25(OH)D Serum levels decline with age earlier in women than in men and less efficiently prevent compensatory hyperparathyroidism in older adults.
BACKGROUND
Although a host of factors are known to influence 25-hydroxyvitamin D [25(OH)D] serum levels, few studies addressed the distinctive sex-specific influence of aging, and the age-specific relationship of parathyroid hormone (PTH) with 25(OH)D. The aims of this research were to evaluate changes of 25(OH)D and PTH levels with age in a large population-based sample of men and women and to test the hypothesis that 25(OH)D serum concentrations needed to offset age-associated hyperparathyroidism are significantly higher in older than in younger persons.


METHODS
In 1107 participants of the InCHIANTI (Invecchiare in Chianti, i.e., Aging in the Chianti area) study, we collected information on dietary intake, daylight exposure, and disability, and measured renal function and serum 25(OH)D and PTH.


RESULTS
In women, the age-related decline of 25(OH)D was already evident shortly after age 50, whereas in men it started only after age 70 and was substantially less steep. Age, daylight exposure, winter season, and disability were independent predictors of low 25(OH)D levels. For any given level of 25(OH)D, PTH levels were progressively and consistently higher in older than in younger participants.


CONCLUSIONS
These findings suggest that the age-associated fall of serum 25(OH)D starts earlier in women than in men and that higher levels of 25(OH)D are required in older compared to younger persons to avoid the age-associated compensatory hyperparathyroidism.
Maggio
Dario
D
Gerontology and Geriatrics, University of Perugia, Policlinico Monteluce, Via Brunamonti, 06122 Perugia, Italy. dariomaggio1@tin.it
Cherubini
Antonio
A
Lauretani
Fulvio
F
Russo
Roberto Cosimo
RC
Bartali
Benedetta
B
Pierandrei
Marco
M
Ruggiero
Carmelinda
C
Macchiarulo
Maria Carmela
MC
Giorgino
Ruben
R
Minisola
Salvatore
S
Ferrucci
Luigi
L
D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000517:prevention & control*; D008297:Male; D012680:Sensitivity and Specificity; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D014807:Vitamin D; C104450:25-hydroxyvitamin D