Factors Associated with Early Sexual Activity in Adolescents Residing in an Urban Area of Northeastern Mexico Who Use WhatsApp or Facebook.

Early sexual activity has been associated with unplanned pregnancy and sexually transmitted infections. In recent decades, the prevalence of early sexual activity and social media use has increased. However, the relationship between these variables has been little studied. Consequently, we examined the relationships of some factors present in the family and personal environment with early sexual activity in adolescents who use and do not use the WhatsApp and Facebook platforms. Through a cross-sectional study, data from 1328 adolescents aged 13 to 19 years were analyzed. Data collection was carried out using a self-administered questionnaire. Of the total participants, 35.7% reported early sexual activity, and 37.7% reported using social networks such as WhatsApp and Facebook. The mean age of onset of sexual activity was 15.59 ± 1.56 years. Multivariate logistic regression analysis showed significant associations of not studying (adjusted OR 4.70; CI 95% 1.31-16.78), consuming alcohol (adjusted OR 3.71; CI 95% 2.44-5.65) and having parents who consumed alcoholic beverages in the home (adjusted OR 1.48; 95% CI 1.03-2.12) with ESA. In the family and personal environment, some factors favored early sexual activity in young people who used the WhatsApp and Facebook applications. This information should be used by authorities in the health and education sectors to strengthen preventive programs targeting health risk habits and behaviors in adolescents.

Structural basis for substrate specificity of heteromeric transporters of neutral amino acids.

Despite having similar structures, each member of the heteromeric amino acid transporter (HAT) family shows exquisite preference for the exchange of certain amino acids. Substrate specificity determines the physiological function of each HAT and their role in human diseases. However, HAT transport preference for some amino acids over others is not yet fully understood. Using cryo-electron microscopy of apo human LAT2/CD98hc and a multidisciplinary approach, we elucidate key molecular determinants governing neutral amino acid specificity in HATs. A few residues in the substrate-binding pocket determine substrate preference. Here, we describe mutations that interconvert the substrate profiles of LAT2/CD98hc, LAT1/CD98hc, and Asc1/CD98hc. In addition, a region far from the substrate-binding pocket critically influences the conformation of the substrate-binding site and substrate preference. This region accumulates mutations that alter substrate specificity and cause hearing loss and cataracts. Here, we uncover molecular mechanisms governing substrate specificity within the HAT family of neutral amino acid transporters and provide the structural bases for mutations in LAT2/CD98hc that alter substrate specificity and that are associated with several pathologies.

Asociación de la violencia obstétrica, control prenatal y embarazo no planeado con la prematurez / Association of obstetric violence, prenatal control, and unplanned pregnancy with prematurity

Resumen La prematurez (PM) neonatal es un problema mayor de salud pública en el mundo, debido a su frecuencia de presentación y los años de vida potencialmente perdidos; además, es la principal causa de muerte en menores de cinco años. Entre las consecuencias negativas de la PM están las discapacidades del aprendizaje, visual y auditiva. Múltiples son los factores asociados a la PM; algunos pueden ser detectados y modificados de forma oportuna en las consultas prenatales y también, en las preconcepcionales. Por otro lado, la PM no es solamente responsabilidad del prestador de los servicios de salud, sino también del sistema de salud, el cual, debe otorgar los recursos mínimos necesarios para monitorear y mantener a la embarazada en un estado óptimo de salud para evitarla, y en caso de presentarse, debe contar con la infraestructura hospitalaria básica que permita la viabilidad del producto y evitar su muerte. Aunado a lo anterior, se debe de considerar la responsabilidad de la paciente y su pareja, debido a que en ellos recae la obligación de llevar un estilo de vida saludable y acudir a las consultas preconcepcionales y control prenatal.

Abstract Neonatal prematurity (MP) is a major public health problem in the world, due to its presentation frequency and the years of life potentially lost; In addition, it is the main cause of death in children under five years of age. Among the negative consequences of MP are learning, visual and hearing disabilities. There are multiple factors associated with MP; some can be detected and modified in a timely manner in prenatal consultations and in preconception. On the other hand, MP is not only responsibility of the health service provider, but also of the health system, which must grant the minimum resources necessary to monitor and maintain the pregnant woman in an optimal state of health to avoid it, and if it occurs, the hospital must have the basic infrastructure that allows the viability of the product and prevents its death. In addition, the responsibility of the patient and her partner must be considered since they are obliged to lead a healthy lifestyle and attend preconception consultations and prenatal care.

Risk factors of non-adherence to guidelines for the prevention of COVID-19 among young adults with asthma in a region with a high risk of a COVID-19 outbreak.

OBJECTIVE: SARS-CoV-2 disease 2019 (COVID-19) is highly contagious and spreads rapidly. The application of preventive measures has proven to be the best strategy to minimize the number of patients and the dissemination of and deaths from COVID-19. The objective of this study was to determine the risk factors that limit the adherence of asthmatic patients to measures that prevent COVID-19 among residents of a region with a high risk of a COVID-19 outbreak. METHODS: Through a cross-sectional study, data from 2,372 participants aged 16-24 years were analyzed. To collect their information, a questionnaire was constructed using the Google Forms tool. Due to the prevention measures in place for COVID-19, the home quarantine of many people, and the lack of socialization, the questionnaire was distributed through email (Internet) and WhatsApp. A logistic regression analysis was performed to determine the relationship between the variables. RESULTS: The prevalence of asthma was 12.2%, and non-adherence to the guidelines for the prevention of COVID-19 was 53.1%. Approximately 30.8% of asthma patients did not comply with the basic prevention measures for COVID-19. The results of the logistic regression analysis showed that being male, active smoking, and believing that COVID-19 is not a more severe disease for people suffering from asthma than others were associated with non-adherence to the basic protection measures established in the guidelines for the prevention of COVID-19. CONCLUSIONS: It is important for health professionals to advise asthma patients to comply with the basic measures of protection against COVID-19 and timely use medications for asthma control.

Regulation of RUVBL1-RUVBL2 AAA-ATPases by the nonsense-mediated mRNA decay factor DHX34, as evidenced by Cryo-EM.

Nonsense-mediated mRNA decay (NMD) is a surveillance pathway that degrades aberrant mRNAs and also regulates the expression of a wide range of physiological transcripts. RUVBL1 and RUVBL2 AAA-ATPases form an hetero-hexameric ring that is part of several macromolecular complexes such as INO80, SWR1, and R2TP. Interestingly, RUVBL1-RUVBL2 ATPase activity is required for NMD activation by an unknown mechanism. Here, we show that DHX34, an RNA helicase regulating NMD initiation, directly interacts with RUVBL1-RUVBL2 in vitro and in cells. Cryo-EM reveals that DHX34 induces extensive changes in the N-termini of every RUVBL2 subunit in the complex, stabilizing a conformation that does not bind nucleotide and thereby down-regulates ATP hydrolysis of the complex. Using ATPase-deficient mutants, we find that DHX34 acts exclusively on the RUVBL2 subunits. We propose a model, where DHX34 acts to couple RUVBL1-RUVBL2 ATPase activity to the assembly of factors required to initiate the NMD response.

Structural basis of Focal Adhesion Kinase activation on lipid membranes.

Focal adhesion kinase (FAK) is a key component of the membrane proximal signaling layer in focal adhesion complexes, regulating important cellular processes, including cell migration, proliferation, and survival. In the cytosol, FAK adopts an autoinhibited state but is activated upon recruitment into focal adhesions, yet how this occurs or what induces structural changes is unknown. Here, we employ cryo-electron microscopy to reveal how FAK associates with lipid membranes and how membrane interactions unlock FAK autoinhibition to promote activation. Intriguingly, initial binding of FAK to the membrane causes steric clashes that release the kinase domain from autoinhibition, allowing it to undergo a large conformational change and interact itself with the membrane in an orientation that places the active site toward the membrane. In this conformation, the autophosphorylation site is exposed and multiple interfaces align to promote FAK oligomerization on the membrane. We show that interfaces responsible for initial dimerization and membrane attachment are essential for FAK autophosphorylation and resulting cellular activity including cancer cell invasion, while stable FAK oligomerization appears to be needed for optimal cancer cell proliferation in an anchorage-independent manner. Together, our data provide structural details of a key membrane bound state of FAK that is primed for efficient autophosphorylation and activation, hence revealing the critical event in integrin mediated FAK activation and signaling at focal adhesions.

RPAP3 C-Terminal Domain: A Conserved Domain for the Assembly of R2TP Co-Chaperone Complexes.

The Rvb1-Rvb2-Tah1-Pih1 (R2TP) complex is a co-chaperone complex that works together with HSP90 in the activation and assembly of several macromolecular complexes, including RNA polymerase II (Pol II) and complexes of the phosphatidylinositol-3-kinase-like family of kinases (PIKKs), such as mTORC1 and ATR/ATRIP. R2TP is made of four subunits: RuvB-like protein 1 (RUVBL1) and RuvB-like 2 (RUVBL2) AAA-type ATPases, RNA polymerase II-associated protein 3 (RPAP3), and the Protein interacting with Hsp90 1 (PIH1) domain-containing protein 1 (PIH1D1). R2TP associates with other proteins as part of a complex co-chaperone machinery involved in the assembly and maturation of a growing list of macromolecular complexes. Recent progress in the structural characterization of R2TP has revealed an alpha-helical domain at the C-terminus of RPAP3 that is essential to bring the RUVBL1 and RUVBL2 ATPases to R2TP. The RPAP3 C-terminal domain interacts directly with RUVBL2 and it is also known as RUVBL2-binding domain (RBD). Several human proteins contain a region homologous to the RPAP3 C-terminal domain, and some are capable of assembling R2TP-like complexes, which could have specialized functions. Only the RUVBL1-RUVBL2 ATPase complex and a protein containing an RPAP3 C-terminal-like domain are found in all R2TP and R2TP-like complexes. Therefore, the RPAP3 C-terminal domain is one of few components essential for the formation of all R2TP and R2TP-like co-chaperone complexes.

A complex IRES at the 5'-UTR of a viral mRNA assembles a functional 48S complex via an uAUG intermediate.

Taking control of the cellular apparatus for protein production is a requirement for virus progression. To ensure this control, diverse strategies of cellular mimicry and/or ribosome hijacking have evolved. The initiation stage of translation is especially targeted as it involves multiple steps and the engagement of numerous initiation factors. The use of structured RNA sequences, called Internal Ribosomal Entry Sites (IRES), in viral RNAs is a widespread strategy for the exploitation of eukaryotic initiation. Using a combination of electron cryo-microscopy (cryo-EM) and reconstituted translation initiation assays with native components, we characterized how a novel IRES at the 5'-UTR of a viral RNA assembles a functional initiation complex via an uAUG intermediate. The IRES features a novel extended, multi-domain architecture, that circles the 40S head. The structures and accompanying functional data illustrate the importance of 5'-UTR regions in translation regulation and underline the relevance of the untapped diversity of viral IRESs.

Modeling of a 14 kDa RUVBL2-Binding Domain with Medium Resolution Cryo-EM Density.

The number of high-resolution structures of protein complexes obtained using cryo-electron microscopy (cryo-EM) is increasing rapidly. Cryo-EM maps of large macromolecular complexes frequently contain regions resolved at different resolution levels, and modeling atomic structures de novo can be difficult for domains determined at worse than 5 Å in the absence of atomic information from other structures. Here we describe the details and step-by-step decisions in the strategy we followed to model the RUVBL2-binding domain (RBD), a 14 kDa domain at the C-terminus of RNA Polymerase II associated protein 3 (RPAP3) for which atomic information was not available. Modeling was performed on a cryo-EM map at 4.0-5.5 Å resolution, integrating information from secondary structure predictions, homology modeling, restraints from cross-linked mass spectrometry, and molecular dynamics (MD) in AMBER. Here, we compare our model with the structure of RBD determined by NMR to evaluate our strategy. We also perform new MD simulations to describe important residues mediating the interaction of RBD with RUVBL2 and analyze their conservation in RBD homologous domains. Our approach and its evaluation can serve as an example to address the analysis of medium resolution regions in cryo-EM maps.

Structural mechanism for regulation of the AAA-ATPases RUVBL1-RUVBL2 in the R2TP co-chaperone revealed by cryo-EM.

The human R2TP complex (RUVBL1-RUVBL2-RPAP3-PIH1D1) is an HSP90 co-chaperone required for the maturation of several essential multiprotein complexes, including RNA polymerase II, small nucleolar ribonucleoproteins, and PIKK complexes such as mTORC1 and ATR-ATRIP. RUVBL1-RUVBL2 AAA-ATPases are also primary components of other essential complexes such as INO80 and Tip60 remodelers. Despite recent efforts, the molecular mechanisms regulating RUVBL1-RUVBL2 in these complexes remain elusive. Here, we report cryo-EM structures of R2TP and show how access to the nucleotide-binding site of RUVBL2 is coupled to binding of the client recruitment component of R2TP (PIH1D1) to its DII domain. This interaction induces conformational rearrangements that lead to the destabilization of an N-terminal segment of RUVBL2 that acts as a gatekeeper to nucleotide exchange. This mechanism couples protein-induced motions of the DII domains with accessibility of the nucleotide-binding site in RUVBL1-RUVBL2, and it is likely a general mechanism shared with other RUVBL1-RUVBL2-containing complexes.

Advances on the Structure of the R2TP/Prefoldin-like Complex.

Cellular stability, assembly and activation of a growing list of macromolecular complexes require the action of HSP90 working in concert with the R2TP/Prefoldin-like (R2TP/PFDL) co-chaperone. RNA polymerase II, snoRNPs and complexes of PI3-kinase-like kinases, a family that includes the ATM, ATR, DNA-PKcs, TRAPP, SMG1 and mTOR proteins, are among the clients of the HSP90-R2TP system. Evidence links the R2TP/PFDL pathway with cancer, most likely because of the essential role in pathways commonly deregulated in cancer. R2TP forms the core of the co-cochaperone and orchestrates the recruitment of HSP90 and clients, whereas prefoldin and additional prefoldin-like proteins, including URI, associate with R2TP, but their function is still unclear. The mechanism by which R2TP/PFLD facilitates assembly and activation of such a variety of macromolecular complexes is poorly understood. Recent efforts in the structural characterization of R2TP have started to provide some mechanistic insights. We summarize recent structural findings, particularly how cryo-electron microscopy (cryo-EM) is contributing to our understanding of the architecture of the R2TP core complex. Structural differences discovered between yeast and human R2TP reveal unanticipated complexities of the metazoan R2TP complex, and opens new and interesting questions about how R2TP/PFLD works.

Author Correction: RPAP3 provides a flexible scaffold for coupling HSP90 to the human R2TP co-chaperone complex.

In the originally published version of this article, the affiliation details for Hugo Muñoz-Hernández, Carlos F. Rodríguez and Oscar Llorca incorrectly omitted 'Centro de Investigaciones Biológicas (CIB), Spanish National Research Council (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain'. This has now been corrected in both the PDF and HTML versions of the Article.

RPAP3 provides a flexible scaffold for coupling HSP90 to the human R2TP co-chaperone complex.

The R2TP/Prefoldin-like co-chaperone, in concert with HSP90, facilitates assembly and cellular stability of RNA polymerase II, and complexes of PI3-kinase-like kinases such as mTOR. However, the mechanism by which this occurs is poorly understood. Here we use cryo-EM and biochemical studies on the human R2TP core (RUVBL1-RUVBL2-RPAP3-PIH1D1) which reveal the distinctive role of RPAP3, distinguishing metazoan R2TP from the smaller yeast equivalent. RPAP3 spans both faces of a single RUVBL ring, providing an extended scaffold that recruits clients and provides a flexible tether for HSP90. A 3.6 Å cryo-EM structure reveals direct interaction of a C-terminal domain of RPAP3 and the ATPase domain of RUVBL2, necessary for human R2TP assembly but absent from yeast. The mobile TPR domains of RPAP3 map to the opposite face of the ring, associating with PIH1D1, which mediates client protein recruitment. Thus, RPAP3 provides a flexible platform for bringing HSP90 into proximity with diverse client proteins.

Family, personal, and social factors associated with the non-use of contraceptive methods during the first sexual experience in adolescent women.

Unplanned pregnancy and sexually transmitted infections (STIs) in adolescents continue to be major health problems around the world. They are associated with sex that occurs without contraceptive protection. We determined the relationship of family, personal, and social factors with the non-use of any contraceptive method during the first sexual experience in 1409 adolescent women. The most significant risk factors were being less than 15 years of age and lacking knowledge and awareness about contraceptive methods. In the family environment, the risk factors were living in an incomplete family and the existence of a poor relationship among the father, the mother, and the adolescents. Socialization with friends who became sexually active at an early age was also associated with having sex for the first time without protection. This information should be used in sexual and reproductive education programmes to prevent unplanned pregnancy and STIs in adolescent women.

Unplanned pregnancy in adolescents: association with family structure, employed mother, and female friends with health-risk habits and behaviors.

Previous publications have suggested that living in a nonintact family household and socializing with girlfriends who smoke or who consume alcoholic beverages favor the development of health-risk habits and customs in adolescents. However, their relationship with unplanned pregnancy in adolescents has not been determined. We investigated the association between family structure, employed mother, and female friends with health-risk habits and behaviors with unplanned pregnancy in adolescents (n = 3,130). After adjusting for low maternal educational level and low family income, logistic regression analyses showed that having an employed mother and socializing with girlfriends who have health-risk habits or behaviors, rather than living in a nonintact family household, appear to be the most important health-risk factors for unplanned pregnancy in adolescents. It is important for health-care programs for adolescents to be revised and for their strategies be strengthened in order to reach the objectives for which they were created.

Association between family structure, maternal education level, and maternal employment with sedentary lifestyle in primary school-age children.

OBJECTIVE: To determine the association between family structure, maternal education level, and maternal employment with sedentary lifestyle in primary school-age children. METHOD: Data were obtained from 897 children aged 6 to 12 years. A questionnaire was used to collect information. Body mass index (BMI) was determined using the age- and gender-specific Centers for Disease Control and Prevention definition. Children were categorized as: normal weight (5(th) percentile≤BMI<85(th) percentile), at risk for overweight (85(th)≤BMI<95(th) percentile), overweight (≥ 95(th) percentile). For the analysis, overweight was defined as BMI at or above the 85(th) percentile for each gender. Adjusted odds ratios (adjusted ORs) for physical inactivity were determined using a logistic regression model. RESULTS: The prevalence of overweight was 40.7%, and of sedentary lifestyle, 57.2%. The percentage of non-intact families was 23.5%. Approximately 48.7% of the mothers had a non-acceptable educational level, and 38.8% of the mothers worked outside of the home. The logistic regression model showed that living in a non-intact family household (adjusted OR=1.67; 95% CI=1.04-2.66) is associated with sedentary lifestyle in overweight children. In the group of normal weight children, logistic regression analysis show that living in a non-intact family, having a mother with a non-acceptable education level, and having a mother who works outside of the home were not associated with sedentary lifestyle. CONCLUSION: Living in a non-intact family, more than low maternal educational level and having a working mother, appears to be associated with sedentary lifestyle in overweight primary school-age children.

Associação entre estrutura familiar, nível de escolaridade e emprego da mãe com estilo de vida sedentário em crianças em idade escolar primária / Association between family structure, maternal education level, and maternal employment with sedentary lifestyle in primary school-age children

OBJETIVO: Determinar a associação entre a estrutura familiar, o nível de escolaridade e emprego da mãe com o estilo de vida sedentário em crianças em idade escolar primária. MÉTODO: Foram obtidos os dados de 897 crianças com idade entre 6-12 anos. Foi utilizado um questionário para registrar as informações. O índice de massa corporal (IMC) foi determinado utilizando-se a definição específica para idade e sexo do Centro de Controle e Prevenção de Doenças. As crianças foram classificadas como: peso normal (5º-85º percentil), risco de sobrepeso (percentil > 85º e < 95º), sobrepeso (percentil > 95º). Para análise neste estudo, sobrepeso foi definido como IMC igual ou acima do 85º percentil para cada sexo. As razões de chance ajustadas (RCs ajustadas) foram determinadas para inatividade física utilizando o modelo de regressão logística. RESULTADOS: A prevalência de sobrepeso foi de 40,7%, e estilo de vida sedentário, 57,2%. O percentual de famílias de pais separados foi de 23,5%. Aproximadamente 48,7% das mães apresentaram um nível de escolaridade não aceitável, e 38,8% eram mães que trabalhavam fora de casa. Os resultados do modelo de regressão logística mostram que o fato de viver em um ambiente familiar com pais separados (RCs ajustadas = 1,67; IC 95% = 1,04-2,66) está associado ao estilo de vida sedentário em crianças com sobrepeso. No grupo de crianças com peso normal, a análise de regressão logística mostra que viver em uma família com pais separados, com a mãe apresentando nível de escolaridade não aceitável e/ou trabalhando fora de casa, não eram fatores associados a estilo de vida sedentário. CONCLUSÃO: Morar com uma família de pais separados, mais do que ter um baixo nível de escolaridade materno e uma mãe que trabalha fora, parece estar associado a um estilo de vida sedentário em crianças com sobrepeso em idade escolar primária.

OBJECTIVE: To determine the association between family structure, maternal education level, and maternal employment with sedentary lifestyle in primary school-age children. METHOD: Data were obtained from 897 children aged 6 to 12 years. A questionnaire was used to collect information. Body mass index (BMI) was determined using the age- and gender-specific Centers for Disease Control and Prevention definition. Children were categorized as: normal weight (5th percentile < BMI < 85th percentile), at risk for overweight (85th < BMI < 95th percentile), overweight (> 95th percentile). For the analysis, overweight was defined as BMI at or above the 85th percentile for each gender. Adjusted odds ratios (adjusted ORs) for physical inactivity were determined using a logistic regression model. RESULTS: The prevalence of overweight was 40.7%, and of sedentary lifestyle, 57.2%. The percentage of non-intact families was 23.5%. Approximately 48.7% of the mothers had a non-acceptable educational level, and 38.8% of the mothers worked outside of the home. The logistic regression model showed that living in a non-intact family household (adjusted OR = 1.67; 95% CI = 1.04-2.66) is associated with sedentary lifestyle in overweight children. In the group of normal weight children, logistic regression analysis show that living in a non-intact family, having a mother with a non-acceptable education level, and having a mother who works outside of the home were not associated with sedentary lifestyle. CONCLUSION: Living in a non-intact family, more than low maternal educational level and having a working mother, appears to be associated with sedentary lifestyle in overweight primary school-age children.

[Association between unplanned pregnancy and adolescence onset asthma]. / Asociación entre embarazo no planeado y asma de inicio en la adolescencia.

BACKGROUND: The association between asthma and pregnancy has been documented previously. The relationship between unplanned pregnancy and onset asthma in adolescence has not been studied. OBJECTIVE: To determine the association between unplanned pregnancy and adolescence onset asthma. MATERIAL AND METHODS: A cross-sectional study was done gathering information about asthma, unplanned pregnancy, family atopy and active or passive smoking in 3,130 adolescents aged 13-19 years. Asthma diagnosis was established through a selfquestionnaire based on the International Study of Asthma and Allergy in Childhood. Odds ratios for asthma were determined using logistic regression model and chi-squared test. RESULTS: Mean age of the participants was 16.37 ± 1.93 years. The prevalence of active smoking was 16.1%, of passive smoking 40% and of family atopy 9.8%. From the pregnant adolescents (785), 59.5% reported had planned not to have a child before pregnancy. Prevalence of wheezing during the year prior to the study was 9.3% and of wheezing during the pregnancy 2%. The prevalence of adolescence onset asthma was 5.4%. The age of initiation of asthma in the adolescence was 14.75 ± 1.60 years. The analysis showed that unplanned pregnancy has a slight risk for the development of asthma during adolescence. (Crude OR=1.03; CI 95% 1.02-1.05; p=0.000). CONCLUSION: Unplanned pregnancy, family atopy, active smoking and smoking friends are associated with the onset-asthma in the adolescence.

ANTECEDENTES: la asociación entre embarazo y asma se ha documentado previamente. La relación entre embarazo no planeado y asma de inicio en la adolescencia no se ha estudiado. OBJETIVO: determinar la asociación entre embarazo no planeado y asma de inicio en la adolescencia. MATERIAL Y MÉTODOS: estudio transversal en el que se recogió información de asma, embarazo no planeado, atopia familiar y tabaquismo activo o pasivo en 3,130 adolescentes de 13-19 años de edad. El asma se diagnosticó mediante un cuestionario autoadministrado basado en el utilizado en el Estudio Internacional de Asma y Alergia en Niños (ISAAC por sus siglas en inglés). Se determinó la razón de momios para asma mediante regresión logística y chi cuadrada. RESULTADOS: la edad media de las participantes fue 16.37 ± 1.93 años. La prevalencia del tabaquismo activo fue 16.1%, del pasivo 40% y la atopia familiar 9.8%. De las adolescentes embarazadas (785), 59.5% anotó que no había planeado tener un hijo antes del embarazo. La prevalencia de sibilancias durante el último año fue 9.3% y de sibilancias durante el embarazo 2%. La prevalencia de asma de inicio en la adolescencia fue 5.4%. La edad de inicio de asma en la adolescencia fue 14.75 ± 1.60 años. El análisis muestra que el embarazo no planeado tiene un ligero riesgo de padecer asma de inicio en la adolescencia (RM cruda=1.03; IC 95% 1.02-1.05). CONCLUSIONES: el embarazo no planeado, la atopia familiar, el tabaquismo activo y el tabaquismo de las amigas se asocian con el asma de inicio en la adolescencia.

Smoking in non-student Mexican adolescents with asthma: relation with family structure, educational level, parental approval of smoking, parents who smoke, and smoking friends.

INTRODUCTION: The association between some factors of the familial and social environment with smoking in non-student adolescents with asthma has not been explored. The aim of the study was to determine the association between family structure, educational level, parental approval of smoking, parents who smoke, and smoking friends with smoking in non-student adolescents with asthma. SUBJECTS AND METHODS: In a cross-sectional study, data were obtained by means of a structured questionnaire applied to 4,778 non-student adolescents aged 13-18 years. Diagnosis of asthma was performed using a questionnaire based on the International Study of Asthma and Allergy in Childhood questionnaire. The smoking habit was determined by application of a self-administered questionnaire. Odds ratios (OR) were determined for smoking using logistic regression. RESULTS: From the total sample, asthma prevalence was 6.6% and of active smoking, 34.2%. Age at initiation of asthma symptoms was 5.15±3.52 years, and that of active smoking was 13.65±2.07 years. Percentage of non-intact family (40.1 vs. 32.7%) was greater in the group of adolescents with asthma. Logistic regression models show that parental approval of smoking (adjusted OR=5.57; 95% confidence interval=2.48-12.51) and smoking friends (adjusted OR=2.92; 95% confidence interval=1.04-8.19) are associated with smoking in non-student adolescents with asthma. CONCLUSION: In this study, parental approval of smoking and having friends who smoke appear to be associated with smoking among non-student adolescents with asthma.

Association between obesity and asthma in preschool Mexican children.

The elevated prevalence of obesity as well as of asthma in preschool children has prompted investigators to speculate that obesity in childhood might be a causal factor in the development of asthma. The results obtained to date are debatable. We investigated the association between obesity and asthma in 1,160 preschool Mexican children. Diagnosis of asthma was performed using the International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire. The body mass index (BMI) in units of kg/m2 was determined, and children were categorized according to age- and gender-specific criteria, such as normal weight (5th-85th percentile), overweight (> or =85th and <95th percentile), and obesity (> or =95th percentile). Power test for logistic regression model was calculated. We found no association between overweight (adjusted OR = 1.02; 95% CI = 0.66-1.58), obesity (adjusted OR = 0.94; 95% CI = 0.68-1.30), and wheezing during the last year as determined by logistic regression model adjusted. We did not find an association between overweight, obesity, and asthma-associated hospitalizations. Further longitudinal studies are required to provide a better understanding of the relationship between obesity and asthma in preschool children.