[Tobacco consumption of students ages 8 to 22 in Abidjan, 2002]. / Tabagisme des élèves et étudiants âgés de 8 à 22 ans à Abidjan en 2002.

BACKGROUND: To update full time educated youth data on smoking prevalence related to gender and to assess perception and behaviour related to smoking, we have led a self-administrated question-study from January to June 2002 in Abidjan with students from 8 to 22 years old. METHODS: Our population was divided in 3 groups: T1 (812 years), T2 (13-17 years) and T3 (18-22 years). The size of each group has been determined using the smoking estimated rate in each of them. RESULTS: 2742 students had returned a well-full questionnaire, with the following rates, expressed by mean and standard deviation in%: a total smoking rate at 7.9 +/- 0.5, with statistic difference between boys and girls (11 +/- 0,8 versus 3,7 +/- 0,5; p<0.001). This rate increased with age: 3.7 +/- 0.8 in T1; 12.9 +/- 1.0 in T2 and 17.1 +/- 1,1% in T3. Globally, the rate was 0.7 +/- 0.2 for regular smokers (>or=1 cigarette/day) (10% of C.D.T.) and 1.7 +/- 0.2% for ex-smokers. 99.2% of current smokers used cigarettes only. On average, the tobacco consumption was 3.4 cigarettes/day. In non-smokers group, 88% had respiratory symptoms linked to smoke exposure, with 17% of major dyspnea. Non smokers reported public places as the most frequent (66.7 +/- 1.3%) and the highest long time exposure (44.3 +/- 1.9%) places to second hand smoke. DISCUSSION: A similar smoking prevalence between asthmatics and non-asthmatics subjects, and between sporty type and non sporty type subjects, suggested that students had superficial knowledge or under assessment on smoking detrimental effect. However, their perception of smoking health hazard was sufficient to give 95 +/- 1% favourable opinions on necessary smoking place regulations and 85 +/- 1% favourable opinions on tobacco product advertising ban. CONCLUSION: The epidemiological and behaviour information given by this study might contribute to the development of a national youth tobacco control program, provided a complementary national survey would be led including non educated youth.

[Effect of smoking on PaO2 at rest and during moderate exercise]. / Effet du tabagisme sur la PaO2, au repos et au cours d'un effort physique modéré.

The most data on smoker's arterial oxygen tension (PaO2) were carried out at rest and from non arterial blood sample. The aim of this retrospective study was to compare smokers and nonsmoker's arterial oxygen tension (PaO2) at rest and during a moderate exercise. 98 male smokers between 23 and 69 years old and 98 male nonsmokers with the same age bracket were recruited among subjects submitted to arterial blood gas analysis according to the following protocol: 2 arterial blood samples were taken at rest, with an interval of 5 minutes, followed by a third one taken at the end of a moderate effort (50 watts during 5 minutes) on a bicycle in the supine position. Wilcoxon's test was used to compare the measured biological parameters between smokers and nonsmokers. Unlike nonsmokers, smoker's PaO2 increased meaning fully during moderate exercise. However, like at rest, it remained lower than nonsmoker's PaO2.: 87.6 +/- 15.8 mmHg Versus 94.1 +/- 10.4 mmHg (p < 0.0001). These beneficial effects of exercise on smoker's PaO2, although limited among heavy smokers group, suggested that hypoxia observed at rest must be due to troubles in ventilation/perfusion ratio in the lungs. In comparison to nonsmokers, the most significantly hypoxia was founded in smokers between 40 and 59 years old. The variation of PaO2 in nonsmokers was normal in comparison with age, but strongly disturbed in smokers at rest as well as during a moderate exercise, despite the lack of correlation between PaO2 and the intensity of tobacco consumption (expressed as number of pack-years). Thus, the smokers' PaO2 deterioration concerned together its value and its variation in comparison with age.

Disappearance of molsidomine effects on pulmonary circulation of patients with chronic obstructive pulmonary disease after a three week treatment.

The effect of oral molsidomine (M) on the pulmonary artery hypertension of patients with chronic obstructive pulmonary disease (COPD) was investigated during an acute study (4 mg once) and after a 3 week-treatment (3 times 4 mg a day), on a double-blind basis in 16 patients, 8 receiving a placebo, and 8 molsidomine. Ventilatory and cardiocirculatory indices were obtained at rest and during exercise. When acutely given, molsidomine reduces the mean pulmonary arterial pressure (PAP), the pulmonary vascular resistance (PVR) and the arterial O2 partial pressure (PaO2), increasing heart rate (HR) as well as the alveo-arterial O2 partial pressure difference (P(A-a)O2). During exercise, pulmonary arterial pressure and pulmonary vascular resistance decrease while heart rate increases without modification of arterial blood gases. After a 3-week treatment, molsidomine no more improves any index but significantly reduces cardiac output during exercise and consequently the O2 delivery to the tissues. The same feature has already been observed for other nitrates. It thus seems inappropriate to prescribe nitrates or nitrate-like drugs to chronic obstructive pulmonary disease patients with a view to lower their pulmonary hypertension.

Paradoxical evolution of arterial blood gases during exercise in patients with chronic obstructive bronchitis.

In more than a thousand chronic obstructive lung disease (COLD) patients we have observed in six cases, that exercise-induced hypercapnia was accompanied by a concomitant improvement in arterial oxygen tension (PaO2) and a decrease in the alveolo-arterial O2. This behaviour was not due to technical errors. We explained the increase in PaO2 during exercise by three nonmutually exclusive mechanisms: 1) an increase in the respiratory quotient; 2) the exercise induced increase in alveolar ventilation, although inadequate to match the increase in CO2 production, would be redistributed to previously poorly ventilated regions of the lung, these regions therefore receiving enough oxygen to arterialize the blood flowing through the alveolar capillaries; 3) alternatively, perfusion would be redistributed in a more efficient way during exercise, so that even in the presence of hypoventilation, oxygenation would be improved.