Background
The relationship between dietary habits and development of chronic kidney disease (CKD) is uncertain. This retrospective cohort study was conducted to examine the association between unhealthy dietary habits and proteinuria onset, a key prognostic factor of CKD.
Methods
We conducted a retrospective cohort study among individuals in a Japanese general population aged ≥ 40 years who underwent annual medical checkups from 1998 to 2014 in Kanazawa City, Japan. The risks of proteinuria onset were estimated based on the status of baseline unhealthy dietary habits (quick eating, late dinner, late evening snack, and skipping breakfast) compared with the status without these habits. We calculated the incidence rates per 1000 person-years based on the presence or absence of each unhealthy dietary habit. Multivariable Cox proportional hazards models were used to estimate the risks of proteinuria onset based on baseline unhealthy dietary habits. Changes in body mass index (BMI) and waist-to-height ratio (WHtR), which were possible intermediate factors in unhealthy dietary habits and proteinuria onset, were estimated using a linear mixed-effects model with random intercept and random slope.
Results
A total of 26,764 subjects were included, with a mean follow-up period of 3.4 years. The most frequent unhealthy dietary habits were quick eating (29%), followed by late dinner (19%), late evening snack (16%), and skipping breakfast (9%). During the follow-up period, 10.6% of the participants developed proteinuria, with an incidence rate of 32.7 per 1000 person-years. Late dinner or skipping breakfast had an increased adjusted risk of proteinuria onset (hazard ratio [HR] 1.12, 95% confidence interval [CI] 1.02 to 1.22, and HR 1.15, 95% CI 1.01 to 1.31, respectively). Each unhealthy dietary habit was not associated with changes in BMI or WHtR.
Conclusion
Our results suggest that late dinner and skipping breakfast were associated with higher risks for proteinuria onset. Unhealthy dietary habits were not associated with changes in BMI or WHtR during the follow-up period.