Association between coffee consumption and the estimated glomerular filtration rate in the general Japanese population: preliminary data regarding C-reactive protein concentrations.
BACKGROUND
Cardiometabolic disorders including cardiovascular disease (CVD) where the relevance of regular coffee consumption is debatable, has been linked with the development of chronic kidney disease (CKD). A more recent study suggests that coffee consumption is associated with normal or increased kidney function as assessed by the estimated glomerular filtration rate (eGFR). The present study investigated whether the association between coffee and the eGFR was independent of chronic inflammation, and whether adding sugar to coffee could affect the eGFR.


METHODS
A total of 114 age- and gender-matched Japanese individuals (females/males=68/46, mean age=59.5 years), without CVD and severe CKD, were studied. Clinical variables, such as body mass index, blood pressure, blood glucose, lipids and high-sensitivity C-reactive protein (hsCRP), in addition to eGFR [the Modification of Diet in Renal Disease (MDRD) study equation], were measured.


RESULTS
Coffee drinkers had higher eGFR values [73.9±16.5 (SD) mL/min/1.73 m(2)] than non-coffee drinkers (68.6±11.7). The difference remained significant (F=5.04, p=0.027), independently of clinical variables, including hsCRP. The eGFR values among coffee drinkers were similar between the subjects with and without use of sugar.


CONCLUSIONS
The association of coffee drinking habits to eGFR may occur independently of inflammation as assessed by hsCRP. The use of sugar may have no effect on GFR. Further research is needed to clarify this phenomenon.
Kotani
Kazuhiko
K
Division of Preventive Medicine, Clinical Research Institute, National Hospital Organization Kyoto Medical Center, Kyoto, Japan. kazukotani@jichi.ac.jp
Sakane
Naoki
N
Yamada
Toshiyuki
T
Taniguchi
Nobuyuki
N
D002097:C-Reactive Protein / Q000032:analysis*; D003069:Coffee / Q000009:adverse effects*; D005247:Feeding Behavior; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007249:Inflammation; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D013395:Sucrose / Q000494:pharmacology
D003069:Coffee; D013395:Sucrose; D002097:C-Reactive Protein