Fish-seafood consumption, obesity, and risk of type 2 diabetes: an ecological study

There is substantial evidence that type 2 diabetes increases with the degree and duration of obesity. This study was conducted to examine the association, at the international level, between fish and seafood consumption and the prevalence of type 2 diabetes, taking into account the prevalence of obesity.

An ecological study of 41 countries in five continents with different socio-demographic characteristics and sanitary conditions was carried out. Data on the prevalence of diabetes and obesity as well as food balance sheets were collected from websites. Correlations between the variables studied were followed by an exploration of their interaction.

After adjustment for total energy intake, there was a significant correlation (rho=0.81, P<0.0001) between the prevalence of type 2 diabetes in the 20- to 44- and 45- to 64-year age groups. Type 2 diabetes in the 45- to 64-year age group was about 5 times higher than in the 20- to 44-year age group. Obesity was positively associated with type 2 diabetes in both age groups (rho=0.39; P=0.012 and rho=0.48; P=0.002 in the 20- to 44- and 45- to 64-year age groups, respectively). An interaction effect was found between diabetes, obesity and total fish and seafood consumption. In countries with low fish and seafood consumption, the prevalence of type 2 diabetes increased significantly with obesity (0.8 +/- 0.3% vs. 2.5 +/- 1.8%; P=0.002 and 3.3 +/- 2.6% vs. 11.0 +/- 3.9%; P<0.0001 for the 20- to 44- and 45- to 64-year age groups, respectively). In countries with a greater prevalence of obesity, there was evidence of significantly reduced type 2 diabetes with high fish and seafood consumption (2.5 +/- 1.8% vs. 0.9 +/- 0.7%; P=0.007 and 11.0 +/- 3.9% vs. 6.2 +/- 4.1%; P=0.041 for the 20- to 44- and 45- to 64-year age groups, respectively).

The results of this study suggest that high fish and seafood intake may reduce the risk of type 2 diabetes in populations with a high prevalence of obesity.