Influence of salty food preference on daily salt intake in primary care

Abstract

Kazuhiro Takamura,1 Masanobu Okayama,2 Taro Takeshima,2 Shinji Fujiwara,3 Masanori Harada,4 Junichi Murakami,5 Masahiko Eto,6 Eiji Kajii21Department of Community Medicine, Obstetrics and Gynecology, Miyazaki Prefectural Miyazaki Hospital, Miyazaki, Japan; 2Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan; 3Mima City National Health Insurance Koyadaira Clinic, Mima, Tokushima, Japan; 4Department of Support of Rural Health Care, Yamaguchi Grand Medical Center, Hofu, Yamaguchi, Japan; 5Division of Chest Surgery, Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan; 6Department of Internal Medicine, Wakuya Medical and Welfare Center, Wakuya, Miyagi, JapanPurpose: A salt preference questionnaire may be a convenient and cost-effective method for predicting salt intake; however, the influence of salt preference on daily salt intake is unclear. This study aimed at revealing the effectiveness of the salt preference question in determining the daily salt intake in primary care outpatients.Patients and methods: This cross-sectional study included 1,075 outpatients (men, n=436, 40.6%) at six primary care institutions in Japan. Primary outcomes included a salty food preference assessed by using one question and a daily salt intake, assessed using early morning second urine samples. Multivariate analyses determined the relationships between the salt intake and the two salt preference levels.Results: The mean age was 67.6±14.6 years, and 594 (55.3%) preferred salty foods. The daily salt intake was 12.3±4.0 g per day and 11.4±3.7 g per day in the salt preference and nonsalt preference groups, respectively (P<0.001). A salt intake <10 g per day was consumed by 169 (28.5%) and 181 (37.6%) patients (P=0.001), respectively, and <6 g salt per day was consumed by 28 (4.7%) and 26 (5.4%) patients (P=0.606), respectively. The patients who preferred salty foods consumed a significantly larger amount of salt per day than those who did not prefer salty foods (β coefficient, 0.621; 95% confidence interval [CI], 0.146–1.095). There was no difference in the number of patients who consumed <10 g salt per day (adjusted odds ratio [ad-OR], 1.29; 95% CI, 0.99–1.69) or <6 g salt per day (ad-OR, 1.39; 0.90–1.69) between the groups.Conclusion: Preference for salty foods was positively associated with daily salt intake. However, daily salt intake was not always appropriate, even in the patients who did not prefer salty foods. Behavioral interventions for salt restriction after an assessment of daily salt intake are necessary for primary care patients, regardless of their preference for salty foods.Keywords: salt preference, daily salt intake, outpatients, primary care, salt restriction, spot urine method