Effects of environmental and genetic risk factors for salt sensitivity on blood pressure in northern China: the systemic epidemiology of salt sensitivity (EpiSS) cohort study

PURPOSE: The systemic epidemiology of salt sensitivity (EpiSS) study aims to combine molecular biology, epidemiology and bioinformatics methods to discover the potential causes of salt sensitivity of blood pressure (SSBP) using single-nucleotide polymorphisms in the genome and non-coding RNAs in the transcriptome to uncover both the genetic and environmental factors of SSBP. PARTICIPANTS: Between July 2014 and July 2016, we enrolled adults from 11 study centres in Beijing and Liaoning Province; participants were of the Han population and were 35–70 years of age. We collected blood samples, spot urine samples and 24-hour urine samples, in addition to baseline data on demographics, health-related lifestyle factors, chronic diseases, family history of illness and anthropometric information through face-to-face interviews using a standardised questionnaire. EpiSS uses the modified Sullivan’s acute oral saline load and diuresis shrinkage test (MSAOSL-DST) to evaluate the effects of salt on blood pressure. FINDINGS TO DATE: In total, 2163 participants were included in the EpiSS, of which 2144 participants completed the questionnaire, 2120 (98.0%) completed the MSAOSL-DST and 2083 (96.3%) provided a 24-hour urine sample. A total of 2057 participants (1501 women and 556 men) completed all the steps of the investigation and were included in the analysis. Among them, 583 (28.3%) subjects were classified as having salt sensitivity of blood pressure, and 1061 (51.6%) had hypertension. FUTURE PLANS: The next step of our study is to evaluate the incidence of cardiovascular disease in the participants. Biennial follow-up, including face-to-face questionnaire surveys, laboratory measurements of blood, urinary creatinine, glomerular filtration rate and anthropometric measurements, will occur two additional times. DNA and RNA will be collected for subsequent genetic biomarker studies. We plan on screening the salt-sensitive-related gene loci and non-coding RNAs based on relative environmental risk factors. TRIAL REGISTRATION NUMBER: ChiCTR-EOC-16009980; Pre-results.