title: Comparison of telomere length in black and white teachers from South Africa: the sympathetic activity and ambulatory blood pressure in Africans study.
abstract: OBJECTIVE
  Telomere length is a marker of biological aging that has been linked to cardiovascular disease risk. The black South African population is witnessing a tremendous increase in the prevalence of cardiovascular disease, part of which might be explained through urbanization. We compared telomere length between black South Africans and white South Africans and examined which biological and psychosocial variables played a role in ethnic difference in telomere length.
  
  
  METHODS
  We measured leukocyte telomere length in 161 black South African teachers and 180 white South African teachers aged 23 to 66 years without a history of atherothrombotic vascular disease. Age, sex, years having lived in the area, human immunodeficiency virus (HIV) infection, hypertension, body mass index, dyslipidemia, hemoglobin A1c, C-reactive protein, smoking, physical activity, alcohol abuse, depressive symptoms, psychological distress, and work stress were considered as covariates.
  
  
  RESULTS
  Black participants had shorter (median, interquartile range) relative telomere length (0.79, 0.70-0.95) than did white participants (1.06, 0.87-1.21; p < .001), and this difference changed very little after adjusting for covariates. In fully adjusted models, age (p < .001), male sex (p = .011), and HIV positive status (p = .023) were associated with shorter telomere length. Ethnicity did not significantly interact with any covariates in determining telomere length, including psychosocial characteristics.
  
  
  CONCLUSIONS
  Black South Africans showed markedly shorter telomeres than did white South African counterparts. Age, male sex, and HIV status were associated with shorter telomere length. No interactions between ethnicity and biomedical or psychosocial factors were found. Ethnic difference in telomere length might primarily be explained by genetic factors.
authors.affiliation: From the Department of Neurology (R.v.K.), Inselspital, Bern University Hospital, and Department of Clinical Research (R.v.K.), University of Bern, Switzerland; Department of Psychosomatic Medicine (R.v.K.), Clinic Barmelweid, Barmelweid, Switzerland; Hypertension in Africa Research Team (HART) (N.T.M., M.H., L.M.), Faculty of Health Sciences, North-West University, Potchefstroom, North-West, South Africa; and Department of Epidemiology and Public Health (M.H.), University College London, London, UK.
authors.forename: Roland
authors.initials: R
authors.lastname: von Känel
authors.forename: Nico T
authors.initials: NT
authors.lastname: Malan
authors.forename: Mark
authors.initials: M
authors.lastname: Hamer
authors.forename: Leoné
authors.initials: L
authors.lastname: Malan
mesh_terms: D000328:Adult; D000368:Aged; D000437:Alcoholism; D044383:Black People; D002097:C-Reactive Protein; D003863:Depression; D050171:Dyslipidemias; D005178:Faculty; D005260:Female; D006442:Glycated Hemoglobin; D015658:HIV Infections; D006801:Humans; D006943:Hyperglycemia; D006973:Hypertension; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009765:Obesity; D012907:Smoking; D013019:South Africa; D013315:Stress, Psychological; D016615:Telomere / Q000378:metabolism*; D059505:Telomere Homeostasis; D044465:White People; D055815:Young Adult
chemical_list: D002097:C-Reactive Protein; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human