title: Risk Factors for Sporadic Domestically Acquired Campylobacter Infections in Norway 2010-2011: A National Prospective Case-Control Study.
abstract: BACKGROUND
  Campylobacteriosis is the most frequently reported food- and waterborne infection in Norway. We investigated the risk factors for sporadic Campylobacter infections in Norway in order to identify areas where control and prevention measures could be improved.
  
  
  METHODS
  A national prospective case-control study of factors associated with Campylobacter infection was conducted from July 2010 to September 2011. Cases were recruited from the Norwegian Surveillance System of Communicable Diseases (MSIS). Controls were randomly selected from the Norwegian Population Registry. Cases and controls were mailed a paper questionnaire with a prepaid return envelope. Univariable analyses using logistic regression were conducted for all exposures. A final parsimonious multivariable model was developed using regularized/penalized logistic regression, and adjusted odds ratios were calculated.
  
  
  RESULTS
  A total of 995 cases and 1501 controls were included in the study (response proportion 55% and 30%, respectively). Exposures that had significant increases in odds of Campylobacter infection in multivariable analysis were drinking water directly from river, stream, or lake (OR: 2.96), drinking purchased bottled water (OR: 1.78), eating chicken (1.69), eating meat that was undercooked (OR: 1.77), eating food made on a barbecue (OR: 1.55), living on a farm with livestock (OR: 1.74), having a dog in the household (OR: 1.39), and having household water supply serving fewer than 20 houses (OR: 1.92).
  
  
  CONCLUSIONS
  Consumption of poultry and untreated water remain important sources of Campylobacter infection in Norway, despite ongoing control efforts. The results justify the need for strengthening education for consumers and food handlers about the risks of cross-contamination when preparing poultry and with consuming raw or undercooked chicken. The public should also be reminded to take precautions when drinking untreated water in nature and ensure continued vigilance in order to protect and maintain the quality of water from small-scale water supply systems.
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control, Stockholm, Sweden.
authors.forename: Emily
authors.initials: E
authors.lastname: MacDonald
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway; Department of Health Statistics, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Richard
authors.initials: R
authors.lastname: White
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control, Stockholm, Sweden.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Mexia
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Tone
authors.initials: T
authors.lastname: Bruun
authors.affiliation: Division of Infection Control, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Georg
authors.initials: G
authors.lastname: Kapperud
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control, Stockholm, Sweden.
authors.forename: Heidi
authors.initials: H
authors.lastname: Lange
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Karin
authors.initials: K
authors.lastname: Nygård
authors.affiliation: Department of Infectious Disease Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Line
authors.initials: L
authors.lastname: Vold
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002169:Campylobacter Infections / Q000453:epidemiology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009664:Norway; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult