Age- and sex-specific reference intervals for renin and aldosterone in healthy individuals in Yunnan Province, China

Measurements of renin and aldosterone are important for the diagnosis and treatment of different renin sub-types of hypertension as well as endocrine hypertension, particularly primary aldosteronism (PA). However, numerous factors can influence the measurements of renin and aldosterone, including geographical location, ethnicity, body posture, dietary habits, sex, and age, instrumentation, methodology. This study aimed to establish age- and sex-specific reference intervals for renin and aldosterone in Yunnan Province, China. This study was a cross-sectional survey conducted in Yunnan Province, China, using multi-stage stratified random sampling method from four districts/counties and urban and rural settings. Age, gender, medical history, medication history and family history of the individuals were first collected, then height, weight, blood pressure and heart rate were measured and blood specimens were collected to test biochemical parameters, plasma renin concentration (PRC) and plasma aldosterone concentration (PAC). During the selection process, we first excluded individuals with obvious clinical symptoms and diagnosed diseases, and selected 9129 ostensibly healthy as the initial sample. Next, we excluded participants who were in pregnancy, lactating, taking contraceptive, hypertension, hypokalemia, renal insufficiency, obesity, and finally successfully included 5200 individuals. A rigorous statistical analysis was conducted to investigate differences in renin and aldosterone levels by sex and age, facilitating the redefinition of groups, and subsequently, reference intervals for renin and aldosterone were established within the redefined groups. Renin and aldosterone levels differed significantly across sex and age groups. Specifically, PRC was significantly lower in women than men, while PAC was significantly higher in men than women. PRC decreased with age, while PAC levels were lowest in the 18-24 age group and peaked in the 25-64 age group. Our findings underscore the crucial role of sex and age when precisely evaluating renin and aldosterone levels. This study established, for the first time, age- and sex-specific reference intervals for renin and aldosterone in healthy individuals in Yunnan Province, China. These findings may provide some guidance for the diagnosis and treatment of different renin sub-types of hypertension, as well as some help in providing new ideas for further research on PA.