Association of thyroid dysfunction with vitamin B12, folate and plasma homocysteine levels in the elderly: a population-based study in Sicily.
BACKGROUND
Association of thyroid dysfunction with plasma homocysteine levels and vitamin B(12) has previously been reported. We evaluated these associations in the elderly in San Teodoro, a mountainous village of Sicily.


METHODS
Subjects (n=279) aged 60-85 years (119 males and 160 females) were examined using self-reported signs, clinical examination and laboratory tests.


RESULTS
Hypothyroidism and/or goiter were two characteristics that were not associated with a significant change in homocysteine when compared with euthyroidism and the absence of goiter. Vitamin B(12) was significantly higher in subjects in the first quartile of the thyroid-stimulating hormone distribution, compared with those in the fourth quartile (371+/-207 vs. 297+/-196 pmol/L, p=0.0121). Homocysteine was significantly higher in the first quartile of the free tri-iodothyronine distribution compared to the third quartile (18.0+/-5.7 vs. 16.0+/-6.2 micromol/L, p=0.0130) and was correlated with log tri-iodothyronine in euthyroid subjects (p=0.0254). In multivariate analysis, homocysteine was associated with vitamin B(12) (p=0.0014), folate (p<0.0001), creatinine (p<0.0001) and age (p<0.0001), but not with either free tri-iodothyronine (p=0.7680), tetra-iodothyronine (p=0.5706) or thyroid-stimulating hormone (p=0.2294).


CONCLUSIONS
Our results suggest that the influence of thyroid hormones on homocysteine is much weaker in elderly subjects than in selected patients with hypothyroidism.
Stella
Giuseppe
G
Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Troina (EN), Italy.
Spada
Rosario Sebastiano
RS
Calabrese
Santa
S
Bosco
Paolo
P
Anello
Guido
G
Guéant-Rodriguez
Rosa-Maria
RM
Romano
Antonino
A
Benamghar
Lahoucine
L
Proto
Caterina
C
Castellano
Antonino
A
Fajardo
Adrian
A
Lipari
Lina
L
Sirna
Salvatore
S
Guéant
Jean-Louis
JL
D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000473:pathology*; D004813:Epidemiology; D005260:Female; D005492:Folic Acid / Q000097:blood*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012802:Sicily / Q000453:epidemiology; D013959:Thyroid Diseases / Q000097:blood / Q000453:epidemiology*; D014805:Vitamin B 12 / Q000097:blood*
D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12