BACKGROUND:The impulse oscillometry system (IOS) is increasingly used to evaluate lung function, but individual results must be compared with appropriate reference values. We aimed to obtain such reference values in Mexican children and adolescents. METHODS: Healthy subjects were recruited from kindergartens and schools after their parents signed a consent letter. Respiratory system impedances (Zrs), resistances (Rrs), and reactances (Xrs) were measured at 5, 10, 15, and 20 Hz, and the resonant frequency, reactance area, and difference between Rrs5 minus Rrs20 were also calculated. RESULTS: After exclusion of 4 children who were unable to perform an acceptable IOS recording, the final population comprised 283 children (153 females) 2.7-15.4 y of age. As a group, girls tended to have lower Xrs5 and higher Zrs20 and Rrs20 values. In bivariate analyses, all IOS variables had good correlation with age, height, and weight, and a better straightline fitting was obtained through data transformation to the log 10 (age) or reciprocal (height and weight) values. Comparison of regression lines revealed small differences between males and females, especially in Xrs. Multiple linear regression analysis identified height as the most influential variable in the majority of IOS variables, but age also accounted for a moderate-to-large influence in the regression models in many IOS variables. CONCLUSIONS: In this study, we generated reference equations for each IOS variable in healthy children and adolescents. Although these equations were generated in a Mexican population, they are probably also applicable in other Latin American populations with the same ethnic background.

Because of the robust adjustment of the present study reference equations for the IOS, it can be recommended for both clinical and research purposes in our population. The differential adjustment of other equations underlines the need to obtain local reference values.

BackgroundRadiation pneumonitis (RP) is a frequent complication of concurrent chemoradiotherapy (CCRT) and is associated with severe symptoms that decrease quality of life and might result in pulmonary fibrosis or death. The aim of this study is to identify whether pulmonary function test (PFT) abnormalities may predict RP in non-small cell lung cancer (NSCLC) patients.MethodsA prospective multi-institutional study was conducted with locally advanced and oligometastatic NSCLC patients. All participants were evaluated at baseline, end of CCRT, week 6, 12, 24, and 48 post-CCRT. They completed forced spirometry with a bronchodilator, body plethysmography, impulse oscillometry, carbon monoxide diffusing capacity (DLCO), molar mass of CO2, six-minute walk test and exhaled fraction of nitric oxide (FeNO). Radiation pneumonitis was assessed with RTOG and CTCAE. The protocol was registered in www.clinicaltrials.gov (NCT01580579), registered April 19, 2012.ResultsFifty-two patients were enrolled; 37 completed one-year follow-up. RP ≥ Grade 2 was present in 11/37 (29%) for RTOG and 15/37 (40%) for CTCAE. Factors associated with RP were age over 60 years and hypofractionated dose. PFT abnormalities at baseline that correlated with the development of RP included lower forced expiratory volume in one second after bronchodilator (p = 0.02), DLCO (p = 0.02) and FeNO (p = 0.04). All PFT results decreased after CCRT and did not return to basal values at follow-up.ConclusionsFEV1, DLCO and FeNO prior to CCRT predict the development of RP in NSCLC. This study suggests that all patients under CCRT should be assessed by PFT to identify high-risk patients for close follow-up and early treatment.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0775-2) contains supplementary material, which is available to authorized users.

ObjectiveThe aim of this study was to analyze the factors enabling/limiting the use of improved cookstoves among rural fuel wood users from one mestizo and two indigenous communities eight years after an intervention in the state of Michoacan, in Mexico.MethodsA qualitative study with an ethnographic perspective was conducted in 2013/2014 based on 62 interviews with women who had participated in an improved firewood cookstove program in 2005. Thematic qualitative content analysis was performed.ResultsVery few women from the indigenous communities were using the improved cookstove at the time of the study; the majority had dismantled or had ceased using it; whereas most of those from the mestizo community were using it for all of their cooking activities. In the indigenous communities, characterized by extended families, uptake of new technology was limited by traditional routine practices, rearrangement of rooms in the house, attachment to the traditional stove, a low- or non-risk perception of woodsmoke; gender relations, insufficient training, non-compliance with program recommendations and design-related aspects. Conversely, in the mestizo community, the uptake of the improved cookstove was favored by routine cooking practices in a nuclear family, a previous use of a raised cookstove and social representations on the health-disease-death effects of woodsmoke vs. the health benefits of cooking with improved stoves. The sociocultural dimension of communities and the cookstove design are aspects that either favor or limit the use of improved cookstoves in indigenous and mestizo populations.ConclusionsEffective cookstove programs must take these elements into account from their early planning stages, and blend them into implementation and follow-up. Project communication, training and differentiated follow-up activities ensuring the operation and maintenance of the cookstove, should be designed according to the specific needs and traditions of each community; they should be based on the preferences and needs of the users.

IntroductionOur aim was to estimate the longitudinal effect of Socioeconomic status (SES) on lung function growth of Mexican children and adolescents.Materials and MethodsA cohort of Mexican children in third grade of primary school was followed with spirometry twice a year for 6 years through secondary school. Multilevel mixed-effects lineal models were fitted for the spirometric variables of 2,641 respiratory-healthy Mexican children. Monthly family income (in 2002 U.S. dollars [USD]) and parents’ years completed at school were used as proxies of SES.ResultsIndividuals with higher SES tended to have greater height for age, and smaller sitting height/standing height and crude lung function. For each 1-year increase of parents’ schooling, Forced expiratory volume in 1 sec (FEV1) and Forced vital capacity (FVC) increased 8.5 (0.4%) and 10.6 mL (0.4%), respectively (p <0.05) when models were adjusted for gender. Impact of education on lung function was reduced drastically or abolished on adjusting by anthropometric variables and ozone.ConclusionsHigher parental schooling and higher monthly family income were associated with higher lung function in healthy Mexican children, with the majority of the effect likely due to the increase in height-for-age.