title: Longevity-associated mitochondrial DNA 5178 C/A polymorphism modulates the effects of coffee consumption on erythrocytic parameters in Japanese men: an exploratory cross-sectional analysis.
abstract: BACKGROUND
  Mitochondrial DNA 5178 cytosine/adenine (Mt5178 C/A) polymorphism reportedly modulates the effects of coffee consumption on the risk of hypertension, dyslipidemia and abnormal glucose tolerance. The objective of this analysis was to investigate whether Mt5178 C/A polymorphism modifies the effects of coffee consumption on erythrocytic parameters in male Japanese health check-up examinees.
  
  
  METHODS
  A total of 436 men (mean age ± standard deviation, 54.1 ± 7.8 years) were selected from among individuals visiting the hospital for regular medical check-ups. After Mt5178 C/A genotyping, an exploratory cross-sectional analysis assessing the joint effects of Mt5178 C/A polymorphism and coffee consumption on red blood cell counts, hematocrit and hemoglobin was conducted.
  
  
  RESULTS
  For Mt5178C genotypic men, after adjustment for age, body mass index, alcohol consumption, habitual smoking and green tea consumption, coffee consumption significantly decreased red blood cell counts (P for trend = 0.022) and hemoglobin (P for trend = 0.035). The risk of anemia, defined as hemoglobin of <14 g/dL, after the aforementioned adjustment, appeared to depend on coffee consumption (P for trend = 0.078), and the adjusted odds ratio for anemia was significantly higher in men who consumed ≥4 cups of coffee per day than in those who consumed <1 cup per day (odds ratio = 3.771, 95% confidence interval: 1.088 to 13.06, P = 0.036). For Mt5178A genotypic men, coffee consumption possibly reduced the risk of anemia (P for trend = 0.049). However, after the aforementioned adjustment, the statistical significance disappeared (P for trend = 0.137).
  
  
  CONCLUSIONS
  This exploratory cross-sectional analysis suggests that Mt5178 C/A polymorphism modulates the effects of coffee consumption on erythrocytic parameters and the risk of anemia in male Japanese health check-up examinees.
authors.affiliation: Department of Public Health, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. akokaze@med.showa-u.ac.jp.
authors.forename: Akatsuki
authors.initials: A
authors.lastname: Kokaze
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Naomi
authors.initials: N
authors.lastname: Matsunaga
authors.forename: Kanae
authors.initials: K
authors.lastname: Karita
authors.forename: Masao
authors.initials: M
authors.lastname: Yoshida
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Ohtsu
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ochiai
authors.forename: Takako
authors.initials: T
authors.lastname: Shirasawa
authors.forename: Hinako
authors.initials: H
authors.lastname: Nanri
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Saga
authors.forename: Iichiro
authors.initials: I
authors.lastname: Ohtsu
authors.forename: Hiromi
authors.initials: H
authors.lastname: Hoshino
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takashima
mesh_terms: D044466:Asian People / Q000235:genetics*; D003069:Coffee; D003430:Cross-Sectional Studies; D004272:DNA, Mitochondrial / Q000235:genetics*; D004909:Erythrocyte Indices / Q000235:genetics*; D005247:Feeding Behavior / Q000502:physiology*; D006801:Humans; D007564:Japan; D008136:Longevity; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic / Q000235:genetics*
chemical_list: D003069:Coffee; D004272:DNA, Mitochondrial