the non-deficient group (-1.8%). No significant difference was observed for VC, RV/TLC and FuCO. This finding suggests that an intermediate deficiency of alpha 1 Pi may be related to a slight but statistically significant impairment of a lung function in occupational conditions.

Adult↗
PubMed1988

Respiratory symptoms or signs on the day of the study alter pulmonary function in teenagers.

Pulmonary function variables (forced expiratory flows and vital capacity, static lung volume, alveolar N2 slope, closing volume and closing capacity) were compared in a group of 10-16 year old children with (n = 65) and without (n = 440) symptoms or signs of mild acute respiratory infection ('common cold'). Symptomatic children had a significant impairment of forced expiratory vital capacity and flows, with no change in static volumes, alveolar N2 slopes and closing volumes. The effect was present only in boys (in whom RV/TLC and phase III slope were borderline abnormal), was more evident in older children (13 to 16 years) and was independent of the smoking habits or the presence of chronic respiratory symptoms. The results are in favour of a predominant involvement of upper airways, but signs of lower airways dysfunction are present in boys and in children 13 to 16 years old.

Acute Disease↗