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The aim of the study was to evaluate the prevalence, the covariates and determinants of respiratory pauses during sleep in a sample of French middle-aged males. Study subjects were 850 active males, aged 22-66 years; 88.4% of them answered the question on breathing pauses during sleep from a structured, validated sleep questionnaire. Forty-one (=5.4%) subjects reported breathing pauses at least once a week; these "positive responders" were older, heavier and had larger neck- and waist girths as compared to subjects with negative answers. Loud habitual snoring, various sleep disturbances, excessive daytime sleepiness, a doctor diagnosis of sleep apnoea, history of stroke and hypertension were significantly more frequent among subjects with breathing pauses during sleep. The prevalence found in this survey was close to that reported from the UK (5.2%). However, by logistic regression, we identified novel determinants of breathing pauses i.e. habitual snoring, loud snoring, and excessive sleepiness, factors well known in clinical setting, but never previously reported in epidemiologic studies.

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In patients with obstructive sleep apnoea (OSA) anatomic and functional upper airway abnormalities are frequent and severe. Invasive methods are used to identify and quantitate the obstruction, to precisely locate its site, etc. as part of pre-treatment or of preoperative evaluations.These methods (lateral skull radiographs, computerized tomography, MRI, fibroscopies, etc) are too expensive and too invasive to be utilized in field surveys. To the classical sleep questionnaires and anthropometric measurements, some simple nose-throat examinations, easily accepted by the volunteers in a population study, could add useful information for the identification of the subjects at risk for sleep-disordered breathing. The present paper is a review of these examinations and of their utility.

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BACKGROUND: The value of flow-volume curves alterations for screening for sleep apnoea is controversial in adults. OBJECTIVE: The purpose of the present study was to assess the possible value of flow-volume curves, in snoring pre-school children to detect upper airway abnormal dynamics. METHODS: We analysed ventilatory function of 190 children aged 5 to 6 years from nine kindergartens in Nancy, France, according to the presence or absence of snoring as declared by their parents. RESULTS: More than half (103 = 54%) of the children never snored; 26 (= 13.7%) snored only with colds, 42 (22.1%) snored occasionally, and 19 (= 10%) snored habitually. The "saw tooth" sign described in adults by Sanders et al in 1981 was absent in all the children in this study, and the height-adjusted forced expiratory volume in one second (FEV1/m2) was similar across the four groups. The height-adjusted peak expiratory flow (PEF/m2) decreased uniformly (but insignificantly) from the group of non-snorer (2.11 +/- 0.381/s/m2) through the group of children snoring with colds. (2.05 +/- 0.37) to the group of children snoring occasionally (1.99 +/- 0.33); no significant decrease was found in the group of habitual snorers (2.06 +/- 0.36). CONCLUSION: In this group of young children, we were unable to find the alteration of the expiratory flow-volume loop described in part of the studies in adults. We cannot, however, exclude an alteration of the inspiratory arm of the loop, as this was not recorded by us. Our results, suggesting a reduction in peak expiratory flow with increase in frequency of snoring need to be validated in a larger population of children.

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There is only limited information on the factors associated with nonspecific bronchial hyperresponsiveness (BHR) in farmers. Our purpose was to examine the relationship between BHR and respiratory symptoms, atopy, and abnormalities of lung function in a sample of French farmers. Farmers scheduled for a preventive medicine check-up in northeastern France were examined. Occupational exposure, respiratory symptoms, and work-related symptoms were assessed by questionnaire, sensitization to 34 common and agricultural allergens by skin prick tests, and BHR by the single-dose (1,200 microg) acetylcholine (ACh) challenge test. Data were obtained from 741 farmers (95% of those invited). Seventy-seven subjects (10.3%) had BHR defined as a fall in forced expiratory volume in 1 s (FEV1) >/= 10% after the inhalation of ACh or, for those with a poor lung function, an increase in FEV1 > 10% and > 200 ml after the inhalation of 200 microg of salbutamol. The proportion of asthmalike symptoms, especially wheeze during work, positive skin tests to acarian (storage mites) and cereal dust allergens, and low levels of lung function was significantly greater among reactors than among nonreactors. Stepwise logistic regression analysis showed a significant and independent association between BHR and wheezing during work (OR = 4.99; 95% CI = 2.29-10.89; p = 0.0001) and baseline FEV1 (OR = 1.49; 95% CI = 1.05-2.20; p = 0.026). In conclusion, hyperreactive farmers had significantly more asthmalike symptoms, positive skin tests, and abnormal lung function than normoreactive farmers. Work-related wheeze and low baseline FEV1 were significantly and independently associated with BHR.

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STUDY OBJECTIVES: To verify that sick building symptoms are present in north-eastern France office workers; to try to identify new confounding factors. METHODS: The design was that of a cross-sectional study with control group. We studied with the same methods the personnel of an air-conditioned building (n=425), and of a naturally ventilated building (n=351). Air temperature and humidity, bacterial and fungal densities were measured by the same technical staff in the two buildings. A standard questionnaire on irritative and respiratory symptoms, personal and family history, and lifestyle was completed by the participants. RESULTS: In univariate analysis, exposure to air-conditioning was associated with an increased prevalence of symptoms (odds ratios-OR-between 1.54 and 2.84). A significant increase in sickness absence was also found among subjects working in air-conditioned offices. As a series of factors were suspected to interfere with these associations, logistic regression was applied. This method confirmed exposure to be an independent determinant of 7 symptoms, and also identified two determinants not previously described: a family history of respiratory diseases and "do-it-yourself' activities. IN CONCLUSION: we found the sick building symptoms to be present in a group of French office workers exposed to air-conditioning. We confirmed the influence of a number of confounding factors and described two further confounders - do-it-yourself activities at home and a history of familial respiratory disease.

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Comparative manual and computer measurements of the alveolar N2 slope and closing volumes have indicated systematic differences. When a computerized system is used in field surveys, predicted values are to be obtained under the same conditions. Therefore, we measured the alveolar nitrogen slope (phase III, PIII), closing volume (CV), and closing capacity (CC) from single-breath N2 washout maneuvers in 158 healthy subjects (68 females), ages 21 to 64 years, from a rural community living in a nonpolluted area of northeast France. PIII, the CV to vital capacity ratio (CV:VC, %), and the CC to the total lung capacity ratio (CC:TLC, %) were regressed against age, height, weight, and the body mass index (BMI, kg/m2) and prediction equations with 95% confidence intervals were computed. PIII increased with age in both sexes and tended to decrease with height in males (r = -0.19, p = .08). The CV:VC and CC:TLC ratios depended on age and, in males, increased with the BMI. Despite accepting a 15% difference between the test VC and the spirometric VC, only 46.3% of asymptomatic nonsmokers produced a valid single-breath nitrogen washout (SBN2) test. This high failure rate limits the usefulness of the test for epidemiologic purposes when older populations "naive" to pulmonary function testing are studied under field-survey conditions.

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Within-subject (difference between paired tests, or coefficient of variation [c. var.] of three consecutive measurements) and between-subjects (standard deviation of the mean group) variability were assessed for the variables derived from the single-breath nitrogen (SBN2) test in a group of healthy, asymptomatic subjects (n = 289) aged 20-64 years, from a rural area in North-East France. Duplicate measurements in 99 subjects showed excellent agreement between the two attempts (correlation coefficients between 0.94 and 0.98) for static lung volumes and the alveolar N2 slope (PIII); closing volumes (CV) were more variable (r = 0.77 for absolute value, 0.79 for % VC) while closing capacities (CC) were in intermediate position (r = 0.86 for absolute value, and 0.88 for % TLC). The variability of three consecutive measures in 190 subjects showed the coefficients of variation to be low for static volumes and closing capacity (2.4-7.4%) and higher for PIII (15.1%) and CV or CV/VC (18.2 and 17.8%). The analysis of variance did not detect significant differences between the three sets of measurements, with the exception of a progressive increase of vital capacity (VC), and decrease in residual volume (RV) from test 1 to test 3, the total lung capacity being the same. Variability was uninfluenced by age or sex, except a higher c. var. for female VC as compared to males (2.8 vs. 2.2%, P = 0.02) and a higher variability of TLC (2.9 vs. 2.3%, P = 0.03) and VC (2.8 vs. 1.9%, P = 0.003) in people older than 40 years as opposed to those younger than 40 years.

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The prevalence of habitual snoring and its associations with respiratory symptoms, personal and familial risk factors, ear, nose, and throat (ENT) abnormalities, and its influence on ventilatory function were studied in a sample of 190 children aged 5 to 6 years from nine kindergartens in Nancy (northeastern France). Nineteen (10%; 95% CI 5.7-14.3%) of the children were habitual snorers; the prevalence was the same in boys and girls. In univariate analysis habitual snoring was significantly associated with a personal history of exercise-induced bronchospasm [relative risk (RR) 4.50]; a history of adenotonsillectomy (RR, 2.56); a personal history of allergy (RR, 2.83); a sibling history of atopy (RR, 2.39); and doctor-assessed tonsillar hypertrophy (RR, 2.51). These factors were entered into a logistic regression model that retained as independent determinants exercise-induced asthma, personal history of allergy, sibling history of allergy, and tonsillar hypertrophy. The height-adjusted peak expiratory flow rate was slightly, non-significantly lower in habitual snorers as compared to non-snorers (2.01 +/- 0.32 vs 2.10 +/- 0.38 L/s/m2). Due to the limited numbers in the sample, the increased risk for paternal (RR, 1.8) and maternal (RR, 1.6) smoking at home remained nonsignificant.

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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.

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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).

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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.

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'Conventional' (lung volumes, airway conductance, CO transfer factor) and 'small-airway dysfunction' (single-breath N2 washout, maximal expiratory flows with air and a helium-oxygen mixture) tests were performed in a group of asymptomatic male ex-smokers (n = 20) with normal spirometry and compared to those of a similar group of middle-aged nonsmokers (n = 41). The study group had a mean life-long consumption of 13.2 +/- (SD) 8.8 pack-years and had stopped smoking 1-21 years ago, mean 7.3 +/- (SD) 5.8 years. Among the conventional tests, a minimal increase in residual volume and residual volume/total lung capacity ratio was found. Ex-smokers had a steeper phase III slope, a higher closing volume/vital capacity ratio, lower forced flows with air and a higher volume of isoflow, but neither difference between the group means was significant. There was a trend to more abnormal small-airway tests as a function of increased smoking, but only the correlation between percent of predicted closing volume and pack-years reached significance (r = +0.51, p less than 0.05). We conclude that small-airway function normalizes in the long term in most ex-smokers if they become asymptomatic, with less than 10% still having abnormal results years after they stopped smoking.

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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.

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The variability, short-term (1 hour) and long-term (2 weeks) reproducibility of the variables derived from the single-breath N2 test were evaluated in a group of 56 healthy children aged 10 to 16 years with a computerized system. The variability was low for vital capacity and total lung capacity (coefficient of variation less than 3%), moderate for residual volume and phase III N2 slope (9 and 13%) and very high for closing volume (more than 50%). A closing volume could not be identified by the computer algorithm in 18.3% of the trials. The reproducibility of the variables was satisfactory both at 1 hour and at 2 weeks, with the exception of the closing volume, whose increase at 2 weeks seemed to be due to methodological factors. We conclude that reliable results of static lung volumes and phase III N2 slope, but not of closing volume, may be obtained in children by a computerized system in epidemiological studies.

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