Randomized controlled trials suggest that protein restriction may retard the progression of CKD toward ESRD. However, the effects of dietary protein intake level and the food sources of dietary protein on the risk of ESRD in the general population remain unclear. We investigated these effects in the Singapore Chinese Health Study, a prospective population-based cohort that recruited 63,257 Chinese adults aged 45-74 years from 1993 to 1998. We collected habitual diet information via a validated semiquantitative food frequency questionnaire and identified ESRD via record linkage with a nationwide registry. In all, 951 cases of ESRD occurred over a mean follow-up of 15.5 years. Regarding total protein intake, compared with the lowest quartile, the three higher quartiles combined had a hazard ratio for ESRD of 1.24 (95% confidence interval [95% CI], 1.05 to 1.46), but the dose-dependent association across the quartiles was not statistically significant (P trend =0.16). Red meat intake strongly associated with ESRD risk in a dosedependent manner (hazard ratio for highest quartile versus lowest quartile,1.40 [95% CI, 1.15 to 1.71; P trend ,0.001]). Intake of poultry, fish, eggs, or dairy products did not associate with risk of ESRD. In substitution analysis, replacing one serving of red meat with other food sources of protein associated with a maximum relative risk reduction of 62.4% (95% CI, 33.1 to 78.9; P,0.01). Our study shows that red meat intake may increase the risk of ESRD in the general population and substituting alternative sources of protein may reduce the incidence of ESRD.

Background: Cross-sectional studies suggest that coffee drinking is associated with better renal function. However, to our knowledge, no prospective study has examined its relation with the risk of end-stage renal disease (ESRD). Objective: We examined the relations between coffee, tea, soda, and total caffeine consumption and the risk of ESRD among middle-aged and older Chinese in Singapore. Methods: We used data from the Singapore Chinese Health Study, a prospective cohort of 63,257 men and women aged 45-74 y at recruitment from 1993 to 1998. Baseline information on the consumption of caffeinated coffee and other caffeinated beverages (tea and sodas), habitual diet, medical history, and lifestyle factors was obtained via in-person interviews. The standard serving size of 1 cup was assigned as 237 mL in the questionnaire. Incident ESRD cases were identified via linkage with the nationwide registry. We used multivariable Cox regression models to estimate HRs and 95% CIs of ESRD risk associated with the consumption of caffeinated beverages, with adjustment for potential confounders. Results: After a mean follow-up of 16.8 y, 1143 cohort subjects developed ESRD. Compared with those who drank coffee less than daily, the HR (95% CI) was 0.91 (0.79, 1.05) for those who drank 1 cup of coffee/d and 0.82 (0.71, 0.96) for those who drank ≥2 cups/d (P-trend = 0.012). When stratified by sex, this association was observed in men but not in women. Compared with those who drank less than daily, the HR (95% CI) for drinking ≥2 cups/d was 0.71 (0.57, 0.87) among men and 0.97 (0.78, 1.19) among women (P-interaction = 0.03). Conversely, intakes of tea, soda, or total caffeine were not associated with the risk of ESRD in multivariable models. Conclusion: The consumption of ≥2 cups of coffee/d may reduce the risk of ESRD in the general population, especially among men. This study was registered at www.clinicaltrials.gov as NCT03356340.

The relationship between body mass index (BMI) and end stage renal disease (ESRD) is confounded by co-morbidities associated with both conditions. Furthermore, the association at low range BMI is controversial. We studied this association in the Singapore Chinese Health Study, a population-based prospective cohort that recruited Singaporean Chinese men and women 45–74 years of age from 1993 to 1998. Self-reported weight, height, lifestyle factors, usual diet and medical history were collected via an interviewer-administered questionnaire. Incident ESRD cases were identified via record linkage with the nationwide ESRD registry. The computed Cox proportional hazard regression was adjusted for potential risk factors. After an average follow up of 15.5 years, 827 incident ESRD cases were identified. Compared with a normal BMI of 18.5 to under 23 kg/m2, the hazard ratios and (95% confidence intervals) of ESRD risk for BMIs under 18.5, 23 to under 27.5, and 27.5 kg/m2 or more were 0.54 (0.37–0.79), 1.40 (1.20–1.64) and 2.13 (1.74–2.59), respectively. This significantly trended, linear, dose-dependent association was only present among those with no history of diabetes, hypertension, coronary heart disease and stroke at baseline, but not significantly among those with any of these co-morbidities. Thus, BMI itself is a risk factor for ESRD in the general population and this association is present in those without preexisting diabetes, hypertension, coronary heart disease and stroke.