Increased body mass index is a risk factor for end-stage renal disease in the Chinese Singapore population

Abstract

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 pre-existing diabetes, hypertension, coronary heart disease, and stroke.

Keywords: Singapore Chinese Health Study; body mass index; end-stage renal disease; epidemiology.

Fig 1a

Restricted cubic spline demonstrating the linear dose-dependent increase in hazard ratios (95% confidence intervals) for risk of ESRD according to BMI in a sub-cohort of subjects without any history of known co-morbid risk factors (ie. Diabetes, hypertension, chronic heart disease or stroke) in a model that adjusted for age, gender, dialect, educational level and year of interview, physical activity, smoking status, alcohol use, total energy intake, protein intake and red meat intake.

Figure 1b

Restricted cubic spline demonstrating the linear dose-dependent increase in hazard ratios (95% confidence intervals) for risk of ESRD according to BMI in a sub-cohort of subjects with history of at least one of the co-morbid risk factors (diabetes, hypertension, stroke or chronic heart disease) in a model that adjusted for age, gender, dialect, educational level and year of interview, physical activity, smoking status, alcohol use, total energy intake, protein intake and red meat intake.