Telomeres and the natural lifespan limit in humans. Author: Steenstrup T1, Kark JD2, Verhulst S3, Thinggaard M4,5, Hjelmborg JV1,6, DalgÄrd C7, Kyvik KO8, Christiansen L1,5,6, Mangino M9,10, Spector TD9, Petersen I1, Kimura M11, Benetos A12,13,14, Labat C13,14, Sinnreich R2, Hwang SJ15, Levy D15, Hunt SC16, Fitzpatrick AL17, Chen W18, Berenson GS18, Barbieri M19, Paolisso G19, Gadalla SM20, Savage SA20, Christensen K4,5,6, Yashin AI21, Arbeev KG21, Aviv A11 Affiliation: <sup>1</sup>Epidemiology, Biostatistics and Biodemography, Institute of Public Health, University of Southern Denmark, Odense 5000, Denmark. <sup>2</sup>Epidemiology Unit, Hebrew University-Hadassah School of Public Health and Community Medicine, Jerusalem 91120, Israel. <sup>3</sup>Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands. <sup>4</sup>Department of Clinical Genetics, Odense University Hospital, Odense 5220, Denmark. <sup>5</sup>Danish Aging Research Center, University of Southern Denmark, Odense 5000, Denmark. <sup>6</sup>The Danish Twin Registry, University of Southern Denmark, Odense 5220, Denmark. <sup>7</sup>Department of Public Health, Environmental Medicine, University of Southern Denmark, 5000 Odense C, Denmark. <sup>8</sup>Department of Clinical Research, University of Southern Denmark and Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Odense, Denmark. <sup>9</sup>Department of Twin Research and Genetic Epidemiology, King's College London, London, UK. <sup>10</sup>NIHI Biomedical Research Center at Guy's and St Thomas Foundation Trust, London SE1 9RT, UK. <sup>11</sup>Center of Human Development and Aging, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA. <sup>12</sup>Department of Geriatrics, University Hospital of Nancy, F54500, France. <sup>13</sup>INSERM, U1116, Vandoeuvre-les-Nancy, F54500, France. <sup>14</sup>Université de Lorraine, Nancy, F54000, France. <sup>15</sup>Population Sciences Branch of the National Heart, Lung and Blood Institute, Bethesda, MD and the Framingham Heart Study, Framingham, MA 01702, USA. <sup>16</sup>Cardiovascular Genetics Division, Department of Medicine, Cornell University, Ithaca, NY 14850 USA. <sup>17</sup>Department of Epidemiology, University of Washington, Seattle, WA 98195, USA. <sup>18</sup>Center for Cardiovascular Health, Tulane University, New Orleans, LA 07118, USA. <sup>19</sup>Department of Medical, Surgery, Neurologic, Metabolic and Aging Science, University of Campania "Luigi Vanvtelli" 80138 Naples, Italy. <sup>20</sup>Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20890, USA. <sup>21</sup>Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC 27708, USA. Conference/Journal: Aging (Albany NY). Date published: 2017 Apr 6 Other: Special Notes: doi: 10.18632/aging.101216. [Epub ahead of print] , Word Count: 118 An ongoing debate in demography has focused on whether the human lifespan has a maximal natural limit. Taking a mechanistic perspective, and knowing that short telomeres are associated with diminished longevity, we examined whether telomere length dynamics during adult life could set a maximal natural lifespan limit. We define leukocyte telomere length of 5 kb as the 'telomeric brink', which denotes a high risk of imminent death. We show that a subset of adults may reach the telomeric brink within the current life expectancy and more so for a 100-year life expectancy. Thus, secular trends in life expectancy should confront a biological limit due to crossing the telomeric brink. KEYWORDS: leukocytes; life-expectancy; longevity; maximal lifespan; sex PMID: 28394764 DOI: 10.18632/aging.101216