We have previously shown that individuals in Ashkenazi families with exceptional longevity have generally been spared major age-related diseases such as cardiovascular disease and diabetes mellitus, which are largely responsible for mortality in the elderly, and that these features are heritable (23). Because studies on individuals with a normal life span suggest that

Telomere length varies among individuals and families and follows the polygenic mode of inheritance pattern typical of most

– ciated with shorter telomeres (24 28), we assessed the telomere length in blood leukocytes among subjects with exceptional longevity (centenarians) to investigate if centenarians survived with long telomeres, an indicator of better telomere length fl maintenance, or short telomeres re ecting chronologically old age. In addition, in view of a strong family history of excep- tional longevity and genetic basis of telomere length main- tenance, we tested if telomere length as a trait would be inherited by the offspring of centenarians and associated with the status of aging-related diseases. Finally, to study the genetic basis of telomere length maintenance, we took a candidate gene approach to discover all possible variations in two main hTERT genes associated with telomerase enzyme activity, and hTERC , in centenarians and younger controls for genetic as- sociation analysis with human exceptional longevity and telo- mere length. Our overall hypothesis is that maintenance of telomere length may indicate generalized genomic integrity, fl which, in turn, may have a profound in uence on health and aging in humans.

fvItallO15 <6566-75 76-85 86-95Age (Year) 96-105

Results

Telomere Length, Heritability, and Longevity. Phenotypes of tenarians, their offspring (approximate age of 70 years), offspring-matched controls without a family history of longevity, all of Ashkenazi Jewish descent, are presented Table 1. The control and offspring groups have similar fi teristics of lipid pro les, except that controls have a smaller percentage of large LDL particle size, but these fi ences are not signi cant (Table 1). The centenarian group plays a lower mean body mass index and higher HDL levels compared with controls (Table 1).

Fig. 1. Comparison of telomere length among Ashkenazi Jewish cen- tenarians (n = 86), their offspring (n = 175), and controls (n = 93). Values are adjusted for age at recruitment and gender in the offspring and control groups and for gender alone in the centenarian group. *P < 0.05.

intrafamily correlation, we used a sandwich variance estimator equation and a generalized estimating equation (GEE), re- fi spectively. Both analyses repeated our rst estimation supporting fi the observation of signi cant telomere length differences between – offspring and controls, on average, by 0.081 (95% CI: 0.022 0.139; P = 0.007) for the sandwich estimation and by 0.082 (95% CI: – P 0.017 0.147; = 0.013) for the GEE. Moreover, unlike controls, offspring of centenarians do not show an appreciable decline in telomere length with age as compared with controls (Fig. 1). However, the difference in age-related decline did not differ sig- fi ni cantly between offspring and controls (adjusted mean differ- − P ence = 0.002, 95% CI: 0.007 to +0.010; = 0.682) by the same hierarchical linear model described earlier. High heritability P (86%; = 0.005) for telomere length between centenarians and their offspring was observed, suggesting that telomere length has a strong genetic component in families with exceptional longevity

When controls and centenarians are combined to represent cross-sectional age groups of unrelated individuals from middle – age to oldest old (range: 43 105 years), telomere length declines with age until the age of 85 years (Fig. 1). However, individuals older than 86 years of age as well as the centenarians show longer telomere lengths compared with unrelated individuals younger P than 85 years of age, with a mean difference of 0.17 ( = 0.04) in the linear regression model adjusting for age and gender. The telomere length of offspring exceeds that of controls in a hier- fi archical linear model, on average by 0.082 [95% con dence in- terval (CI): 0.017– 0.148; P = 0.014]. Because centenarians and their offspring are appreciable singleton families, we used the re- gression approach for nonindependencies of the observed sub- jects. To account for parametric model bias as well as for unknown

Table 1. Phenotypic characteristics of study subjects for telomere length measurements

Controls Offspring Centenarians Offspring vs. Centenarians vs. (n = 93) (n = 175) (n = 86) controls controls Age range, years 43–94 (71.8) 44–85 (67.8) 95–105 (97.4) 0.0001 0.0001 Female, % 55 36 63 0.001 0.24 Body mass index, kg/m2 25 (0.4) 26 (0.3) 22 (0.4) 0.28 0.0001 Waist circumference, inch 34 (0.4) 35 (0.3) 35 (0.5) 0.22 0.57 Cholesterol, mg/dL 197 (3.8) 202 (2.9) 191 (4) 0.28 0.26 Triglyceride, mg/dL 154 (8.9) 146 (6.7) 151 (9.6) 0.52 0.81 LDL, mg/dL 107 (3.5) 112 (2.6) 106 (3.6) 0.22 0.76 HDL, mg/dL 58 (1.7) 61 (1.3) 51 (1.8) 0.21 0.003 LDL particle size, nm 20.9 (0.12) 21.1 (0.08) 21.2 (0.1) 0.29 0.06 HDL particle size, nm 9.23 (0.07) 9.15 (0.05) 9.36 (0.06) 0.37 0.17 Large LDL particle size, % of total 52 (4.4) 62 (3.0) 62 (3.9) 0.07 0.1 Large HDL particle size, % of total 53 (2.3) 50 (1.6) 55 (2.1) 0.26 0.42

The phenotypic characteristics were adjusted for age and gender when controls were compared with offspring and for gender when controls were compared with centenarians. All values are mean (SE).