A cross-sectional analysis of the association between perceived network social control and telomere length.

OBJECTIVE: Social control in the health domain refers to attempts by social network members to get an individual to modify their health behaviors. According to the dual effects model of social control, having one's health behavior controlled by others should be related to healthier behavioral change, but might arouse psychological distress as one may resent being controlled. Despite potential healthy behavior change, the stress of social control may thus be detrimental as interpersonal stress has been related to negative health outcomes. In the present study, the association between perceived social control and telomere length was tested to examine its association to biological outcomes. METHOD: In this cross-sectional study, a relatively healthy community sample of 140 middle age and older adults completed measures of perceived social control, perceived stress, and health behaviors. Peripheral blood mononuclear cells were used to determine telomere length. RESULTS: Main results showed that higher levels of perceived direct social network control were associated with shorter telomere length. These links were not influenced by statistical controls for medication use, self-rated health, trait hostility, and optimism. Perceived social control was also related to greater perceived stress but not health behaviors overall. However, neither perceived stress nor health behaviors mediated the link between social control and telomere length. CONCLUSIONS: Although the study design precludes strong inferences, these results suggest that perceived social control may be associated with cellular aging. These data also highlight the utility of integrating biological outcomes into social control models. (PsycINFO Database Record

Reproducibility of telomere length assessment: an international collaborative study.

BACKGROUND: Telomere length is a putative biomarker of ageing, morbidity and mortality. Its application is hampered by lack of widely applicable reference ranges and uncertainty regarding the present limits of measurement reproducibility within and between laboratories. METHODS: We instigated an international collaborative study of telomere length assessment: 10 different laboratories, employing 3 different techniques [Southern blotting, single telomere length analysis (STELA) and real-time quantitative PCR (qPCR)] performed two rounds of fully blinded measurements on 10 human DNA samples per round to enable unbiased assessment of intra- and inter-batch variation between laboratories and techniques. RESULTS: Absolute results from different laboratories differed widely and could thus not be compared directly, but rankings of relative telomere lengths were highly correlated (correlation coefficients of 0.63-0.99). Intra-technique correlations were similar for Southern blotting and qPCR and were stronger than inter-technique ones. However, inter-laboratory coefficients of variation (CVs) averaged about 10% for Southern blotting and STELA and more than 20% for qPCR. This difference was compensated for by a higher dynamic range for the qPCR method as shown by equal variance after z-scoring. Technical variation per laboratory, measured as median of intra- and inter-batch CVs, ranged from 1.4% to 9.5%, with differences between laboratories only marginally significant (P = 0.06). Gel-based and PCR-based techniques were not different in accuracy. CONCLUSIONS: Intra- and inter-laboratory technical variation severely limits the usefulness of data pooling and excludes sharing of reference ranges between laboratories. We propose to establish a common set of physical telomere length standards to improve comparability of telomere length estimates between laboratories.

Educational attainment and late life telomere length in the Health, Aging and Body Composition Study.

Morbidity and mortality are greater among socially disadvantaged racial/ethnic groups and those of lower socioeconomic status (SES). Greater chronic stress exposure in disadvantaged groups may contribute to this by accelerating cellular aging, indexed by shorter age-adjusted telomere length. While studies consistently relate shorter leukocyte telomere length (LTL) to stress, the few studies, mostly from the UK, examining associations of LTL with SES have been mixed. The current study examined associations between educational attainment and LTL among 2599 high-functioning black and white adults age 70-79 from the Health, Aging and Body Composition Study. Multiple regression analyses tested associations of race/ethnicity, educational attainment and income with LTL, adjusting for potential confounders. Those with only a high school education had significantly shorter mean LTL (4806 basepairs) than those with post-high school education (4926 basepairs; B=125, SE=47.6, p=.009). A significant interaction of race and education (B=207.8, SE=98.7, p=.035) revealed more beneficial effects of post-high school education for blacks than for whites. Smokers had shorter LTL than non-smokers, but the association of education and LTL remained significant when smoking was covaried (B=119.7, SE=47.6, p=.012). While higher income was associated with longer LTL, the effect was not significant (p>.10). This study provides the first demonstration of an association between educational attainment and LTL in a US population where higher education appears to have a protective effect against telomere shortening, particularly in blacks.