The interplay between uric acid and antioxidants in relation to physical function in older persons.
OBJECTIVE
To investigate the relationship between circulating uric acid (UA) levels and plasma antioxidants and whether antioxidant levels modulate the association between UA and physical function.


METHODS
Cross-sectional.


METHODS
Community-based.


METHODS
Nine hundred sixty-six elderly persons participating in the baseline assessment of the Invecchiare in Chianti Study.


METHODS
UA, carotenoid, tocopherol, and selenium concentrations were assayed. Physical function was measured using the Short Physical Performance Battery (SPPB) and difficulties in instrumental activities of daily living (IADLs). Potential confounders were assessed using standardized methods.


RESULTS
Total carotenoids (P=.008), in particular alpha-carotene (P=.02), lutein (P<.001), zeaxanthin (P<.001), lycopene (P=.07), cryptoxanthin (P=.29), and selenium (P=.04) were inversely associated with UA levels. Total tocopherols (P=.06) and alpha-tocopherol (P=.10) had a positive trend across UA levels. SPPB (P=.01) and IADL disability (P=.002) were nonlinearly distributed across the UA quintiles. Participants within the middle UA quintile (4.8-5.3 mg/dL) were less disabled in IADLs and had better SPPB scores than those in the extreme UA quintiles. There was a significant interaction between UA and selenium in the model predicting SPPB score (P=.02).


CONCLUSIONS
UA levels are inversely associated with circulating carotenoids and selenium. Participants with intermediate UA levels had a higher prevalence of good physical functions, higher SPPB scores, and lower IADL disability. This study suggests that older subjects with intermediate UA levels may have an optimum balance between proinflammatory and antioxidant compounds that may contribute to better physical performance.
Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21225, USA.
Carmelinda
C
Ruggiero
Antonio
A
Cherubini
Jack
J
Guralnik
Richard D
RD
Semba
Marcello
M
Maggio
Shari M
SM
Ling
Fulvio
F
Lauretani
Stefania
S
Bandinelli
Umberto
U
Senin
Luigi
L
Ferrucci
D000203:Activities of Daily Living; D000368:Aged; D000975:Antioxidants / Q000032:analysis*; D002338:Carotenoids / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D012643:Selenium / Q000097:blood*; D024505:Tocopherols / Q000097:blood*; D014527:Uric Acid / Q000097:blood*
D000975:Antioxidants; D014527:Uric Acid; D002338:Carotenoids; D012643:Selenium; D024505:Tocopherols