An association between serum γ-glutamyltransferase and proteinuria in drinkers and non-drinkers: a Japanese nationwide cross-sectional survey.
BACKGROUND
The association between alcohol consumption and chronic kidney disease (CKD), characterized by reduced glomerular filtration rate and proteinuria, is controversial. Recent studies suggest that serum γ-glutamyltransferase (GGT) level, a conventional marker of excessive alcohol consumption, predicts the CKD incidence. Little information is available on the difference in the clinical impact of alcohol consumption and GGT on proteinuria.


METHODS
The present cross-sectional survey included 332,296 Japanese people aged ≥40 years in 2008. To examine the associations of GGT and alcohol consumption with proteinuria, 134,600 men and 197,696 women were classified into 20 categories based on GGT quartiles and alcohol consumption categories, and their prevalence rate ratios (PRR) of proteinuria defined as ≥1+ of dipstick urinary protein were calculated after adjusting for clinically relevant factors.


RESULTS
Prevalence of proteinuria was 7.5 and 3.7 % in men and women, respectively. In both gender an association between alcohol consumption and proteinuria was in a J-shaped fashion with the lowest PRR of mild drinkers with ≤19 g/day of ethanol consumption, whereas an association between serum GGT level and proteinuria was linear. Compared with rare drinkers in the lowest GGT quartile, the subjects in higher GGT quartiles had a higher probability of proteinuria, irrespective of alcohol consumption. An optimal cutoff level of serum GGT was 43.6 and 23.2 IU/L in men and women, respectively.


CONCLUSIONS
The subjects with higher serum GGT level had a higher probability of proteinuria, regardless of alcohol consumption, suggesting that GGT has a clinically greater impact on CKD than alcohol consumption.
Department of Geriatric Medicine and Nephrology, Osaka University Graduate School of Medicine, 2-2-B6 Yamadaoka, Suita, 565-0871, Japan.
Toshihiro
T
Ishigami
Ryohei
R
Yamamoto
Yasuyuki
Y
Nagasawa
Yoshitaka
Y
Isaka
Hiromi
H
Rakugi
Kunitoshi
K
Iseki
Kunihiro
K
Yamagata
Kazuhiko
K
Tsuruya
Hideaki
H
Yoshida
Shouichi
S
Fujimoto
Koichi
K
Asahi
Issei
I
Kurahashi
Yasuo
Y
Ohashi
Toshiki
T
Moriyama
Tsuyoshi
T
Watanabe
D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects / Q000097:blood* / Q000453:epidemiology*; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011507:Proteinuria / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D012307:Risk Factors; D005723:gamma-Glutamyltransferase / Q000097:blood*
D015415:Biomarkers; D005723:gamma-Glutamyltransferase