• Open Access

The effects of social status on biological aging as measured by white-blood-cell telomere length

Authors


  • T. D. Spector and A. Aviv designed and coordinated the study and participated in the preparation of the manuscript. L. F. Cherkas and J. L. Hunkin collected and verified information of study participants and participated in preparation of the manuscript. A. M. Valdes participated in the statistical analysis and in the preparation of the manuscript. G. L. Surdulescu, J. Gardner and M. Kimura carried out the sample preparation and telomere assays.


Professor Tim Spector, Twin Research & Genetic Epidemiology Unit, St Thomas’ Hospital, London SE1 7EH, UK. Tel.: 020 7188 6765; fax: 020 7188 6718; e-mail: tim.spector@kcl.ac.uk

Summary

Low socio-economic status (SES) is associated with a shortened life expectancy, but its effect on aging is unknown. The rate of white-blood-cell (WBC) telomere attrition may be a biological indicator of human aging. We tested the hypothesis that SES is associated with telomere attrition independent of known risk factors influencing the aging process. We studied 1552 female twins. A venous blood sample was taken from each twin and isolated WBCs used for extraction of DNA. Terminal restriction fragment length (TRFL) was measured. Questionnaire data were collected on occupation, education, income, smoking, exercise, height and weight. Standard multiple linear regression and multivariate analyses of variance tested for associations between SES and TRFL, adjusting for covariates. A discordant twin analysis was conducted on a subset to verify findings. WBC telomere length was highly variable but significantly shorter in lower SES groups. The mean difference in TRFL between nonmanual and manual SES groups was 163.2 base pairs (bp) of which 22.9 bp (∼14%) was accounted for by body mass index, smoking and exercise. Comparison of TRFL in the 17 most discordant SES twin pairs confirmed this difference. Low SES, in addition to the harmful effects of smoking, obesity and lack of exercise, appears to have an impact on telomere length.

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