title: Low serum free triiodothyronine levels mark familial longevity: the Leiden Longevity Study.
abstract: BACKGROUND
  The hypothalamo-pituitary-thyroid axis has been widely implicated in modulating the aging process. Life extension effects associated with low thyroid hormone levels have been reported in multiple animal models. In human populations, an association was observed between low thyroid function and longevity at old age, but the beneficial effects of low thyroid hormone metabolism at middle age remain elusive.
  
  
  METHODS
  We have compared serum thyroid hormone function parameters in a group of middle-aged offspring of long-living nonagenarian siblings and a control group of their partners, all participants of the Leiden Longevity Study.
  
  
  RESULTS
  When compared with their partners, the group of offspring of nonagenarian siblings showed a trend toward higher serum thyrotropin levels (1.65 vs157 mU/L, p = .11) in conjunction with lower free thyroxine levels (15.0 vs 15.2 pmol/L, p = .045) and lower free triiodothyronine levels (4.08 vs 4.14 pmol/L, p = .024).
  
  
  CONCLUSIONS
  Compared with their partners, the group of offspring of nonagenarian siblings show a lower thyroidal sensitivity to thyrotropin. These findings suggest that the favorable role of low thyroid hormone metabolism on health and longevity in model organism is applicable to humans as well.
authors.affiliation: Department of Gerontology and Geriatrics, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands.
authors.forename: Maarten P
authors.initials: MP
authors.lastname: Rozing
authors.forename: Rudi G J
authors.initials: RG
authors.lastname: Westendorp
authors.forename: Anton J M
authors.initials: AJ
authors.lastname: de Craen
authors.forename: Marijke
authors.initials: M
authors.lastname: Frölich
authors.forename: Bastiaan T
authors.initials: BT
authors.lastname: Heijmans
authors.forename: Marian
authors.initials: M
authors.lastname: Beekman
authors.forename: Carolien
authors.initials: C
authors.lastname: Wijsman
authors.forename: Simon P
authors.initials: SP
authors.lastname: Mooijaart
authors.forename: Gerard-Jan
authors.initials: GJ
authors.lastname: Blauw
authors.forename: P Eline
authors.initials: PE
authors.lastname: Slagboom
authors.forename: Diana
authors.initials: D
authors.lastname: van Heemst
mesh_terms: D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008136:Longevity / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D013972:Thyrotropin / Q000097:blood; D014284:Triiodothyronine / Q000097:blood*
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin