Timur Gültekin

Spatial Regression Models for Large-Cohort Studies Linking Community Air Pollution and Health

Cohort study designs are often used to assess the association between community-based ambient air pollution concentrations and health outcomes, such as mortality, development and prevalence of disease, and pulmonary function. Typically, a large number of subjects are enrolled in the study in each of a small number of communities. Fixed-site monitors are used to determine long-term exposure to ambient pollution. The association between community average pollution levels and health is determined after controlling for risk factors of the health outcome measured at the individual level (i.e., smoking). We present a new spatial regression model linking spatial variation in ambient air pollution to health. Health outcomes can be measured as continuous variables (pulmonary function), binary variables (prevalence of disease), or time-to-event data (survival or development of disease). The model incorporates risk factors measured at the individual level, such as smoking, and at the community level, such as air pollution. We demonstrate that the spatial autocorrelation in community health outcomes, an indication of not fully characterizing potentially confounding risk factors to the air pollution--health association, can be accounted for through the inclusion of location in the deterministic component of the model assessing the effects of air pollution on health or through a distance-decay spatial autocorrelation function in the stochastic component of the model, or both. We present a statistical approach that can be implemented for very large cohort studies. Our methods are illustrated with an analysis of the American Cancer Society cohort to determine whether the prevalence of heart disease is associated with concentrations of sulfate particles. From a statistical point of view, it appears that a location surface in the deterministic component of the model was preferred to a distance-decay autocorrelation structure in the models stochastic component.

Y-chromosome and autosomal STR diversity in four proximate settlements in Central Anatolia.

Due to the longstanding human presence in the region and the influence of social traditions, the genetic make-up of populations currently inhabiting Turkey (Anatolia) is quite complex. To characterize the patterns of genetic diversity in rural Central Anatolian villages, we analyzed samples collected at four local settlements for variation at 17 Y-chromosome STR and 15 autosomal STR loci. The resulting data reveal considerable diversity within these settlements, as well as some structure in the paternal genetic variation, with a limited number of haplotypes being shared between the communities. These findings have important implications for forensic studies of Turkish populations.

Components of Particulate Air Pollution and Emergency Department Visits in Chile

ABSTRACT The objective of the present study was to determine the association between several elements of particulates and Emergency Department (ED) visits in a general population sample. Daily time-series analyses tested the association between daily ED visit and air pollutants and components of particulates measured in Santiago Centro, a municipality, which includes downtown Santiago during the period from 2001 to 2006. The strongest individual effect was seen for elemental carbon. A 4.76 μg/m3 increase was associated with a relative risk (RR) of 1.12 (95% confidence interval [CI] = 1.10–1.14) increase in total ED visits, and a RR of 1.18 (95% CI = 1.16–1.21) for respiratory ED visit. Using factor analysis, the authors determined that traffic combustion-related particulates were significantly associated with ED visits. Among all the sources identified, traffic combustion-related particulates had the strongest association with ED visits. A factor indicating soil-sourced particles had a weaker but statistically significant observed morbidity effect. Of the many components of particulate air pollution, those from motor vehicle exhaust had the greatest observed effect on morbidity.

Prevalence of overweight and obesity in Turkish adults.

The aims of this study were to assess the prevalence and patterns of adult overweight and obesity in Turkey and discuss the impact of socio-environmental factors. A cross-sectional nationwide survey was carried out on 2100 adults (1050 males and 1050 females) aged 18 to 65 years from 7 geographic regions of Turkey. Data on height and weight were measured according to the Anthropometric Standardization Reference Manual and a questionnaire was applied to access the socio-economic status. The body mass index (BMI) (kg/m2), overweight and obesity were calculated, and percentiles were developed by LMS method. Mean BMI was 26.24 for males and 28.02 for females. Results showed that obesity was more pronounced among females (34.19%) than among males (20%). Logistic regression analysis revealed that older age and education level among females, and older age and occupational status among males have impact on obesity. Comparison of the present results with former nationwide studies conducted in Turkey showed that height and weight for both sexes have increased with the improved socio-economic conditions. In addition, increased weight and BMI needed to be monitored particularly for females in terms of acute health problems.

Growth of children living in the outskirts of Ankara: Impact of low socio-economic status

Background: Most studies of the growth of Turkish schoolchildren are limited to large cities and to subjects from high socio-economic background. Very little is known about growth and development of rural, suburban and low socio-economic children in Turkey. Aim: The purpose of this study is to compare height and weight of school-aged children of low socio-economic background with available growth data from high socio-economic strata, and to verify the possible influences of three socio-demographic parameters on their growth. Subjects and methods: The sample consisted of 1052 girls and 1223 boys, aged between 7–17 years, living in the outskirts of Ankara, a suburban area of poor socio-economic background. Centile distributions for height and weight were estimated by the LMS-method. ANOVA and Students t-test were used to compare mean z-scores for height and weight among the various categories of the socio-demographic parameters. Results: Children living in the outskirts of Ankara have lower mean values for height and weight when compared with growth data of upper socio-economic strata children. The differences were most pronounced during adolescence. Skinfolds were higher in girls than in boys at all ages (largest p ≤ 0.007). There was no clear relationship between growth and the number of siblings, the number of rooms in the house, the mothers and fathers education, and the fathers professional status (p>0.05), except for the height of girls (p < 0.05). Conclusion: It is suggested that the lower growth status of children living in the outskirts of Ankara is attributable to the poor socio-economic status of this suburban population, which has not changed over the past decades. It is postulated that the growth impairment during adolescence might be due to a reduced tempo of growth in these children. Résumé. Arrière plan: En Turquie, la plupart des études de croissance ont été limitées à des échantillons de grandes villes et de haut niveau socio-économique. On sait peu de choses sur les modalités de la croissance et du développement des enfants ruraux, périurbains et de niveau socio-économique modeste. But: Cette étude compare les statures et les poids d’enfants turcs de milieu socioéconomique modeste avec les données des strates socioéconomiques favorisées et analyse les influences éventuelles de trois facteurs sociodémographiques sur leur croissance. Sujets et méthodes: L’échantillon est formé de 1052 filles et de 1223 garçons âgés de 7 à 17 ans, vivant dans une zone périurbaine défavorisée de la banlieue d’Ankara. Les distributions de centiles pour la stature et pour le poids, ont été estimées par la méthode des moindres carrés et l’analyse de la variance et le test de Student ont été utilisés afin de comparer les z-scores moyens de la stature et du poids en fonction de diverses catégories de paramètres sociodémographiques. Résultats: Les enfants de la banlieue d’Ankara ont des valeurs moyennes de stature et de poids plus basses que celles des enfants de milieu favorisés, les différences étant plus prononcées lors de l’adolescence. Les plis cutanés sont plus épais chez les filles que chez les garçons quelque soit l’âge (p ≤ 0,007). Il n’y a pas d’association nette entre la croissance et le nombre de frères et sœurs, le nombre de pièces du foyer, l’éducation de la mère et du père et le statut professionnel du père (p>0,05), à l’exception de la stature des filles (p<0,05). Conclusion: Il est vraisemblable que les modalités de croissance moins favorables qu’on observe chez les enfants de la banlieue d’Ankara, soient dues à leur mauvais statut socioéconomique qui n’a pas changé au cours des récentes décennies. On postule que leur déficit de croissance au cours de l’adolescence peut être le fait d’un tempo de croissance réduit. Zusammenfassung. Hintergrund: Die meisten Wachstumsstudien an Türkischen Schulkindern sind auf große Städte und Probanden mit hohem sozioökonomischen Hintergrund beschränkt. In der Türkei ist sehr wenig über Wachstum und Entwicklung von Kindern aus ländlichen Regionen und Vorstädten und Kindern aus niedrigen sozioökonomischen Schichten bekannt. Ziel: Sinn dieser Studie ist es, Körperhöhe und Gewicht von Kindern mit niedrigem sozioökonomischen Hintergrund im Schulalter mit verfügbaren Wachstumsdaten aus hohen sozioökonomischen Schichten zu vergleichen und mögliche Einflüsse von drei soziodemographischen Parametern auf ihr Wachstum nachzuweisen. Probanden und Methoden: Die Stichprobe bestand aus 1052 Mädchen und 1223 Knaben im Alter zwischen 7 und 17 Jahren, die in den Vorstädten von Ankara wohnen, einem suburbanen Bezirk mit sozioökonomisch ärmlichem Hintergrund. Perzentilverteilungen für Körperhöhe und Gewicht wurden nach der LMS-Methode geschätzt. ANOVA und Students t-Test wurden verwendet, um mittlere Z-Werte für Körperhöhe und Gewicht zwischen den verschiedenen Kategorien der soziodemographischen Parameter zu vergleichen. Ergebnisse: Kinder, die in den Vorstädten von Ankara leben, haben, im Vergleich mit Wachstumsdaten aus der oberen sozioökonomischen Schicht, niedrigere Mittelwerte für Körperhöhe und Gewicht. Die Unterschiede waren während der Adoleszenz am stärksten ausgeprägt. In allen Altersgruppen waren Hautfettfalten bei Mädchen dicker als bei Knaben (maximal p<0,007). Es gab keine deutliche Korrelation zwischen Wachstum und Geschwisterzahl, Zimmerzahl im Hause, Bildungsgrad von Müttern und Vätern, und dem beruflichen Status des Vaters (p>0,05), mit Ausnahme der Körperhöhe von Mädchen (p<0,05). Zusammenfassung: Es wird angenommen, dass das geringere Wachstum von Kindern, die in den Vorstädten von Ankara leben, auf den ärmlichen sozioökonomischen Status dieser suburbanen Bevölkerung, der sich in den vergangenen Jahrzehnten nicht geändert hat, zurückzuführen ist. Es wird postuliert, dass der Kleinwuchs in der Adoleszenz die Folge eines verringerten Wachstumstempos dieser Kinder ist. Resumen. Antecedentes: la mayor parte de los estudios de crecimiento de los escolares turcos se limita a las grandes ciudades y a sujetos de nivel socioeconómico alto. Se sabe muy poco sobre el crecimiento y desarrollo de los niños rurales suburbanos de nivel socioeconómico bajo de Turquía. Objetivo: el propósito de este estudio es comparar la estatura y el peso de los escolares de nivel socioeconómico bajo con datos disponibles sobre el crecimiento de los estratos de nivel socioeconómico alto, y verificar las posibles influencias de tres parámetros sociodemográficos sobre su crecimiento. Sujetos y métodos: la muestra la componen 1.052 niñas y 1.223 niños, de 7 a 17 años de edad, residentes en los extrarradios de Ankara, un área suburbana de nivel socioeconómico pobre. Las distribuciones centilares de la estatura y el peso se estimaron mediante el método LMS. Se utilizaron un test ANOVA y la t de Student para comparar las puntuaciones z medias de la estatura y el peso entre las diferentes categorías según los parámetros sociodemográficos. Resultados: los niños que residen en los extrarradios de Ankara tenían menores valores medios de estatura y peso cuando se les comparó con los niños de los estratos socioeconómicos más altos. Las diferencias fueron más marcadas durante la adolescencia. Los pliegues eran mayores en las chicas que en los chicos a todas las edades (la mayor p<0,007). No había una relación clara entre el crecimiento y el tamaño de la fratría, el número de habitaciones de la casa, el nivel educativo de la madre y del padre y la situación profesional del padre (p>0,05), excepto para la estatura de las chicas (p<0,05). Conclusión: se sugiere que el menor nivel de crecimiento de los niños que viven en los extrarradios de Ankara es atribuible al bajo nivel socioeconómico de esta población suburbana, que no ha cambiado durante las últimas décadas. Se postula que las diferencias en el crecimiento durante la adolescencia podrían deberse a una reducción del ritmo de crecimiento en estos niños.

Do Socio-Demographic Characteristics Modify the Association Between Air Pollution and Mortality & Morbidity?

Sabit Cakmak1, Sara L. Martin4, Claudia Blanco Vidal2, Timur Gultekin3, Vladislav Brion4 and Maria Angelica Rubio5 1Health Canada, Ottawa, Department of Statistics, 2Area Descontaminacion Atmosferica, Comision Nacional del Medio Ambiente (CONAMA), 3Department of Anthropology, Ankara University, 4Health Canada, Ottawa, Department of Statistics 5Departamento de Ciencias del Ambiente, Facultad de Quimica y Biologia, Universidad de Santiago de Chile Centro de Desarrollo para la Nanociencia y Nanotecnologia (CEDENNA), 1,4Canada 2,5Chile 3Turkey

Elit Erkek Sporcuların Vücut Kompozisyonu Değerleri : Body Composition Values in Elite Male Athletes

The purpose of this study is to determine the body composition profiles and body composition dijferences in soccer, wrestlers, taehvondo, handball and weight 1 Prof. Dr. A. Ü. Dil ve Tarih-Coğrafya Fakültesi Antropoloji Bölümü Öğr. Gör. G. Ü. Beden Eğitimi ve Spor Yüksek Okulu 3 Araş. Dr. A. Ü. Dil ve Tarih-Coğrafya Fakültesi Antropoloji Böl. Ankara