Effects of Microalbuminuria on the Relationships between Blood Pressure and Salt Intake in Japanese Population

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13670393
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Public health/Health science
• Research Institution: KANAZAWA MEDICAL UNIVERSITY
• Principal Investigator: NISHIJO Muneko Kanazawa Medical University, Lecturer, 医学部, 講師 (40198461)
• Co-Investigator(Kenkyū-buntansha): UESHIMA Hirotugu Shiga Medical University, Professor, 医学部, 教授 (70144483) ; MIURA Katsuyuki Kanazawa Medical University, Associate Professor, 医学部, 助教授 (90257452) ; NAKAGAWA Hideaki Kanazawa Medical University, Professor, 医学部, 教授 (00097437) ; SAITO Shigeyuki Sapporo Medical University, Lecturer, 医学部, 講師 (60253994) ; SAKATA Kiyomi Wakayama Prefecture University, Associate Professor, 医学部, 助教授 (50225794)
• Project Period (FY): 2001 – 2002
• Keywords: Microalbuminuria / Hypertension / 24-hour urine collection / Salt intake / Nutrition / Urinary C peptide / Insulin resistance

Research Abstract

Data collected by the International Population Study on Macronutrients and Blood Pressure Study (INTERMAP) in 1997-99 were used to assess relations of lifestyle-related cardiovascular risk factors and dietary factors to urinary albumin concentration in two-timed 24-hour urine specimens. The study population included 1,071 non-diabetic Japanese men and women aged 40-59 without macroalbuminuria (>=300mg/24hour) living in 4 areas. Microalbuminuria (MA) was defined as urinary albumin concentration was 30-300mg/24hour in both of 2 timed urinary collections, and MA possible (MAP) as either of them.
Prevalence of MA was 5.0% in men and 1.7% in women, and its gender difference was observed. Similarly, prevalence of MAP was 7.4% in men and 4.5% in women, but the gender difference was found only in 50's. The rate of hypertension (systolic blood pressure >=140mmHg, diastolic blood pressure >=90mmHg, or under unti-hypertensive medication) of the subjects with MA or MAP was higher than that of the subjects without MA or MAP. After adjusting age and BMI by logistic model, the significant relationship between hypertension and MA/MAP was found in both sexes. However, no difference of salt intake and urinary Na and Na/K ratio which are biological indices of salt intake, and urinary C-peptide which related to Insulin excretion between the subjects with and without MA/MAP in men. In women, there was no increase of urinary C-peptide, but urinary Na excretion of the subjects with MA/MAP was higher than that without MA/AMP.
In normotensive men, the level of diastolic blood pressure of the subjects with MA/MAP was higher than that of the men without MA/MAP, but no difference of relationship between salt intake and blood pressure was observed between these 2 groups. However, positive relationship between salt intake and diastolic blood pressure in the women with MAP in women.