African ancestry, early life exposures, and respiratory morbidity in early childhood.

BACKGROUND: Racial disparities persist in early childhood wheezing and cannot be completely explained by known risk factors. OBJECTIVE: To evaluate the associations of genetic ancestry and self-identified race with early childhood recurrent wheezing, accounting for socio-economic status (SES) and early life exposures. METHODS: We studied 1034 children in an urban, multi-racial, prospective birth cohort. Multivariate logistic regression was used to evaluate the association of genetic ancestry as opposed to self-identified race with recurrent wheezing (>3 episodes). Sequential models accounted for demographic, socio-economic factors and early life risk factors. Genetic ancestry, estimated using 150 ancestry informative markers, was expressed in deciles. RESULTS: Approximately 6.1% of subjects (mean age 3.1 years) experienced recurrent wheezing. After accounting for SES and demographic factors, African ancestry (OR: 1.16, 95% CI: 1.02-1.31) was significantly associated with recurrent wheezing. By self-reported race, hispanic subjects had a borderline decrease in risk of wheeze compared with African Americans (OR: 0.44, 95% CI: 0.19-1.00), whereas white subjects (OR: 0.46, 95% CI: 0.14-1.57) did not have. After further adjustment for known confounders and early life exposures, both African (OR: 1.19, 95% CI: 1.05-1.34) and European ancestry (OR: 0.84, 95% CI: 0.74-0.94) retained a significant association with recurrent wheezing, as compared with self-identified race (OR(whites) : 0.31, 95% CI: 0.09-1.14; OR(hispanic) : 0.47, 95% CI: 0.20-1.08). There were no significant interactions between ancestry and early life factors on recurrent wheezing. CONCLUSIONS AND CLINICAL RELEVANCE: In contrast to self-identified race, African ancestry remained a significant, independent predictor of early childhood wheezing after accounting for early life and other known risk factors associated with lung function changes and asthma. Genetic ancestry may be a powerful way to evaluate wheezing disparities and a proxy for differentially distributed genetic and early life risk factors associated with childhood recurrent wheezing.

Role of upper esophageal reflex and belch reflex dysfunctions in noncardiac chest pain.

Fifty-four patients examined for noncardiac chest pain (NCCP), showing no esophageal motor disorder or gastroesophageal reflux disease compatible with NCCP, were subjected to an intraesophageal balloon distension test and a study of the belching reflex provoked by intraesophageal air injection. Thirty-three control subjects were also studied, allowing us to define high-threshold belchers (group I) as those who belched during two of three 40-ml distensions and low-threshold belchers (group II) as those who did not. The balloon distension test induced NCCP in 64% of the patients in group I, and in 14% of the patients in group II (P < 0.01). High-threshold belching was a factor favoring the positivity of the balloon distension test. This result supports the hypothesis that esophageal distension by air due to a belching disorder may be the mechanism responsible for NCCP in some patients with an abnormal sensitivity to balloon distension.

[Chronologic relationship between gastroesophageal reflux and asthma. Simultaneous study of the measured pH and respiratory function]. / Relation chronologique entre reflux gastro-oesophagien et asthme. Etude simultanée de la pH métrie et de la fonction respiratoire.

UNLABELLED: The aim of the study was: 1) to define the frequency of gastroesophageal reflux (GER) in asthmatics; 2) to study a possible relationship between episodes of GER and changes in airflow obstruction while maintaining as far as possible physiological conditions. Nineteen consecutive patients (aged 40.3 +/- 19 years) presenting with severe asthma requiring continuous treatment, were studied in a stable period. All treatments were stopped for 12 hours before the examination, except corticosteroids and sustained theophylline. Esophageal pH was measured continuously one hour before and three hours after a standardized meal. Respiratory function was measured every 30 minutes using a miniaturized spirometer which enabled the measurement of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1-VC ratio: 1) the frequency of pathological GER was defined by a Kaye's score greater than 90 and was 32%; 2) there was no significant correlation between the individual changes in FEV1 and different variables for the pH measured in the 30 mn before the measurement of bronchial obstruction (number of GER episodes, duration of GER, duration of the last GER episode, time of the last GER); 3) we have found no significant difference between the variation of FEV1 above or below 10% of the best FEV1 of each patient in relation to the quality (intensity, duration, delay) of GER episodes recorded 10 minutes before the spirometry. IN CONCLUSION: in severe asthmatics these results: 1) confirm the high frequency of pathological GER; 2) do not allow the establishment of a direct causal relationship between GER episodes and occurrence of a bronchial obstruction.

[Reduction of postprandial gastroesophageal reflux with sodium alginate in suspension. Multicenter pH study in 21 patients]. / Réduction du reflux gastro-oesophagien postprandial par l'alginate de sodium suspension. Etude pH-métrique multicentrique chez 21 malades.

The purpose of this study was to ascertain the pharmacological effectiveness of sodium alginate liquid in the treatment of gastroesophageal acid reflux. The pharmacological test selected was 3 hours postprandial oesophageal pH, because of the physico-chemical properties of this drug. Twenty-one patients of both sexes were included in this study. The initial pH measurement served both as inclusion criteria, by confirming the presence of gastric acid reflux, and as reference for the evaluation of the effect of sodium alginate liquid by a second pH determination after treatment. After treatment with sodium alginate liquid, the number and mean duration of episodes of reflux, as well as the time spent at each pH level, had significantly decreased as compared to the initial value. The gastroesophageal reflux score was significantly reduced during the second hour in recumbent posture, but none of the different parameters studied separately (number and mean duration of episodes of reflux and time spent at each pH level) was significantly decreased. This study demonstrates the pharmacological effectiveness of the drug during the post prandial period and indicates that it is more effective in upright than in supine position.

[Ambulatory recording of esophageal pH over a 24-hour period in a population of 27 control subjects: analysis of technical and methodological factors influencing results]. / Enregistrement ambulatoire du pH oesophagien pendant 24 heures dans une population de 27 témoins: analyse des facteurs techniques et méthodologiques influençant les résultats.

Twenty-four hour pH monitoring is used increasingly as a technique for diagnosis of gastro-esophageal reflux (GER). The Synectics recording apparatus (Stockholm, Sweden) was used in 27 ambulatory control subjects in order to: identify the variations of the data-dependent factors (electrodes, buffer solutions, calibration, placement of esophageal electrode). The consequences of these variations were evaluated by studying the measurement deflection after 24 h, baseline variations, and a comparative double pH esophageal recording with reference equipment for 3 h postprandial; to provide normal values for several parameters of GER measurement under the conditions of this study (total number of reflux, number of reflux episodes longer than 5 min, duration of the longest reflux, percentage of time during which pH was less than 4.0). Important interindividual variations were observed. When interpreting the results provided by this type of apparatus, one should take into account these large variations due, first, to the technique used and second, to the conditions of ambulatory recording.

[Gastric emptying of a solid-liquid meal in gastroesophageal reflux in adults]. / Vidange gastrique d'un repas solide-liquide au cours du reflux gastro-oesophagien chez l'adulte.

Several studies concerning the relationships between gastroesophageal reflux (GOR), gastric emptying and esophageal motility are available. So far, results have been contradictory. The purpose of this work was to study gastric emptying in patients with GOR; to search for simultaneous esophageal motility disorders and to specify their type and frequency; to establish a potential relationship between motor disorders of the esophagus and the stomach in these patients. Thirty-two consecutive patients were selected according to clinical criteria, i.e. presence of at least two of the three characteristic symptoms of GOR, and the data of a three-hour post-prandial pH-metry. Gastric stasis related clinical manifestations (nausea, post-prandial vomiting, sensation of abdominal distension or of post-prandial epigastric fullness) were also searched for in all patients. A gastroscopy allowed to score esophagitis in each case. All patients, including adult controls underwent an esophageal manometry as well as a radionuclide determination of gastric emptying, after isotopic labelling of the solid (S) and liquid (L) phases of a test meal. The results showed that there was no significant modification of gastric emptying of the S and L phases of the meal in the group of patients with GOR whatever the intensity of the reflux, judged on the pH-metry results and the endoscopic data. Thus the average time of gastric half-emptying of S and L was respectively 115 and 52 min for the patients vs 111 and 51 min for the control group. As well, no correlation was found between the gastric emptying parameters and the presence or absence of clinical signs of gastric stasis or the amplitude of esophageal contraction waves. On an individual basis, two patients showed a significant decrease in gastric emptying of either the S or L phases without any attendant modification in the kinetics of the other. These results suggest that, in the adult, gastric emptying cannot be considered to be a determining factor of GOR and there are no diffuse motility disorders of the upper digestive tract during this illness.