Association of a Province-Wide Intervention With Salt Intake and Hypertension in Shandong Province, China, 2011-2016 | Global Health | JAMA Internal Medicine | JAMA Network
[Skip to Navigation]
Sign In
Table 1.  Weighted Characteristics of Participants Aged 18 to 69 Years Between Preintervention and Postintervention Surveysa
Weighted Characteristics of Participants Aged 18 to 69 Years Between Preintervention and Postintervention Surveysa
Table 2.  Adjusted 24-h Urinary Sodium and Potassium Excretion and Sodium to Potassium Ratio Among Adults Aged 18 to 69 Years Between Preintervention and Postintervention Surveys in SMASH From 2011 to 2016
Adjusted 24-h Urinary Sodium and Potassium Excretion and Sodium to Potassium Ratio Among Adults Aged 18 to 69 Years Between Preintervention and Postintervention Surveys in SMASH From 2011 to 2016
Table 3.  Adjusted Systolic Blood Pressure and Diastolic Blood Pressure Among Adults Aged 18-69 Years Between Preintervention and Postintervention Surveys in SMASH from 2011 to 2016
Adjusted Systolic Blood Pressure and Diastolic Blood Pressure Among Adults Aged 18-69 Years Between Preintervention and Postintervention Surveys in SMASH from 2011 to 2016
Table 4.  Knowledge, Attitude, and Behavior Associated With Sodium Reduction Among Adults Aged 18 to 69 Years Between Preintervention and Postintervention Surveysa
Knowledge, Attitude, and Behavior Associated With Sodium Reduction Among Adults Aged 18 to 69 Years Between Preintervention and Postintervention Surveysa
1.
Zhou  M, Wang  H, Zeng  X,  et al.  Mortality, morbidity, and risk factors in China and its provinces, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.   Lancet. 2019;394(10204):1145-1158. doi:10.1016/S0140-6736(19)30427-1 PubMedGoogle ScholarCrossref
2.
Wang  Z, Chen  Z, Zhang  L,  et al; China Hypertension Survey Investigators.  Status of hypertension in China: results from the China Hypertension Survey, 2012-2015.   Circulation. 2018;137(22):2344-2356. doi:10.1161/CIRCULATIONAHA.117.032380 PubMedGoogle ScholarCrossref
3.
Murray  CJ, Lauer  JA, Hutubessy  RC,  et al.  Effectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk.   Lancet. 2003;361(9359):717-725. doi:10.1016/S0140-6736(03)12655-4 PubMedGoogle ScholarCrossref
4.
Aburto  NJ, Ziolkovska  A, Hooper  L, Elliott  P, Cappuccio  FP, Meerpohl  JJ.  Effect of lower sodium intake on health: systematic review and meta-analyses.   BMJ. 2013;346:f1326. doi:10.1136/bmj.f1326 PubMedGoogle ScholarCrossref
5.
Strazzullo  P, D’Elia  L, Kandala  NB, Cappuccio  FP.  Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies.   BMJ. 2009;339:b4567. doi:10.1136/bmj.b4567 PubMedGoogle ScholarCrossref
6.
He  FJ, Li  J, Macgregor  GA.  Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials.   BMJ. 2013;346:f1325. doi:10.1136/bmj.f1325 PubMedGoogle ScholarCrossref
7.
Du  S, Batis  C, Wang  H, Zhang  B, Zhang  J, Popkin  BM.  Understanding the patterns and trends of sodium intake, potassium intake, and sodium to potassium ratio and their effect on hypertension in China.   Am J Clin Nutr. 2014;99(2):334-343. doi:10.3945/ajcn.113.059121 PubMedGoogle ScholarCrossref
8.
The Chinese National Health and Family Planning Commission of the People’s Republic of China.  2015 report on Chinese nutrition and chronic disease. People's Medical Publishing House Co, Limited; 2015.
9.
Yang  Y, Zhang  M.  A brief introduction to dietary guidelines for Chinese residents.   Ying Yang Xue Bao. 2016;38(3):209-217.Google Scholar
10.
World Health Organization. Global Status Report on Noncommunicable Diseases 2010. World Health Organization; 2011. Accessed December 10, 2015. https://www.who.int/nmh/publications/ncd_report2010/en/
11.
He  FJ, MacGregor  GA.  A comprehensive review on salt and health and current experience of worldwide salt reduction programmes.   J Hum Hypertens. 2009;23(6):363-384. doi:10.1038/jhh.2008.144 PubMedGoogle ScholarCrossref
12.
Cobb  LK, Appel  LJ, Anderson  CAM.  Strategies to reduce dietary sodium intake.   Curr Treat Options Cardiovasc Med. 2012;14(4):425-434. doi:10.1007/s11936-012-0182-9 PubMedGoogle ScholarCrossref
13.
Trieu  K, Neal  B, Hawkes  C,  et al.  Salt reduction initiatives around the world—a systematic review of progress towards the global target.   PLoS One. 2015;10(7):e0130247. doi:10.1371/journal.pone.0130247 PubMedGoogle Scholar
14.
He  FJ, Marciniak  M, Visagie  E,  et al.  Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives.   Hypertension. 2009;54(3):482-488. doi:10.1161/HYPERTENSIONAHA.109.133223 PubMedGoogle ScholarCrossref
15.
Bi  Z, Liang  X, Xu  A,  et al.  Hypertension prevalence, awareness, treatment, and control and sodium intake in Shandong Province, China: baseline results from Shandong-Ministry of Health Action on Salt Reduction and Hypertension (SMASH), 2011.   Prev Chronic Dis. 2014;11:E88. doi:10.5888/pcd11.130423PubMedGoogle Scholar
16.
Shandong Provincial Bureau of Statistics. Statistical Communique on national economic and social development of Shandong Province in 2016. Published in Chinese. 2016. Accessed January 10, 2016. http://www.stats-sd.gov.cn/tjnj/nj2016/indexch.htm
17.
Wang  Q.  Review and prospective on salt archaeology in Shandong.   Huaxia Archaeology. 2012;4:59-69.Google Scholar
18.
Li  LM, Rao  KQ, Kong  LZ,  et al; Technical Working Group of China National Nutrition and Health Survey.  A description on the Chinese national nutrition and health survey in 2002.  Published in Chinese.  Zhonghua Liu Xing Bing Xue Za Zhi. 2005;26(7):478-484.PubMedGoogle Scholar
19.
Yan  L, Bi  Z, Tang  J,  et al.  Relationships between blood pressure and 24-hour urinary excretion of sodium and potassium by body mass index status in Chinese adults.   J Clin Hypertens (Greenwich). 2015;17(12):916-925. doi:10.1111/jch.12658 PubMedGoogle ScholarCrossref
20.
Zhang  J, Xu  AQ, Ma  JX,  et al.  Dietary sodium intake: knowledge, attitudes and practices in Shandong Province, China, 2011.   PLoS One. 2013;8(3):e58973. doi:10.1371/journal.pone.0058973 PubMedGoogle Scholar
21.
World Health Organization. Follow-up to the Political Declaration of the High-level Meeting of the General Assembly on the Prevention and Control of Non-communicable Diseases. 2013. Accessed May 27, 2013. https://apps.who.int/iris/bitstream/handle/10665/150161/A66_R10-en.pdf?sequence=1&isAllowed=y
22.
Lu  Z, Zhang  X, Li  J,  et al.  Dietary sodium intakes and resources among residents in Shandong province.  Published in Chinese.  Zhonghua Yu Fang Yi Xue Za Zhi. 2014;48(1):7-11.PubMedGoogle Scholar
23.
Sacks  FM, Svetkey  LP, Vollmer  WM,  et al; DASH-Sodium Collaborative Research Group.  Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet.   N Engl J Med. 2001;344(1):3-10. doi:10.1056/NEJM200101043440101 PubMedGoogle ScholarCrossref
24.
Mozaffarian  D, Fahimi  S, Singh  GM,  et al; Global Burden of Diseases Nutrition and Chronic Diseases Expert Group.  Global sodium consumption and death from cardiovascular causes.   N Engl J Med. 2014;371(7):624-634. doi:10.1056/NEJMoa1304127 PubMedGoogle ScholarCrossref
25.
Vollmer  WM, Sacks  FM, Ard  J,  et al; DASH-Sodium Trial Collaborative Research Group.  Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-sodium trial.   Ann Intern Med. 2001;135(12):1019-1028. doi:10.7326/0003-4819-135-12-200112180-00005 PubMedGoogle ScholarCrossref
26.
Li  Y, Wang  DD, Ley  SH,  et al.  Potential impact of time trend of life-style factors on cardiovascular disease burden in China.   J Am Coll Cardiol. 2016;68(8):818-833. doi:10.1016/j.jacc.2016.06.011 PubMedGoogle ScholarCrossref
27.
Attard  SM, Herring  AH, Zhang  B, Du  S, Popkin  BM, Gordon-Larsen  P.  Associations between age, cohort, and urbanization with SBP and DBP in China: a population-based study across 18 years.   J Hypertens. 2015;33(5):948-956. doi:10.1097/HJH.0000000000000522 PubMedGoogle ScholarCrossref
28.
Hardy  ST, Loehr  LR, Butler  KR,  et al.  Reducing the blood pressure–related burden of cardiovascular disease: impact of achievable improvements in blood pressure prevention and control.   J Am Heart Assoc. 2015;4(10):e002276. doi:10.1161/JAHA.115.002276 PubMedGoogle Scholar
29.
Zhang  J, Guo  X, Lu  Z,  et al.  Cardiovascular diseases deaths attributable to high sodium intake in Shandong Province, China.   J Am Heart Assoc. 2019;8(1):e010737. doi:10.1161/JAHA.118.010737 PubMedGoogle Scholar
30.
Yu  DM, Fu  P, Yu  WT,  et al.  Mean blood pressure among the adults in China 2010-2012: based on the results of mercury sphygmomanometer and converted electronic sphygmomanometer.  Article in Chinese.  Zhonghua Yu Fang Yi Xue Za Zhi. 2017;51(10):933-938.PubMedGoogle Scholar
31.
Hipgrave  DB, Chang  S, Li  X, Wu  Y.  Salt and sodium intake in China.   JAMA. 2016;315(7):703-705. doi:10.1001/jama.2015.15816 PubMedGoogle ScholarCrossref
32.
The State Council of the People’s Republic of China. State Council Issues the Medium-to-Long Term Plan for the Prevention and Treatment of Chronic Diseases to Clarify and Improve Medical Insurance Related Policies. Article in Chinese. 2017. Accessed February 14, 2017. http://www.gov.cn/zhengce/content/2017-02/14/content_5167886.htm
33.
Neiman  A, Leving  J, Ying  C. Two initiatives worth their salt: reducing sodium intake in Shandong, China and Philadelphia. 2015. Accessed September 28, 2015. https://www.cdc.gov/globalhealth/stories/reducing_sodium_2015.html
Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Not all submitted comments are published. Please see our commenting policy for details.

Limit 140 characters
Limit 3600 characters or approximately 600 words
    Original Investigation
    April 27, 2020

    Association of a Province-Wide Intervention With Salt Intake and Hypertension in Shandong Province, China, 2011-2016

    Author Affiliations
    • 1Shandong Center for Disease Control and Prevention, and Academy of Preventive Medicine, Shandong University, Jinan, China
    • 2Chinese Center for Disease Control and Prevention, Beijing, China
    • 3National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
    • 4National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, Beijing, China
    • 5Division for Heart Disease and Stroke Prevention Centers for Disease Control and Prevention, Atlanta, Georgia
    • 6Peking University Clinical Research Institute, Beijing, China
    • 7Division of Global Health Protection Centers for Disease Control and Prevention, Atlanta, Georgia
    • 8China National Salt Industry Company Limited, Beijing, China
    • 9Division of Preventive and Community Health, National Center for Cardiovascular Disease, The State Key Laboratory of Cardiovascular Disease, National Clinical Research Center of Cardiovascular Disease, Fuwai Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
    • 10Missouri Department of Mental Health, Jefferson City
    JAMA Intern Med. 2020;180(6):877-886. doi:10.1001/jamainternmed.2020.0904
    Key Points

    Question  Was a government-led, multisectoral, province-wide intervention associated with reduced sodium intake and blood pressure in Shandong Province, China, from 2011 to 2016?

    Findings  In this cross-sectional study of 15 350 preintervention participants and 16 490 postintervention participants, 24-hour urinary sodium excretion based on the subsamples of total preintervention and postintervention survey samples decreased 25% from before to after implementation of the intervention. Systolic and diastolic blood pressure decreased significantly.

    Meaning  The findings suggest that this population-based intervention was associated with lower urinary sodium excretion and blood pressure in a large population in China.

    Abstract

    Importance  High salt intake is associated with hypertension, which is a leading modifiable risk factor for cardiovascular disease.

    Objective  To assess the association of a government-led, multisectoral, and population-based intervention with reduced salt intake and blood pressure in Shandong Province, China.

    Design, Setting, and Participants  This cross-sectional study used data from the Shandong–Ministry of Health Action on Salt and Hypertension (SMASH) program, a 5-year intervention to reduce sodium consumption in Shandong Province, China. Two representative samples of adults (aged 18-69 years) were surveyed in 2011 (15 350 preintervention participants) and 2016 (16 490 postintervention participants) to examine changes in blood pressure, and knowledge, attitudes, and behaviors related to sodium intake. Urine samples were collected from random subsamples (2024 preintervention participants and 1675 postintervention participants) for measuring sodium and potassium excretion. Data were analyzed from January 20, 2017, to April 9, 2019.

    Interventions  Media campaigns, distribution of scaled salt spoons, promotion of low-sodium products in markets and restaurants, and activities to support household sodium reduction and school-based sodium reduction education.

    Main Outcomes and Measures  The primary outcome was change in urinary sodium excretion. Secondary outcomes were changes in potassium excretion, blood pressure, and knowledge, attitudes, and behaviors. Outcomes were adjusted for likely confounders. Means (95% CIs) and percentages were weighted.

    Results  Among 15 350 participants in 2011, 7683 (50.4%) were men and the mean age was 40.7 years (95% CI, 40.2-41.2 years); among 16 490 participants in 2016, 8077 (50.7%) were men and the mean age was 42.8 years (95% CI, 42.5-43.1 years). Among participants with 24-hour urine samples, 1060 (51.8%) were men and the mean age was 40.9 years (95% CI, 40.5-41.3 years) in 2011 and 836 (50.7%) were men and the mean age was 40.7 years (95% CI, 40.1-41.4 years) in 2016. The 24-hour urinary sodium excretion decreased 25% from 5338 mg per day (95% CI, 5065-5612 mg per day) in 2011 to 4013 mg per day (95% CI, 3837-4190 mg per day) in 2016 (P < .001), and potassium excretion increased 15% from 1607 mg per day (95% CI, 1511-1704 mg per day) to 1850 mg per day (95% CI, 1771-1929 mg per day) (P < .001). Adjusted mean systolic blood pressure among all participants decreased from 131.8 mm Hg (95% CI, 129.8-133.8 mm Hg) to 130.0 mm Hg (95% CI, 127.7-132.4 mm Hg) (P = .04), and diastolic blood pressure decreased from 83.9 mm Hg (95% CI, 82.6-85.1 mm Hg) to 80.8 mm Hg (95% CI, 79.4-82.1 mm Hg) (P < .001). Knowledge, attitudes, and behaviors associated with dietary sodium reduction and hypertension improved significantly.

    Conclusions and Relevance  The findings suggest that a government-led and population-based intervention in Shandong, China, was associated with significant decreases in dietary sodium intake and a modest reduction in blood pressure. The results of SMASH may have implications for sodium reduction and blood pressure control in other regions of China and worldwide.

    Introduction

    Cardiovascular disease (CVD) is the leading cause of death in China.1 Hypertension, which affects 23.2% of Chinese adults,2 is an important modifiable risk factor for CVD.3 Excess intake of sodium is associated with increased blood pressure (BP) and with increased risk of CVD.4-7 In China, the mean dietary salt intake was 10.5 g per day according to the most recent survey in 2012,8 approximately twice the amount recommended by the Chinese Dietary Guidelines9 (<6 g per day) or the World Health Organization (<5 g per day).10

    Population-based sodium reduction has been recommended by the World Health Organization as one of the best strategies for controlling CVD.10 Several resource-rich countries have successfully reduced population sodium intake by limiting the sodium content in manufactured food.11-13 However, alternative strategies are needed for low- and middle-income countries, such as China, where sodium intake is mainly from food prepared at home. Although randomized clinical trials have shown benefits of sodium reduction on BP,14 less is known about the potential association of population-based interventions with sodium reduction and changes in BP.

    The Shandong–Ministry of Health Action on Salt and Hypertension (SMASH) program15 was designed to engage multiple stakeholders in a government-led, collaborative, population-based, practical intervention. The Shandong Province of eastern China is the second most populous province in China, with more than 90 million residents.16 Shandong has been one of China’s largest salt-producing provinces since ancient times.17 In 2002, the mean dietary salt intake was 12.6 g per day in Shandong, which was above the national average.18 This study assessed whether use of this intervention was associated with reduced population sodium consumption and BP.

    Methods
    Settings

    This cross-sectional study used data from the SMASH program. To evaluate the intervention, 2 provincial representative cross-sectional surveys were performed in 2011 (preintervention survey) and 2016 (postintervention survey). SMASH was officially launched in March 2011, and implementation began after the baseline survey was conducted from June to July, 2011. Data were analyzed from January 20, 2017, to April 9, 2019. The preintervention surveys were approved by the ethics committees of the Shandong Center for Disease Control and Prevention. The postintervention surveys were approved by the National Center for Chronic and Noncommunicable Disease Control and Prevention and the Chinese Center for Disease Control and Prevention. All participants provided written informed consent and all analytic data were deidentified. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.

    Survey Design and Sampling

    We used stratified multistage (divided by region and socioeconomic development level) and probability proportional to size sampling methods to select 156 villages or communities in 8 urban districts and 12 rural counties. Random samples of 100 adults in 2011 and 110 adults in 2016 aged 18 to 69 years were drawn from each village or community, with a sum of 15 600 adults in 2011 and 17 160 adults in 2016. Among these participants, we randomly selected a subsample of 2112 individuals in 2011 and 2043 individuals in 2016 from a stratified random sample of 52 villages or communities for 24-hour urine sample collection for sodium and potassium assessment (eFigure 1 and eFigure 2 in the Supplement). The final samples in the 2011 survey consisted of 15 350 participants for the physical examinations and questionnaire interviews and a subsample of 2024 participants with complete 24-hour urinary data. The corresponding numbers were 16 490 participants for the examinations and interviews and 1675 participants for 24-hour urinary data in 2016. Sample size calculation and participation rates are presented in eMethods 1 in the Supplement.

    Preintervention and Postintervention Surveys

    All individuals were invited to participate in face-to-face interviews and physical examinations conducted in the central office of each community or village. Interviews focused on knowledge, attitudes, and behaviors (KABs) related to dietary sodium intake and hypertension and were administered by trained interviewers to ensure standardized methods (eTable 2 in the Supplement). Physical examinations included measurement of BP, height, weight, and waist circumference. Blood pressure was measured using a certified automated electronic sphygmomanometer (model HEM-7071; Omron Corporation). Details on participant recruitment, technician trainings, BP measurement, urine sample collection and analysis, and quality control measures are given in eMethods 2 in the Supplement and have been published previously.15,19

    Intervention

    The SMASH program used multisectoral intervention strategies and was implemented by 15 administrative departments across the province (eTable 1 in the Supplement). The program developed local food standards and regulations and promoted salt-reduction actions among caterers, supermarkets, and food-processing enterprises. Low-sodium food displays were established in 1461 supermarkets, promoting customer awareness of sodium labeling. To promote sodium reduction in home cooking, more than 13 million scaled salt spoons were widely distributed to households to facilitate awareness and measurement of salt added to food. The Shandong government launched intensive media campaigns to support the intervention. By the end of 2015, 1777 newspapers and 26 668 public broadcasts were disseminated to deliver relevant messaging to the population province-wide. Millions of posters, pamphlets, and signs were displayed in local schools, communities, restaurants, and cafeterias. More than 74 000 low-sodium diet advertising billboards were set up in communities, and 69 431 trainings were organized in local health agencies for the community members.

    Beyond public education, SMASH emphasized the proactive role of women and students in implementing the intervention. For women, who often serve as gatekeepers for diet and health in the household,20 a Family Salt Reduction Campaign was launched in collaboration with the Women Federation. Within the campaign, 1000 families were selected as role models for household sodium intake reduction. School interventions targeting students and their parents were implemented in 17 414 schools (87.5% of schools in Shandong Province).

    Another key partner, the Shandong Bureau of Salt Administration, printed low-sodium dietary tips on salt packages indicating that salt intake should not exceed 6 g per day. The bureau also promoted use of a low-sodium salt substitute that contains 30% potassium chloride.

    Outcomes

    The primary outcome was change in urinary sodium excretion from 2011 through 2016. Secondary outcomes were changes in potassium excretion, BP, and KABs. Results for BP and KABs were presented for all participants with available data, not restricted to the subset with urinary excretion data.

    Statistical Analysis

    Continuous variables were presented as weighted mean (95% CI), categorical variables were expressed as weighted percentages, and the differences between the 2 surveys were compared, accounting for survey design and sampling weights. Multivariable regression models compared differences in 24-hour urinary sodium levels, potassium levels, sodium to potassium ratio, BP, and KABs between the 2011 and 2016 surveys, adjusting for age, sex, occupation, educational level, body mass index, frequency of eating outside the home, hypertension status, and use of antihypertensive medications. To determine whether SMASH differentially affected subpopulations, we tested for interactions. All statistical tests were 2-sided, with P < .05 considered as statistically significant. Analyses were performed with SAS, version 9.4 (SAS Institute Inc).

    Results

    Among 15 350 participants in 2011, 7683 (50.4%) were men and the mean age was 40.7 years (95% CI, 40.2-41.2 years); among 16 490 participants in 2016, 8077 (50.7%) were men and the mean age was 42.8 years (95% CI, 42.5-43.1 years). Among participants with 24-hour urine samples, 1060 (51.8%) were men and the mean age was 40.9 years (95% CI, 40.5-41.3 years) in 2011 and 836 (50.7%) were men and the mean age was 40.7 years (95% CI, 40.1-41.4 years) in 2016 (Table 1). Other variables were not significantly different between 2011 and 2016. Mean body mass index was higher in 2016 than in 2011.

    Urinary Sodium Levels, Potassium Levels, and Sodium to Potassium Ratio

    The 24-hour urinary sodium excretion decreased significantly from 5338 mg per day (95% CI, 5065-5612 mg per day) in 2011 to 4013 mg per day (95% CI, 3837-4190 mg per day) in 2016, with an adjusted difference of 1325 mg per day (95% CI, 1016-1634 mg per day; P < .001). The mean potassium level increased significantly from 1607 mg per day (95% CI, 1511-1704 mg per day) to 1850 mg per day (95% CI, 1771-1929 mg per day) (P < .001), and the mean sodium to potassium ratio decreased significantly from 6.9 (95% CI, 6.3-7.5) to 4.3 (95% CI, 4.0-4.7) (P < .001) (Table 2). Changes were consistent across subpopulations, although there appeared to be a more pronounced reduction in sodium levels among participants eating at home and a more pronounced increase in potassium levels among older and underemployed or retired participants (Table 2).

    Changes in Systolic BP and Diastolic BP

    The adjusted mean systolic BP decreased by 1.8 mm Hg from 131.8 mm Hg (95% CI, 129.8-133.8 mm Hg) in 2011 to 130.0 mm Hg (95% CI, 127.7-132.4 mm Hg) in 2016 (P = .04). The adjusted mean diastolic BP decreased by 3.1 mm Hg from 83.9 mm Hg (95% CI, 82.6-85.1 mm Hg) to 80.8 mm Hg (95% CI, 79.4-82.1 mm Hg) (P < .001). Changes were consistent across subgroups but appeared to be more pronounced with increased age, prehypertension and hypertension, and lower educational attainment (Table 3).

    Changes in KABs

    There were significant increases in several KABs. The proportion of participants with knowledge of the salt intake recommendation by the Chinese Dietary Guidelines increased from 31.7% (95% CI, 23.3%-40.1%) to 57.6% (95% CI, 48.3%-66.9%) (P < .001). Significant improvements were also seen in self-reported scaled salt spoon use (14.6% [95% CI, 8.7%-20.6%] to 36.1% [95% CI, 28.4%-43.8%], P < .001), attention paid to processed food labeling (18.4% [95% CI, 12.5%-24.2%] to 32.1% [95% CI, 25.9%-38.2%], P < .001), and actions taken to reduce sodium in the diet (35.7% [95% CI, 28.6%-42.8%] to 61.1% [95% CI, 52.8%-69.5%], P < .001) (Table 4).

    Discussion

    The findings of the SMASH intervention showed that 24-hour urinary sodium excretion among adults decreased 24.8%, potassium excretion increased 15.1%, and the sodium to potassium ratio decreased 36.6% from 2011 to 2016. Both systolic BP (1.8 mm Hg) and diastolic BP (3.1 mm Hg) decreased significantly. Sodium-related behaviors, such as use of a scaled salt spoon, paying attention to sodium content of processed food, and making intentional efforts to reduce sodium intake in the diet, improved significantly. These improvements were seen across almost all sociodemographic subgroups.

    In 2013, the World Health Organization member states established a global target of 25% reduction in hypertension prevalence and 30% reduction in mean population sodium intake by 2025.21 Several countries have adopted national sodium reduction strategies.11-13 The findings from the SMASH program compared favorably with successful sodium reduction efforts in other countries. In a systematic review, 12 countries observed reductions in population sodium intake ranging from 5% to 36% during 5 to 29 years, including a 28.8% reduction in salt intake in China from 1991 through 2009 assessed by dietary intake.13 The 24.8% (1325 mg per day of sodium) reduction in 24-hour urinary sodium excretion observed in Shandong Province during 5 years from 2011 through 2016 was at the higher end of this range and was the most rapid reduction compared with other locations.

    There are several possible explanations for the large reduction in sodium excretion observed in SMASH. First, the main source of dietary sodium among Shandong residents is from home cooking.15,22 This dietary sodium is perhaps easier to target with public education compared with sodium in processed and restaurant foods. In 2011, condiments consumed at home contributed 80.8% of total sodium intake in Shandong, and only 10.1% sodium intake came from processed food15,22; this stands in sharp contrast to many high-income countries, where most sodium intake comes from processed and restaurant foods.13 Therefore, a key strategy of the SMASH intervention was to reduce the use of condiments containing sodium during cooking. A similar strategy was used successfully in Japan, which focused on key contributors of sodium in Japanese home cooking: soy sauce, salted vegetables, and miso soup.13 Second, there was the uniquely strong leadership of the National Health Commission of the People’s Republic of China and Shandong provincial government in the SMASH intervention, including the support and close cooperation of 15 government agencies at provincial, city, and county levels. Numerous culturally tailored communication strategies were used to promote sodium reduction. The observed improvements in knowledge and behaviors pertaining to sodium reduction during the study period might reflect these innovative communication strategies. Third, the nearly 8-fold increase in sales of low-sodium salt substitute containing 30% potassium chloride, which accounted for more than a quarter of sales of small packaged retail salt by the end of the study period, may have contributed to the reduction in sodium levels, the increase in potassium levels, and the decrease in sodium-potassium ratio. The contribution of low-sodium salt substitute merits further examination in a follow-up study.

    Reduction in population-level urinary sodium excretion was accompanied by a decrease in BP, especially diastolic BP in the population. Our findings were consistent with other studies that showed BP-lowering effects of sodium reduction and reduction of the sodium-potassium ratio.6,23,24 A meta-analysis of randomized clinical trials showed that a 75-mmol per day (1725 mg per day) reduction in urinary sodium excretion yielded a mean reduction in systolic BP of 4.18 mm Hg.6 However, the decrease of 1.8 mm Hg in systolic BP observed during the SMASH intervention period appeared to be smaller than would be expected from the reduction of 1325 mg per day in 24-hour urinary sodium excretion. This discrepancy could be attributable to various factors. First, the participants in SMASH were relatively young. The decrease in BP associated with salt reduction varies by age, and older individuals have greater reduction in BP.25 Second, there has been a continuing increase in BP from the early 1990s to 2012 in China,26 which might have mitigated the decrease in BP associated with salt reduction in SMASH. Nevertheless, SMASH suggests that a reduction in salt intake was associated with a counteraction in this increasing trend and may have been associated with a modest decrease in BP among individuals in Shandong Province. In addition, our results might be confounded by other factors such as the observed increase in body mass index.26 This might suggest that the systolic BP would have been higher in 2016 if there was no SMASH intervention. Further studies are needed to clarify the less than expected changes in systolic BP after the SMASH intervention. We also observed a significant reduction in diastolic BP. Although it was unexpected to observe a greater reduction in diastolic BP than systolic BP, this is consistent with a previous study27 that observed a stronger association of diastolic BP with environmental and risk factor changes among Chinese young adults in urban areas. This might partly explain the observed larger reduction in diastolic BP compared with systolic BP in SMASH.

    Although the observed reductions in BP were modest, even a slight population-wide reduction in BP might have a substantial association with CVD incidence.28 A study using SMASH baseline data estimated that 6700 deaths from CVD in Shandong could be prevented annually if urinary sodium excretion was reduced to 4000 mg per day. This target was nearly achieved in 2016 (4013 mg per day).29 In addition, the association of the SMASH intervention with improved sodium, BP, and KABs in the population might not be fully realized within 5 years given the presumable lag time between initiation and maximum adoption of the intervention, and effects might continue beyond the 5-year period.

    Province-wide changes in retail salt sales and BP in Shandong compare favorably to data collected from China overall. The sale of regular retail salt decreased 15.8% (329 000 to 277 000 tons) from 2011 to 2015 in Shandong compared with a 14.4% decrease (5 374 000 to 4 602 000 tons) in China. Meanwhile, the proportion of low-sodium retail salt sales increased from 2.7% to 20.6% (9000 to 72 000 tons) in Shandong compared with the increase from 0.7% to 7.8% (39 000 to 388 000 tons) in 2015 in China (Cui Jing, BME, China National Salt Industry Company Limited, Beijing, China, written communication, October 11, 2019). In addition, the results from 2 nationally representative surveys2,30 in China suggest that systolic BP increased (Chinese Nutrition and Health Surveillance survey [2010-2012]: 122.1 mm Hg [95% CI, 121.3-122.8 mm Hg] vs China Hypertension Survey [2012-2015]: 126.1 mm Hg [95% CI, 125.3-127.0 mm Hg]) and diastolic BP slightly decreased (2010-2012: 77.7 mm Hg [95% CI, 77.1-78.3 mm Hg] vs 2012-2015: 76.0 mm Hg [95% CI, 75.4-76.6 mm Hg]).2,30 These results suggest greater favorable changes in salt sales and BP in Shandong than in China overall during this period

    Strengths and Limitations

    Strengths of the SMASH study include the large provincial representative sample size, high participation rates, and the range of population subgroups assessed. Collection of 24-hour urine samples, considered the criterion standard for assessing sodium levels, was another strength. Also, careful efforts were made to standardize the assessment techniques for BP measurement and 24-hour urine sample collection, including the training of technicians and use of quality control measures.

    The primary limitation of this study is that SMASH was a province-wide intervention, and there was no control group. Therefore, it was not possible to attribute the observed changes in urinary sodium excretion and BP entirely to the intervention. Our results should be interpreted with caution. However, data from salt sales including the sales of salt substitute, urinary measurements of sodium and potassium levels, BP measurements, and KAB questions were mutually consistent and suggest that the observed reductions in salt intake and BP were not by chance.

    In addition to the lack of a control group, this study had other limitations. The characteristics of the participants in the 2 surveys had statistically significant differences, including age structure, body mass index, and socioeconomic factors. These differences might reflect demographic changes in Shandong during this time. For example, according to Shandong census data in 2009 and 2015, the proportion of the resident population younger than 40 years decreased from 47.6% to 41.8%. Increases in age and body mass index between 2011 and 2016 might have been expected to be associated with increased BP and blunted the intended outcomes of SMASH; other differences because of demographic changes or sampling errors might have had blunting, reinforcing, or no net outcomes. Sampling weights were applied to survey data to account for demographic differences.

    The KABs were self-reported and might be subject to recall or other bias, although results were consistent with 24-hour urinary measurements. The study period was 5 years, and the long-term association of sodium reduction with BP changes might not be fully captured within this time frame. Other societal changes unrelated to SMASH, such as changes in the primary public health service, food supply, and preservation practices,31 might have also contributed to the changes in sodium and BP during the study period.

    In 2017, the China State Council released the China National Medium and Long-Term Plan on Chronic Diseases Prevention and Control (2017–2025),32 targeting a 15% reduction in population sodium intake. The SMASH program in Shandong Province has been expanded to other provinces in support of the achievement of 2025 national targets. Lessons learned from the SMASH program might also help refine strategies and interventions for sodium level reduction in other settings as has already been shown in collaboration with the Philadelphia Healthy Chinese Take-out Restaurant Initiative.33

    Conclusions

    The SMASH program showed that a comprehensive, population-based intervention with strong government support was associated with a substantial decrease in urinary sodium excretion and a modest reduction in BP. The findings should be verified in other populations and periods. In particular, the value of such interventions compared with many potentially good interventions that could be considered at the population level merits more investigation.

    Back to top
    Article Information

    Accepted for Publication: February 6, 2020.

    Corresponding Authors: Xiaofeng Liang, MD, MPH (liangxf@chinacdc.cn), Chinese Center for Disease Control and Prevention, No. 155 Changbai Rd, Changping District, Beijing 102206, China; Zhenqiang Bi, PhD, Shandong Center for Disease Control and Prevention, and Academy of Preventive Medicine, Shandong University, Jinan, China (bzq63@163.com).

    Published Online: April 27, 2020. doi:10.1001/jamainternmed.2020.0904

    Author Contributions: Drs A. Xu and Ma contributed equally. Drs Ma and Guo had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

    Concept and design: A. Xu, Ma, Guo, J. Wu, J. Zhang, Bai, Lu, Ding, Y. Wu, X. Cai, C. Xu, Yang, Y. Cai, Y. Wang, Bi, Liang, L. Wang.

    Acquisition, analysis, or interpretation of data: A. Xu, Ma, Guo, J. Wu, J. Xu, Lu, Z. Xu, X. Zhang, Hong, Du, Y. Wu, Yan, Tang, X. Cai, Dong, C. Xu, Ren, Chen, Gao, B. Zhang, Yang, Moolenaar, Y. Cai, Jackson, Xie, Yu, Cui, Z. Wang, Zhao, Ju, Shen, Yun, Bi.

    Drafting of the manuscript: A. Xu, Ma, Guo, J. Wu, Bai, Z. Xu, Tang, X. Cai, Dong, C. Xu, Ren, Gao, B. Zhang, Yang, Moolenaar, Y. Cai, Y. Wang, Bi, L. Wang.

    Critical revision of the manuscript for important intellectual content: A. Xu, Ma, Guo, J. Wu, J. Zhang, Bai, J. Xu, Lu, Z. Xu, X. Zhang, Ding, Hong, Du, Y. Wu, Yan, X. Cai, Chen, Yang, Moolenaar, Jackson, Xie, Yu, Cui, Z. Wang, Zhao, Ju, Shen, Yun, Bi, Liang.

    Statistical analysis: A. Xu, Ma, Guo, J. Wu, J. Zhang, Lu, Z. Xu, X. Zhang, Du, Dong, C. Xu, Ren, Chen, Gao, B. Zhang, Yang, Xie, Yu, Z. Wang, Ju, Shen, Yun.

    Obtained funding: A. Xu, Guo, X. Cai, Y. Wang, Bi.

    Administrative, technical, or material support: J. Wu, Bai, J. Xu, Lu, X. Zhang, Hong, Yan, Tang, X. Cai, C. Xu, Ren, Yang, Moolenaar, Y. Cai, Cui, Zhao, Bi, Liang, L. Wang.

    Supervision: X. Zhang, Ding, Y. Wu, Yang, Moolenaar, Y. Wang, Bi.

    Conflict of Interest Disclosures: Dr Y Wu reported receiving grants from the China Ministry of Science and Technology and the Chongqing Jiankangyuan Company outside the submitted work. No other disclosures were reported.

    Funding/Support: This study was supported by grant 1311400010601 to the Shandong Provincial Salt and Hypertension Prevention and Control Intervention Project from the Chinese Center for Disease Control and Prevention, Provincial Technical Development Plan Grant 2012GSF11828, and Taishan Scholars Program of Shandong Government, China.

    Role of the Funder/Sponsor: The staff of the Chinese Center for Disease Control and Prevention and the US Centers for Disease Control and Prevention were involved in study design, data interpretation, and manuscript drafting. The staff of the Shandong Center for Disease Control and Prevention were involved in intervention implementation and data collection. The staff of the Peking University were involved in data analysis and interpretation.

    Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the US Centers for Disease Control and Prevention.

    Additional Contributions: We thank all the contributors from the national, provincial, and county levels in China and the participants of the intervention and evaluation survey. We acknowledge the technical support from the US Centers for Disease Control and Prevention (Atlanta, GA), especially Thomas R. Frieden, MD (currently with Resolve to Save Lives, Vital Strategies, New York, NY), who contributed to the study initiation, design, and comments about the manuscript. Prof Shenghan Lai, MD (Departments of Pathology, Psychiatry, Radiology, Medicine, and Epidemiology, Johns Hopkins University School of Medicine, Baltimore, MD), provided helpful comments and contributions to the draft manuscript. These individuals were not financially compensated.

    References
    1.
    Zhou  M, Wang  H, Zeng  X,  et al.  Mortality, morbidity, and risk factors in China and its provinces, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017.   Lancet. 2019;394(10204):1145-1158. doi:10.1016/S0140-6736(19)30427-1 PubMedGoogle ScholarCrossref
    2.
    Wang  Z, Chen  Z, Zhang  L,  et al; China Hypertension Survey Investigators.  Status of hypertension in China: results from the China Hypertension Survey, 2012-2015.   Circulation. 2018;137(22):2344-2356. doi:10.1161/CIRCULATIONAHA.117.032380 PubMedGoogle ScholarCrossref
    3.
    Murray  CJ, Lauer  JA, Hutubessy  RC,  et al.  Effectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk.   Lancet. 2003;361(9359):717-725. doi:10.1016/S0140-6736(03)12655-4 PubMedGoogle ScholarCrossref
    4.
    Aburto  NJ, Ziolkovska  A, Hooper  L, Elliott  P, Cappuccio  FP, Meerpohl  JJ.  Effect of lower sodium intake on health: systematic review and meta-analyses.   BMJ. 2013;346:f1326. doi:10.1136/bmj.f1326 PubMedGoogle ScholarCrossref
    5.
    Strazzullo  P, D’Elia  L, Kandala  NB, Cappuccio  FP.  Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies.   BMJ. 2009;339:b4567. doi:10.1136/bmj.b4567 PubMedGoogle ScholarCrossref
    6.
    He  FJ, Li  J, Macgregor  GA.  Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials.   BMJ. 2013;346:f1325. doi:10.1136/bmj.f1325 PubMedGoogle ScholarCrossref
    7.
    Du  S, Batis  C, Wang  H, Zhang  B, Zhang  J, Popkin  BM.  Understanding the patterns and trends of sodium intake, potassium intake, and sodium to potassium ratio and their effect on hypertension in China.   Am J Clin Nutr. 2014;99(2):334-343. doi:10.3945/ajcn.113.059121 PubMedGoogle ScholarCrossref
    8.
    The Chinese National Health and Family Planning Commission of the People’s Republic of China.  2015 report on Chinese nutrition and chronic disease. People's Medical Publishing House Co, Limited; 2015.
    9.
    Yang  Y, Zhang  M.  A brief introduction to dietary guidelines for Chinese residents.   Ying Yang Xue Bao. 2016;38(3):209-217.Google Scholar
    10.
    World Health Organization. Global Status Report on Noncommunicable Diseases 2010. World Health Organization; 2011. Accessed December 10, 2015. https://www.who.int/nmh/publications/ncd_report2010/en/
    11.
    He  FJ, MacGregor  GA.  A comprehensive review on salt and health and current experience of worldwide salt reduction programmes.   J Hum Hypertens. 2009;23(6):363-384. doi:10.1038/jhh.2008.144 PubMedGoogle ScholarCrossref
    12.
    Cobb  LK, Appel  LJ, Anderson  CAM.  Strategies to reduce dietary sodium intake.   Curr Treat Options Cardiovasc Med. 2012;14(4):425-434. doi:10.1007/s11936-012-0182-9 PubMedGoogle ScholarCrossref
    13.
    Trieu  K, Neal  B, Hawkes  C,  et al.  Salt reduction initiatives around the world—a systematic review of progress towards the global target.   PLoS One. 2015;10(7):e0130247. doi:10.1371/journal.pone.0130247 PubMedGoogle Scholar
    14.
    He  FJ, Marciniak  M, Visagie  E,  et al.  Effect of modest salt reduction on blood pressure, urinary albumin, and pulse wave velocity in white, black, and Asian mild hypertensives.   Hypertension. 2009;54(3):482-488. doi:10.1161/HYPERTENSIONAHA.109.133223 PubMedGoogle ScholarCrossref
    15.
    Bi  Z, Liang  X, Xu  A,  et al.  Hypertension prevalence, awareness, treatment, and control and sodium intake in Shandong Province, China: baseline results from Shandong-Ministry of Health Action on Salt Reduction and Hypertension (SMASH), 2011.   Prev Chronic Dis. 2014;11:E88. doi:10.5888/pcd11.130423PubMedGoogle Scholar
    16.
    Shandong Provincial Bureau of Statistics. Statistical Communique on national economic and social development of Shandong Province in 2016. Published in Chinese. 2016. Accessed January 10, 2016. http://www.stats-sd.gov.cn/tjnj/nj2016/indexch.htm
    17.
    Wang  Q.  Review and prospective on salt archaeology in Shandong.   Huaxia Archaeology. 2012;4:59-69.Google Scholar
    18.
    Li  LM, Rao  KQ, Kong  LZ,  et al; Technical Working Group of China National Nutrition and Health Survey.  A description on the Chinese national nutrition and health survey in 2002.  Published in Chinese.  Zhonghua Liu Xing Bing Xue Za Zhi. 2005;26(7):478-484.PubMedGoogle Scholar
    19.
    Yan  L, Bi  Z, Tang  J,  et al.  Relationships between blood pressure and 24-hour urinary excretion of sodium and potassium by body mass index status in Chinese adults.   J Clin Hypertens (Greenwich). 2015;17(12):916-925. doi:10.1111/jch.12658 PubMedGoogle ScholarCrossref
    20.
    Zhang  J, Xu  AQ, Ma  JX,  et al.  Dietary sodium intake: knowledge, attitudes and practices in Shandong Province, China, 2011.   PLoS One. 2013;8(3):e58973. doi:10.1371/journal.pone.0058973 PubMedGoogle Scholar
    21.
    World Health Organization. Follow-up to the Political Declaration of the High-level Meeting of the General Assembly on the Prevention and Control of Non-communicable Diseases. 2013. Accessed May 27, 2013. https://apps.who.int/iris/bitstream/handle/10665/150161/A66_R10-en.pdf?sequence=1&isAllowed=y
    22.
    Lu  Z, Zhang  X, Li  J,  et al.  Dietary sodium intakes and resources among residents in Shandong province.  Published in Chinese.  Zhonghua Yu Fang Yi Xue Za Zhi. 2014;48(1):7-11.PubMedGoogle Scholar
    23.
    Sacks  FM, Svetkey  LP, Vollmer  WM,  et al; DASH-Sodium Collaborative Research Group.  Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet.   N Engl J Med. 2001;344(1):3-10. doi:10.1056/NEJM200101043440101 PubMedGoogle ScholarCrossref
    24.
    Mozaffarian  D, Fahimi  S, Singh  GM,  et al; Global Burden of Diseases Nutrition and Chronic Diseases Expert Group.  Global sodium consumption and death from cardiovascular causes.   N Engl J Med. 2014;371(7):624-634. doi:10.1056/NEJMoa1304127 PubMedGoogle ScholarCrossref
    25.
    Vollmer  WM, Sacks  FM, Ard  J,  et al; DASH-Sodium Trial Collaborative Research Group.  Effects of diet and sodium intake on blood pressure: subgroup analysis of the DASH-sodium trial.   Ann Intern Med. 2001;135(12):1019-1028. doi:10.7326/0003-4819-135-12-200112180-00005 PubMedGoogle ScholarCrossref
    26.
    Li  Y, Wang  DD, Ley  SH,  et al.  Potential impact of time trend of life-style factors on cardiovascular disease burden in China.   J Am Coll Cardiol. 2016;68(8):818-833. doi:10.1016/j.jacc.2016.06.011 PubMedGoogle ScholarCrossref
    27.
    Attard  SM, Herring  AH, Zhang  B, Du  S, Popkin  BM, Gordon-Larsen  P.  Associations between age, cohort, and urbanization with SBP and DBP in China: a population-based study across 18 years.   J Hypertens. 2015;33(5):948-956. doi:10.1097/HJH.0000000000000522 PubMedGoogle ScholarCrossref
    28.
    Hardy  ST, Loehr  LR, Butler  KR,  et al.  Reducing the blood pressure–related burden of cardiovascular disease: impact of achievable improvements in blood pressure prevention and control.   J Am Heart Assoc. 2015;4(10):e002276. doi:10.1161/JAHA.115.002276 PubMedGoogle Scholar
    29.
    Zhang  J, Guo  X, Lu  Z,  et al.  Cardiovascular diseases deaths attributable to high sodium intake in Shandong Province, China.   J Am Heart Assoc. 2019;8(1):e010737. doi:10.1161/JAHA.118.010737 PubMedGoogle Scholar
    30.
    Yu  DM, Fu  P, Yu  WT,  et al.  Mean blood pressure among the adults in China 2010-2012: based on the results of mercury sphygmomanometer and converted electronic sphygmomanometer.  Article in Chinese.  Zhonghua Yu Fang Yi Xue Za Zhi. 2017;51(10):933-938.PubMedGoogle Scholar
    31.
    Hipgrave  DB, Chang  S, Li  X, Wu  Y.  Salt and sodium intake in China.   JAMA. 2016;315(7):703-705. doi:10.1001/jama.2015.15816 PubMedGoogle ScholarCrossref
    32.
    The State Council of the People’s Republic of China. State Council Issues the Medium-to-Long Term Plan for the Prevention and Treatment of Chronic Diseases to Clarify and Improve Medical Insurance Related Policies. Article in Chinese. 2017. Accessed February 14, 2017. http://www.gov.cn/zhengce/content/2017-02/14/content_5167886.htm
    33.
    Neiman  A, Leving  J, Ying  C. Two initiatives worth their salt: reducing sodium intake in Shandong, China and Philadelphia. 2015. Accessed September 28, 2015. https://www.cdc.gov/globalhealth/stories/reducing_sodium_2015.html
    ×