title: Fish consumption and frying of fish in relation to type 2 diabetes incidence: a prospective cohort study of Swedish men.
abstract: OBJECTIVE
  Epidemiological evidence on the association between fish consumption and risk of type 2 diabetes is heterogeneous across geographical regions. Differences related to fish consumption pattern could possibly help explain the discrepancy between the findings. We therefore aimed to investigate the association between fish consumption (total, fried, specific fish items) and type 2 diabetes incidence, taking exposure to contaminants present in fish (polychlorinated biphenyls and methyl mercury) into consideration.
  
  
  METHODS
  The population-based Cohort of Swedish Men, including 35,583 men aged 45-79 years, was followed from 1998 to 2012. We estimated hazard ratios (HRs) with 95 % confidence intervals (CIs) using Cox proportional hazards models.
  
  
  RESULTS
  During 15 years of follow-up, 3624 incident cases were identified. Total fish consumption (≥4 servings/week vs. <1 serving/week) was not associated with type 2 diabetes in multivariable-adjusted analysis (HR 1.00; 95 % CI 0.85-1.18); however, a statistically non-significant inverse association was observed after adjustment for dietary contaminant exposures (HR 0.79; 95 % CI 0.60-1.04). Fried fish (≥6 servings/month vs. ≤1 servings/month) and shellfish consumption (≥1 serving/week vs. never/seldom) were associated with HRs of 1.14 (95 % CI 1.03-1.31) and 1.21 (95 % CI 1.07-1.36), respectively.
  
  
  CONCLUSIONS
  We observed no overall association between total fish consumption and type 2 diabetes. The results indicated that dietary contaminants in fish may influence the relationship. Fried fish and shellfish consumption were associated with higher type 2 diabetes incidence. These findings suggest that more specific advice on fish species sub-types (varying in contamination) and preparation methods may be warranted.
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden. alice.wallin@ki.se.
authors.forename: Alice
authors.initials: A
authors.lastname: Wallin
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
authors.forename: Daniela
authors.initials: D
authors.lastname: Di Giuseppe
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
authors.forename: Nicola
authors.initials: N
authors.lastname: Orsini
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
authors.forename: Agneta
authors.initials: A
authors.lastname: Åkesson
authors.affiliation: Medical Research Council Epidemiology Unit, Institute of Metabolic Science, University of Cambridge School of Clinical Medicine, Cambridge, UK.
authors.forename: Nita G
authors.initials: NG
authors.lastname: Forouhi
authors.affiliation: Unit of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Box 210, 171 77, Stockholm, Sweden.
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
mesh_terms: D000368:Aged; D000818:Animals; D015331:Cohort Studies; D003296:Cooking; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000208:ethnology / Q000209:etiology / Q000517:prevention & control*; D000072001:Diet, Healthy / Q000009:adverse effects / Q000208:ethnology; D059305:Diet, High-Fat / Q000009:adverse effects / Q000208:ethnology; D005399:Fishes; D005500:Follow-Up Studies; D005506:Food Contamination; D006801:Humans; D015994:Incidence; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity; D008875:Middle Aged; D010349:Patient Compliance / Q000208:ethnology; D011078:Polychlorinated Biphenyls / Q000633:toxicity; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012042:Registries; D017747:Seafood / Q000009:adverse effects; D012758:Shellfish / Q000009:adverse effects; D013548:Sweden / Q000453:epidemiology; D014873:Water Pollutants / Q000633:toxicity
chemical_list: D008767:Methylmercury Compounds; D014873:Water Pollutants; D011078:Polychlorinated Biphenyls
keywords: Cohort study; Fish; Fried foods; Methyl mercury; Polychlorinated biphenyls; Type 2 diabetes