Long-term fish intake preserves kidney function in elderly individuals: the Ikaria study.

Objectives: The aim of this work was to evaluate the correlation between the amount of weekly fish intake and kidney function as measured by creatinine clearance (CCr) rate among elderly inhabitants of Ikaria Island, a place that has been related to an increased rate of longevity.

Methods: From June to October of 2009, 673 males and females, aged 65-100 years and long-term residents of Ikaria Island were enrolled. Of those, 328 (75 ± 7 years) were males and 339 (75 ± 6 years) were females. Nutritional habits, including fish intake, were evaluated using a validated, semi-frequent food questionnaire and the MedDietScore. Urea and creatinine were measured, and CCr rate was estimated by the Cockcroft-Gault formula.

Results: Eighty-four percent of participants reported fish consumption of more than 150 g/week; 35% had moderate to severe CCr (<60 mL). Crude analysis revealed that CCr rate was positively associated with fish intake (b ± SE per 100 g/day: 24 ± 9, P = .007); multiple linear regression analysis confirmed the previous finding (b ± SE per 100 g/day: 11 ± 2, P = .001) after adjusting for overall dietary habits through the MedDietScore and other potential confounders. Fish intake was positively associated with CCr. Furthermore, multi-adjusted logistic regression analysis showed that fish consumption of 100 g/day increased the likelihood by 121% of having a CCr greater than 60 mL (95% confidence interval 10%-343%).

Conclusions: Long-term fish consumption was independently associated with improved kidney function among elderly individuals, a finding that extends the current knowledge regarding the benefits of fish intake on human health.