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Previous issue date: 2016-11-25 / Introdu??o: o comprimento do tel?mero (TL) tem sido apontado como um poss?vel biomarcardor do envelhecimento celular, pois ocorre encurtamento fisiol?gico e progressivo do seu tamanho com o decorrer das replica??es celulares. Adicionalmente a esse encurtamento fisiol?gico, a disfun??o do TL tamb?m ? favorecida pela exposi??o ao estresse oxidativo, a inflama??o e ap?s o estresse psicossocial cr?nico. Existe ainda uma lacuna de conhecimento sobre as altera??es do TL durante o curso de vida em popula??es de mulheres idosas brasileiras, havendo a necessidade de estudos que possibilitem melhor entendimento da influ?ncia de contrastes sociais, condi??es socioecon?micas desfavor?veis, bem como exposi??o ao estresse social cr?nico no TL. Objetivos: 1) desenvolver uma revis?o sistem?tica para explorar as evid?ncias sobre associa??es entre estresse cr?nico durante o curso de vida e TL; 2) investigar poss?veis associa??es entre TL e adversidades na inf?ncia (social e econ?mica) em mulheres idosas com diferentes n?veis de escolaridade; 3) avaliar se o TL est? relacionado com doen?as cr?nicas e biomarcadores inflamat?rios em mulheres idosas; e 4) verificar se tel?meros mais curtos est?o associados com pior desempenho f?sico e maior autorrelato de limita??es funcionais em idosas. Materiais e m?todos: foi desenvolvida uma revis?o sistem?tica seguindo protocolo publicado em 2014. Concomitantemente, realizou-se um estudo observacional anal?tico de car?ter transversal com uma amostra de mulheres (n=106) com diferentes n?veis de escolaridade (ensino m?dio incompleto e ensino m?dio completo) na faixa et?ria de 64-74 anos e residentes no munic?pio de Natal (Rio Grande do Norte). Os dados foram coletados no per?odo de maio de 2014 a mar?o de 2015. A quantifica??o relativa do tamanho dos tel?meros (T/S) de leuc?citos foi realizada por meio da qPCR em tempo real em 83 mulheres. O question?rio padronizado incluiu informa??es sociodemogr?ficas, adversidades na inf?ncia, medidas antropom?tricas, autorrelato de sa?de, fun??o cognitiva, h?bitos de vida, condi??es cr?nicas de sa?de, capacidade funcional e desempenho f?sico (short physical performance battery, velocidade da marcha e for?a de preens?o manual). Foram analisados tamb?m biomarcadores inflamat?rios (interleucina-6 e prote?na c reativa). Para an?lise estat?stica, foram considerados p<0,05 e intervalos de confian?a de 95%. A normalidade dos dados foi verificada por meio do teste de Kolmogorov-Smirnov. Uma vez que o TL apresentou distribui??o n?o normal, foi realizada a transforma??o da medida em logaritmo natural para as an?lises subsequentes. Foram aplicados os testes T de Student para amostras independentes, Qui-quadrado e realizados modelos de regress?o linear m?ltipla ajustados pelos potenciais fatores de confus?o. Resultados: na revis?o sistem?tica, os resultados foram relatados de acordo com o Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Considerando os dezoito estudos inclu?dos na revis?o, no geral, observou-se que indiv?duos expostos ao estresse cr?nico, caracterizado por pobreza, exposi??o ? viol?ncia e cuidar de familiar doente apresentaram tel?meros mais curtos em rela??o aos indiv?duos n?o expostos ?s adversidades. An?lises do estudo transversal sobre TL e curso de vida mostraram que as idosas com ensino m?dio incompleto apresentaram maior TL em compara??o com o grupo de ensino m?dio completo (2.8 ? 0.9 e 2.0 ? 0.9, respectivamente; p = 0,0001). As mulheres que n?o conclu?ram o ensino m?dio foram expostas a mais adversidades na inf?ncia, e entre estas, as que sofreram duas ou mais adversidades apresentavam TL mais longo do que as mulheres expostas a ?1 adversidades (p = 0,03); entre as mulheres com, no m?nimo, ensino m?dio completo, essa diferen?a n?o foi significativa (p = 0,49). Em an?lises ajustadas por idade, escolaridade e abuso parental de ?lcool, observou-se tend?ncia linear de maior TL com maior n?mero de adversidades (p = 0,02) e a diferen?a no TL entre os n?veis de escolaridade permaneceu significativa (p = 0,002). N?o se observou diferen?a entre os grupos educacionais em rela??o ?s seguintes vari?veis: colesterol, triglic?rides, glicemia em jejum, hemoglobina glicada, prote?na c reativa e interleucina-6 (p>0,05). Condi??es cr?nicas de sa?de, medidas antropom?tricas, fatores de risco cardiovasculares e marcadores inflamat?rios n?o foram associados com o TL, mesmo ap?s o ajuste para idade, escolaridade e adversidades na inf?ncia (p>0,05). Igualmente, o TL n?o foi relacionado com nenhuma das vari?veis utilizadas para avaliar o desempenho f?sico e a capacidade funcional (p>0,05). Conclus?es: a rela??o positiva inesperada entre menor escolaridade e adversidades na inf?ncia com TL sugere que os participantes sobreviveram a duras condi??es de vida e que, provavelmente, essas mulheres t?m o TL mais longo em rela??o ao daquelas de sua coorte de nascimento. A aus?ncia de rela??o entre TL e doen?as cr?nicas, risco cardiovascular, inflama??o e desempenho f?sico, n?o deu suporte ? hip?tese de que o TL ? um biomarcador do envelhecimento na popula??o em estudo, por?m corrobora outros estudos que revelaram que o TL pode ser considerado um marcador de longevidade, independentemente de condi??es de sa?de e desempenho f?sico. / Introduction: Telomere length (TL) has been pointed out as a possible biomarker of cellular aging, as its physiological size progressively shortens with the course of cellular replications. In addition to this physiological shortening, TL dysfunction is also stimulated by exposure to oxidative stress, inflammation and after chronic psychosocial stress. There is also a lack of knowledge about TL changes during the course of life in populations of older Brazilian women, and there is a need for studies which foster a better understanding of the influence of social contrasts, unfavorable socioeconomic conditions, as well as exposure to chronic social stress in TL. Objectives: 1) To develop a systematic review to explore the evidence on associations between chronic stress over the life course and TL; 2) To investigate possible associations between TL and childhood adversities (social and economic) in older women with different levels of education; 3) To evaluate whether TL is related to chronic diseases and inflammatory biomarkers in older women; and 4) To verify whether shorter telomeres are associated with poorer physical performance and higher self-reported functional limitations in older adults. Materials and methods: A systematic review was developed following a protocol published in 2014. An observational cross-sectional analytical study was concomitantly carried out with a sample of women (n = 106) with different levels of education (incomplete secondary education and complete secondary education) in the age group of 64-74 years residing in the municipality of Natal (Rio Grande do Norte). Data were collected from May 2014 to March 2015. The relative quantification of leukocyte telomere size (T/S) was performed by real-time qPCR in 83 women. The standardized questionnaire included sociodemographic information, childhood adversities, anthropometric measures, self-reported health, cognitive function, life habits, chronic health conditions, functional capacity and physical performance (short physical performance battery, gait speed and manual grip strength). Inflammatory biomarkers (interleukin-6 and c-reactive protein) were also analyzed. For statistical analysis, p<0.05 and 95% confidence intervals were used. The normality of the data was verified by the Kolmogorov-Smirnov test. Since TL presented non-normal distribution, the transformation of the measure into natural logarithm was performed for subsequent analyzes. Student's t-tests were applied for independent samples, and Chi-square and multiple linear regression models were adjusted for potential confounding factors. Results: The results of the systematic review were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Considering the eighteen studies included in the review, we generally observed that individuals exposed to chronic stress, characterized by poverty, exposed to violence and/or caring for a sick relative had shorter telomeres compared to individuals who were not exposed to adversity. Analyzes of the cross-sectional study on TL and life course showed that the older adults with incomplete secondary education presented higher TL compared to the group of complete secondary education (2.8 ? 0.9 and 2.0 ? 0.9, respectively; p = 0.0001). Women who did not complete high school were exposed to more adversity in childhood, and among them, those who suffered two or more adversities had longer TL than women exposed to ?1 adversity (p = 0.03); among women with at least complete secondary education, this difference was not significant (p = 0.49). In analyzes adjusted for age, educational level and parental alcohol abuse, a linear trend of higher TL for greater number of adversities (p = 0.02) was observed, and the difference in TL between education levels remained significant (p = 0.002). No difference between the education groups was observed for the following variables: cholesterol, triglycerides, fasting glycemia, glycated hemoglobin, c-reactive protein and interleukin-6 (p>0.05). Chronic health conditions, anthropometric measures, cardiovascular risk factors and inflammatory markers were not associated with TL, even after adjusting for age, schooling and childhood adversities (p>0.05). Similarly, TL was not related to any of the variables used to assess physical performance or functional capacity (p>0.05). Conclusions: The unexpected positive relationship between TL and lower education level and childhood adversities suggests that participants survived harsh living conditions and that these women probably have longer TL in relation to others among their birth cohort. The lack of relationship between TL and chronic diseases, cardiovascular risk, inflammation and physical performance did not support the hypothesis that TL is an aging biomarker in the population under study, but corroborates other studies that have shown TL to be considered as a marker of longevity, regardless of health conditions and physical performance.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/22717 |
| Date | 25 November 2016 |
| Creators | Oliveira, Bruna Silva |
| Contributors | 39643069400, http://lattes.cnpq.br/4265185619165890, Sousa, Ana Carolina Patricio de Albuquerque, 04863490470, http://lattes.cnpq.br/3934508395223787, Pereira, Daniele Sirineu, 05435122660, http://lattes.cnpq.br/2171027311100046, Barb?-tuana, Flor?ncia Mar?a, 81547064072, http://lattes.cnpq.br/0541621833997095, Sousa, Maria Bernardete Cordeiro de, 06705430478, http://lattes.cnpq.br/8488760386226790, Guerra, Ricardo Oliveira |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM FISIOTERAPIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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