@article {8819, title = {Sex-Specific and Time-Varying Associations Between Cigarette Smoking and Telomere Length Among Older Adults.}, journal = {Am J Epidemiol}, volume = {184}, year = {2016}, month = {2016 12 15}, pages = {922-932}, abstract = {

Inconsistent associations between smoking and telomere length (TL) have been reported in epidemiologic studies, perhaps because of the time-varying nature of smoking behaviors. We estimated the associations of TL, which was measured by quantitative polymerase chain reaction using saliva DNA, with concurrent and past smoking status reported biennially for up to 16 years before TL measurement in~5,624 participants in the Health and Retirement Study (1992-2008). Smoking was associated with reduced TL when we used prospective data on smoking statuses among men and women, but the association was strongly attenuated among men in cross-sectional analyses. This attenuation was largely due to a higher rate of smoking cessation during the study period among men with shorter TL than among men with longer TL. Short TL was also associated with poorer overall health in men, which suggests that male smokers with short TL were more likely to quit smoking because of poor health. Analyses of years since cessation, smoking duration, and pack-years of smoking all support the hypothesis that increased cigarette use shortens TL. Our results provide a potential explanation for the inconsistent associations between smoking and TL reported in previous cross-sectional studies. Time-varying associations should be considered in future studies of smoking behavior, TL, aging, and disease risk.

}, keywords = {Aged, Aged, 80 and over, Aging, Biomarkers, DNA, Female, Health Status, Humans, Longitudinal Studies, Male, Middle Aged, Oxidative stress, Polymerase Chain Reaction, Prospective Studies, Saliva, Sex Distribution, Smoking, Smoking cessation, Telomere Shortening}, issn = {1476-6256}, doi = {10.1093/aje/kww102}, url = {http://aje.oxfordjournals.org/lookup/doi/10.1093/aje/kww102}, author = {Zhang, Chenan and Diane S. Lauderdale and Brandon L Pierce} } @article {8622, title = {Genetic susceptibility to accelerated cognitive decline in the US Health and Retirement Study.}, journal = {Neurobiol Aging}, volume = {35}, year = {2014}, month = {2014 Jun}, pages = {1512.e11-8}, abstract = {

Age-related cognitive decline is a major public health concern facing a large segment of the US population. To identify genetic risk factors related to cognitive decline, we used nationally representative longitudinal data from the US Health and Retirement Study to conduct genome-wide association studies with 5765 participants of European ancestry, and 890 participants of African ancestry. Mixed effects models were used to derive cognitive decline phenotypes from data on repeated cognitive assessments and to perform single nucleotide polymorphism-based heritability estimation. We found 2 independent associations among European-Americans in the 19q13.32 region: rs769449 (APOE intron; p = 3.1 {\texttimes} 10(-20)) and rs115881343 (TOMM40 intron; p = 6.6 {\texttimes} 10(-11)). rs769449 was also associated with cognitive decline among African-Americans (p = 0.005), but rs115881343 was not. Cross-sectional cognitive function showed moderate heritability (15\%-32\%) across several age strata (50-59, 60-69, 70-79 years), but the cognitive decline heritability estimate was low (\~{}5\%). These results indicate that despite multiple association signals for cognitive decline in the 19q13.32 region, inter-individual variation is likely influenced substantially by environmental factors.

}, keywords = {African Americans, Aged, Aged, 80 and over, Chromosomes, Human, Pair 9, Cognition, Cognition Disorders, Cross-Sectional Studies, Female, Gene-Environment Interaction, Genetic Predisposition to Disease, Genetic Variation, Genome-Wide Association Study, Humans, Male, Membrane Transport Proteins, Middle Aged, Phenotype, Polymorphism, Single Nucleotide, Risk Factors, United States}, issn = {1558-1497}, doi = {10.1016/j.neurobiolaging.2013.12.021}, author = {Zhang, Chenan and Brandon L Pierce} }