title: Risk factors for IgA nephropathy: a case-control study with incident cases in Japan.
abstract: OBJECTIVE
  Our previous study with prevalent cases suggested that some genetic, immunological and lifestyle-related factors increased the risk of immunoglobulin A nephropathy (IgAN). To confirm this hypothesis, we conducted another case-control study.
  
  
  METHODS
  The study included 116 incident cases and 276 sex-, age- and residence-matched controls in central Japan. Information on family and individual history and on lifestyle was collected using a self-administered questionnaire. The strength of association between IgAN and a potential risk factor was assessed by calculating an odds ratio.
  
  
  RESULTS
  A family history of chronic glomerulonephritis, susceptibility to the common cold, episodes of tonsillitis in the preceding year, preference for salty foods and a high intake of rice and n-6 polyunsaturated fatty acids (PUFA) were associated with an increased risk of IgAN. Coffee consumption and dietary calcium intake were somewhat negatively related to the risk. A significance of alcohol drinking, use of vitamin supplements, consumption of raw eggs and intake of nutrients other than n-6 PUFA and calcium, though previously suggested, was not shown in the present study.
  
  
  CONCLUSIONS
  Our findings imply that some genetic factors, immune response to infections in the upper respiratory tract and nutritional imbalance would promote the development of IgAN.
authors.affiliation: Department of Preventive Medicine/Biostatistics and Medical Decision Making, Nagoya University Graduate School of Medicine, Nagoya, Japan. wakai@med.nagoya-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakai
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nakai
authors.forename: Seiichi
authors.initials: S
authors.lastname: Matsuo
authors.forename: Takashi
authors.initials: T
authors.lastname: Kawamura
authors.forename: Nigishi
authors.initials: N
authors.lastname: Hotta
authors.forename: Kenji
authors.initials: K
authors.lastname: Maeda
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ohno
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003139:Common Cold; D004032:Diet; D004198:Disease Susceptibility; D005192:Family Health; D005260:Female; D020022:Genetic Predisposition to Disease; D005921:Glomerulonephritis; D005922:Glomerulonephritis, IGA / Q000209:etiology* / Q000235:genetics; D006801:Humans; D007564:Japan; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012307:Risk Factors