Genetic influence on human lifespan and longevity

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Hum Genet. 2006 Feb 4;:1-10 [Epub ahead of print]

Genetic influence on human lifespan and longevity.

Hjelmborg JV, Iachine I, Skytthe A, Vaupel JW, McGue

M, Koskenvuo M, Kaprio J, Pedersen NL, Christensen K.

Institute of Public Health, University of Southern

Denmark, J. B. Winslovsvej 9 B, 5000, Odense C,

Denmark, jhjelmborg@....

There is an intense search for longevity genes in both

animal models and humans. Human family studies have

indicated that a modest amount of the overall

variation in adult lifespan (approximately 20-30%) is

accounted for by genetic factors. But it is not known

if genetic factors become increasingly important for

survival at the oldest ages. We study the genetic

influence on human lifespan and how it varies with age

using the almost extinct cohorts of Danish, Finnish

and Swedish twins born between 1870 and 1910

comprising 20,502 individuals followed until

2003-2004. We first estimate mean lifespan of twins by

lifespan of co-twin and then turn to the relative

recurrence risk of surviving to a given age. Mean

lifespan for male monozygotic (MZ) twins increases

0.39 [95% CI (0.28, 0.50)] years for every year his

co-twin survives past age 60 years. This rate is

significantly greater than the rate of 0.21 (0.11,

0.30) for dizygotic (DZ) males. Females and males have

similar rates and these are negligible before age 60

for both MZ and DZ pairs. We moreover find that having

a co-twin surviving to old ages substantially and

significantly increases the chance of reaching the

same old age and this chance is higher for MZ than for

DZ twins. The relative recurrence risk of reaching age

92 is 4.8 (2.2, 7.5) for MZ males, which is

significantly greater than the 1.8 (0.10, 3.4) for DZ

males. The patterns for females and males are very

similar, but with a shift of the female pattern with

age that corresponds to the better female survival.

Similar results arise when considering only those

Nordic twins that survived past 75 years of age. The

present large population based study shows genetic

influence on human lifespan. While the estimated

overall strength of genetic influence is compatible

with previous studies, we find that genetic influences

on lifespan are minimal prior to age 60 but increase

thereafter. These findings provide a support for the

search for genes affecting longevity in humans,

especially at advanced ages.

PMID: 16463022 [PubMed - as supplied by publisher]

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