Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women

PLOS ONE, Dec 2019

Background The effects of fish consumption and n-3 fatty acids on type 2 diabetes mellitus (T2DM) have recently been debated. Objective We explored the risk of T2DM in relation to consumption of lean fish, fatty fish, fish products and total fish as well as cod liver oil supplements in a representative sample of Norwegian women. Design This was a prospective population based cohort study in 33740 women free of T2DM, stroke, angina or heart attack and with detailed information on important co-variates and dietary intake at baseline. Risk ratios and corresponding 95% CI were estimated using Poisson regression with log-person time as offset. Results Lean fish consumption was inversely associated with T2DM compared to zero intake. Risk ratios and 95% CI for intake of 75 and 100 g lean fish per day were 0.71 (0.51, 0.98) and 0.67 (0.46, 0.98), respectively. There was no effect of intake of fatty fish, fish products, total fish or use of cod liver oil supplements on the risk of T2DM. Conclusion Lean fish consumption of 75–100 g/d had a beneficial effect on T2DM. It remains unclear whether lean fish in itself has a protective effect on T2DM or that lean fish consumers have a protective life-style that we were not able to take into account in this study. Unfavorable effects of fatty fish consumption or use of cod liver oil supplements on T2DM were not observed.

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Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women

Lund E (2014) Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women. PLoS ONE 9(2): e89845. doi:10.1371/journal.pone.0089845 Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women Charlotta Rylander 0 Torkjel M. Sandanger 0 Dagrun Engeset 0 Eiliv Lund 0 Yan Gong, College of Pharmacy, University of Florida, United States of America 0 1 Department of Community Medicine, UiT The Arctic University of Norway , Troms, Norway, 2 NILU , Fram- High North Research Centre for Climate and the Environment , Troms , Norway Background: The effects of fish consumption and n-3 fatty acids on type 2 diabetes mellitus (T2DM) have recently been debated. Objective: We explored the risk of T2DM in relation to consumption of lean fish, fatty fish, fish products and total fish as well as cod liver oil supplements in a representative sample of Norwegian women. Design: This was a prospective population based cohort study in 33740 women free of T2DM, stroke, angina or heart attack and with detailed information on important co-variates and dietary intake at baseline. Risk ratios and corresponding 95% CI were estimated using Poisson regression with log-person time as offset. Results: Lean fish consumption was inversely associated with T2DM compared to zero intake. Risk ratios and 95% CI for intake of 75 and 100 g lean fish per day were 0.71 (0.51, 0.98) and 0.67 (0.46, 0.98), respectively. There was no effect of intake of fatty fish, fish products, total fish or use of cod liver oil supplements on the risk of T2DM. Conclusion: Lean fish consumption of 75-100 g/d had a beneficial effect on T2DM. It remains unclear whether lean fish in itself has a protective effect on T2DM or that lean fish consumers have a protective life-style that we were not able to take into account in this study. Unfavorable effects of fatty fish consumption or use of cod liver oil supplements on T2DM were not observed. - Type 2 diabetes mellitus (T2DM) is increasing in epidemic proportions worldwide and is becoming a global health challenge. In 1980, approximately 153 million people had diabetes and by 2008, that number was more than doubled [1]. It has been estimated that the global burden of diabetes will further increase to more than 550 million by 2030 [2], thus, prevention of the disease is of great public health interest. Even though the causes of T2DM are not fully understood, a number of risk factors are well known and include among others: overweight and obesity, family history of diabetes, age, impaired glucose tolerance, sedentary lifestyle, hypertension and history of gestational diabetes. As T2DM is closely linked to overweight and obesity, there has been an increasing focus on the effect of different diets on the prevention and management of T2DM [3]. T2DM and cardiovascular diseases (CVD) have many of the same risk factors in common. Since consumption of fatty fish that contain long chain n-3 fatty acids has showed beneficial effects on the risk of CVD as well as on blood lipids profiles [4], one could expect fish consumption reducing the risk of T2DM as well. Recently, a number of prospective studies have explored associations between fish consumption and risk of T2DM, with conflicting findings [5 8]. One limitation of some of these studies has been the lack of distinction between fatty and lean fish. Several systematic reviews and meta-studies have concluded that there are indications of geographical differences in observed effects of fish consumption, with studies from Asia showing a protective effect whereas studies from North America/Europe indicating an increased risk of T2DM with fish consumption [9,10]. In contrary, a recent nested case-cohort study across eight European countries concluded no effect of total fish consumption on T2DM and indicated a protective effect of fatty fish consumption on the development of T2DM [11]. Fish, and particularly lean fish, is a major part of the Norwegian diet, especially for people living along the Norwegian coastline. Age-adjusted mean intake of total fish was 63 g/day for women residing along in the north or the west coast of Norway [12]. For Table 1. Self-reported baseline characteristics of the total study population (n = 33740), the incident diabetes cases (n = 479) and the non-diabetic subjects (n = 33261). Non-diabetic subjects Total (n = 33740) Diabetes cases (n = 479) (n = 33261) Mean age at enrollment 47.9 Energy intake (kcal/d) Saturated fat (g/d) Years of education (%)b Physical activity (%) Smoking status (%) Alcohol consumption (%) aThe p-value refers to the difference between diabetic and non-diabetic individuals. bMissing information on education, n = 1148. doi:10.1371/journal.pone.0089845.t001 women living in southeast Norway the corresponding number were 42 g/d. Even though there are geographical differences, Norwegia (...truncated)


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Charlotta Rylander, Torkjel M. Sandanger, Dagrun Engeset, Eiliv Lund. Consumption of Lean Fish Reduces the Risk of Type 2 Diabetes Mellitus: A Prospective Population Based Cohort Study of Norwegian Women, PLOS ONE, 2014, 2, DOI: 10.1371/journal.pone.0089845