Serum levels of retinol and other antioxidants for hearing impairment among Japanese older adults.
BACKGROUND
The objective of this study was to assess the relation between serum levels of retinol and other antioxidants and hearing impairment in Japanese older adults.


METHODS
This is a community-based cross-sectional study comprising 762 residents aged 65 years or older in Kurabuchi, Gumma, Japan. We measured serum retinol and other antioxidants (alpha- and gamma-tocopherols, and carotenoids including beta-cryptoxanthin, alpha- and beta-carotenes, lycopene, and lutein plus zeaxanthin) by high-performance liquid chromatography and divided each measurement into quartiles. Hearing impairment was defined as a failure to hear a 30-dB hearing level (HL) signal at 1 kHz and a 40-dB HL signal at 4 kHz in the better ear in pure-tone audiometric tests. The odds ratios (OR) for hearing impairment were calculated for each of the upper three quartiles of retinol and other antioxidant levels relative to the lowest quartile.


RESULTS
Crude analysis showed that serum levels of retinol and provitamin A carotenoids (beta-cryptoxanthin, and alpha- and beta-carotenes) were inversely related to the prevalence of hearing impairment. The multiadjusted ORs (95% confidence intervals) for the highest quartile of retinol and the provitamin A family (combinations of provitamin A carotenoids) compared with the lowest were 0.51 (0.26-1.00) and 0.53 (0.27-1.02), respectively. A dose-response relationship was observed for retinol (p = .03) and provitamin A (p = .09).


CONCLUSIONS
Increased serum levels of retinol and provitamin A carotenoids were clearly associated with a decreased prevalence of hearing impairment.
DMSc, Department of Preventive Medicine and Public Health, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Takehiro
T
Michikawa
Yuji
Y
Nishiwaki
Yuriko
Y
Kikuchi
Kanae
K
Hosoda
Kunio
K
Mizutari
Hideyuki
H
Saito
Keiko
K
Asakura
Ai
A
Milojevic
Satoko
S
Iwasawa
Makiko
M
Nakano
Toru
T
Takebayashi
D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000032:analysis*; D002338:Carotenoids / Q000097:blood*; D005260:Female; D034381:Hearing Loss / Q000097:blood* / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence; D024505:Tocopherols / Q000097:blood*; D014801:Vitamin A / Q000097:blood*
D000975:Antioxidants; D014801:Vitamin A; D002338:Carotenoids; D024505:Tocopherols