Prospective Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hypertens. Nov 23, 2015; 5(4): 129-136
Published online Nov 23, 2015. doi: 10.5494/wjh.v5.i4.129
Estimated net endogenous acid production and risk of prevalent and incident hypertension in community-dwelling older people
Ruth Chan, Jason Leung, Jean Woo
Ruth Chan, Jean Woo, Department of Medicine and Therapeutics, the Chinese University of Hong Kong, Shatin, Hong Kong, China
Jason Leung, Jockey Club Centre for Osteoporosis Care and Control, the Chinese University of Hong Kong, Shatin, Hong Kong, China
Author contributions: Chan R conceptualized the study, performed data analysis and drafted the manuscript; Leung J assisted in data analysis and results interpretation and provided comments on the manuscript; Woo J provided administrative support for the study and commented on the manuscript; all authors read and approved the final manuscript.
Supported by Grants from the Research Grants Council of Hong Kong, CUHK 4101/02M; the Hong Kong Jockey Club Charities Trust; the SH Ho Centre for Gerontology and Geriatric; and the Centre for Nutritional Studies, The Chinese University of Hong Kong.
Institutional review board statement: This study was conducted in accordance with the Declaration of Helsinki. This study was approved by the Clinical Research Ethics Committee of the Chinese University of Hong Kong.
Clinical trial registration statement: Not applicable for this study.
Informed consent statement: Written informed consent was obtained from all subjects.
Conflict-of-interest statement: The authors of this manuscript have no conflicts of interest to disclose.
Data sharing statement: There is no additional data available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Ruth Chan, Research Assistant Professor, Department of Medicine and Therapeutics, the Chinese University of Hong Kong, Rm 124021, 10/F Lui Che Woo Clinical Sciences Building, Prince of Wales Hospital, Shatin, Hong Kong, China. ruthchansm@cuhk.edu.hk
Telephone: +852-26322190 Fax: +852-26379215
Received: June 8, 2015
Peer-review started: June 10, 2015
First decision: July 10, 2015
Revised: September 30, 2015
Accepted: October 23, 2015
Article in press: October 27, 2015
Published online: November 23, 2015
Abstract

AIM: To investigate the associations of dietary acid-base load with prevalent and incident hypertension in community-living Chinese older adults in Hong Kong.

METHODS: Participants aged ≥ 65 years participating in a cohort study examining the risk factors for osteoporosis completed a validated food frequency questionnaire (FFQ) at baseline between 2001 and 2003. Estimated net endogenous acid production (NEAP) was calculated using Frassetto’s method based on the diet’s protein to potassium ratio derived from the FFQ. Prevalent and 4-year incident hypertension was defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg and/or self-reported use of anti-hypertensive medications. Multivariable logistic regression was used for cross-sectional analysis (n = 3956) to assess the association between estimated NEAP and prevalent hypertension, and for longitudinal analysis (n = 795) on its association with 4-year incident hypertension, with adjustment for various potential socio-demographic and lifestyle factors.

RESULTS: Median estimated NEAP of the participants was 47.7 (interquartile range: 36.2, 60.9) g/mEq. Participants in the highest quartile of energy-adjusted estimated NEAP was associated with increased likelihood of prevalent hypertension than those in the lowest quartile of energy-adjusted estimated NEAP [multivariable OR = 1.66 (95%CI: 1.22 to 2.26, Ptrend = 0.002)]. No significant association was observed between energy-adjusted estimated NEAP and risk of incident hypertension.

CONCLUSION: A high dietary acid load was independently associated with an increased likelihood of prevalent hypertension in ambulant older Chinese people in Hong Kong. The longitudinal analyses failed to show any causal relationship between dietary acid load and hypertension in this population.

Keywords: Acid-base balance, Cohort, Hypertension, Nutrition, Chinese

Core tip: This prospective study investigated the associations between baseline dietary acid-base load and prevalent and 4-year incident hypertension in community-dwelling Chinese older adults in Hong Kong. Baseline dietary data were collected using a validated food frequency questionnaire (FFQ). Estimated dietary net endogenous acid production (NEAP) was calculated based on the diet’s protein to potassium ratio from the FFQ. Higher quartile of energy-adjusted estimated NEAP was associated with increased likelihood of prevalent hypertension [multivariable OR = 1.66 (95%CI: 1.22 to 2.26, Ptrend = 0.002)]. No significant association was observed between energy-adjusted estimated NEAP and risk of incident hypertension.