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According to the 2018 Report on Cardiovascular Disease in China, hypertension and cardiovascular diseases (CVDs) were estimated to account for more than 40.0% of all deaths in China and were the leading cause of all death (1). Excessive salt intake is an important risk factor for CVDs, and China has one of the highest salt intakes in the world. According to the “National Nutrition and Health Survey of Chinese Residents,” the average salt intake among Chinese residents was 12 grams/day (g/d) in 2002 and 10.5 g/d in 2012 (2), which were both much higher than the maximum daily salt intake (6 g/d) recommended by “Dietary Guidelines for Chinese Residents”. However, most Chinese residents were still unclear about the recommended maximum daily salt intake. The awareness of maximum daily salt intake, the salt reduction behavior, and associated factors of Chinese residents aged 18 years old and above were analyzed by using data from the China Chronic Diseases and Nutrition Surveillance (CCDNS) system in 2015 for providing the evidence and basis for the follow-up control measures of salt reduction. This study found that the awareness rate of maximum daily salt intake and the behavior rate of salt reduction of Chinese adult residents was low, and nutrition education activities and targeted interventions should be enhanced, especially in rural areas, people with low education levels and low incomes.
Cross-sectional survey data for this study was obtained from the CCDNS in 2015, which used 298 surveillance points (counties or districts) across 31 provincial-level administrative divisions (PLADs) and a multistage stratified cluster randomized sampling method to select a national representative sample of households. Eligible residents aged 18 years old and above in the selected households were invited to participate by local CDCs. In a sample of the 88,250 households, 189,605 participants completed the survey, which yielded a 95.4% family response rate and a 94.9% individual response rate. After excluding 8,701 participants with incomplete data, 180,904 participants were included in this study. The study protocol was approved by the Ethical Committee of the National Center for Chronic and Non-Communicable Disease Control and Prevention of China CDC. All participants signed informed consent.
The CCDNS included face-to-face interviews, body measurements conducted by locally-trained personnel, and blood testing in the certified laboratories. The questionnaire related to this study included demographic characteristics (gender, age, education level, income, occupation, etc.), maximum daily salt intake recommended by “Dietary Guidelines for Chinese Residents”, salt reduction behaviors, and information on chronic diseases. The awareness rate of maximum daily salt intake was defined as the percentage of people who had heard the Dietary Guidelines for Chinese residents and could correctly answer the recommended maximum daily salt intake (6 g/d). The behavior rate of salt reduction was defined as the percentage of people self-reporting taking salt reduction measures. Hypertension was defined as systolic blood pressure (SBP) ≥140 mmHg and/or diastolic blood pressure (DBP) ≥90 mmHg, or those who had been diagnosed with hypertension by township (community) and above hospitals and took antihypertensive medicine in the 2 weeks before surveying.
All statistical descriptions were weighted to obtain nationally representative estimates. Population data from the National Bureau of Statistics in 2015 was used to adjust the post-stratification weights. Rao Scott chi-square test was used to compare the disordered categorical variables, and the logistic regression model was used to test the trend of ordinal categorical variables. Multivariable logistic regression models were used to explore the factors associated with being aware of maximum daily salt intake and salt reduction. All statistical analyses were performed using software SAS (version 9.4, SAS Institute, Inc. Cary, NC, USA), and p<0.05 was statistically significant.
A total of 180,904 participants were included in this study, including 84,407 men and 96,497 women, 73,738 in urban areas, and 107,166 in rural areas. In 2015, the awareness rate of maximum daily salt intake among Chinese adults aged 18 years old and above overall was 6.1% (95% CI: 5.2%–6.9%), males 5.4% (95% CI: 4.7%–6.2%), females 6.7% (95% CI: 5.7%–7.7%), urban residents 9.3% (95% CI: 7.7%–10.9%), and rural residents 2.6% (95% CI: 2.2%–3.0%). The awareness rates of the 30–39 age group (7.8%, 95% CI: 6.6%–9.0%), residents of the eastern region (7.6%, 95% CI: 5.9%–9.3%), retired residents (14.3%, 95% CI: 12.3%–16.2%) and hypertension group (6.4%, 95% CI: 5.5%–7.4%) were significantly higher than those of others residents (p<0.001) and tended to increase with an increase in education level, family per capita income, and high body mass index (BMI). (Table 1)
Characteristics Total Men Women Urban Rural N† Prevalence/%
(95% CI*)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)Total 180,904 6.1(5.2–6.9) 84,407 5.4(4.7–6.2) 96,497 6.7(5.7–7.7) 73,738 9.3(7.7–10.9) 107,166 2.6(2.2–3.0) Age (years) 18–29 15,881 6.2(5.2–7.2) 7,078 4.9(4.0–5.8) 8,803 7.6(6.3–8.9) 6,636 9.2(7.4–10.9) 9,245 2.6(2.0–3.2) 30–39 21,740 7.8(6.6–9.0) 9,704 6.3(5.1–7.5) 12,036 9.3(7.7–10.9) 9,415 10.5(8.3–12.7) 12,325 4.4(3.3–5.4) 40–49 39,965 6.5(5.5–7.5) 17,954 6.2(5.1–7.2) 22,011 6.8(5.7–7.8) 15,174 9.7(7.9–11.6) 24,791 3.1(2.5–3.7) 50–59 44,221 4.8(3.8–5.7) 20,354 4.6(3.7–5.5) 23,867 4.9(3.8–6.0) 17,702 8.2(6.4–10.0) 26,519 1.6(1.3–1.9) 60–69 40,093 4.6(3.6–5.5) 19,461 4.7(3.9–5.5) 20,632 4.5(3.3–5.6) 16,659 8.6(6.8–10.4) 23,434 1.4(1.0–1.8) 70+ 19,004 4.2(3.5–5.0) 9,856 5.2(4.2–6.1) 9,148 3.4(2.6–4.2) 8,152 8.4(6.9–9.9) 10,852 0.9(0.5–1.4) p value for trend <0.001 0.449 <0.001 0.130 <0.001 Geographic Location Eastern 67,378 7.6(5.9–9.3) 31,273 6.7(5.3–8.1) 36,105 8.5(6.5–10.6) 33,247 9.9(7.1–12.7) 34,131 4.1(3.1–5.1) Central 51,539 5.1(4.0–6.3) 24,131 4.6(3.5–5.8) 27,408 5.6(4.3–6.9) 21,038 8.9(6.6–11.2) 30,501 1.9(1.6–2.1) Western 61,987 4.7(3.6–5.8) 29,003 4.3(3.3–5.3) 32,984 5.1(3.7–6.5) 19,453 8.6(6.5–10.8) 42,534 1.7(1.2–2.3) p value for difference 0.002 0.007 0.003 0.727 <0.001 Education Primary or less 88,819 1.0(0.8–1.2) 35,105 1.1(0.9–1.4) 53,714 0.9(0.6–1.1) 24,514 1.8(1.3–2.3) 64,305 0.6(0.4–0.7) Junior High 55,243 4.2(3.6–4.8) 29,964 3.9(3.3–4.4) 25,279 4.6(3.9–5.3) 23,296 5.8(4.6–7.0) 31,947 2.8(2.3–3.2) Senior High 23,346 10.1(8.4–11.8) 12,796 8.1(6.5–9.7) 10,550 12.9(10.8–15.0) 14,555 11.8(9.2–14.4) 8,791 6.7(5.6–7.7) College or above 13,496 17.8(15.6–20.0) 6,542 14.1(12.2–15.9) 6,954 21.7(18.9–24.5) 11,373 18.3(15.9–20.7) 2,123 14.3(9.4–19.2) p value for trend <0.001 <0.001 <0.001 <0.001 <0.001 Family per capita income, CNY Q1 (<6,000) 45,278 2.7(2.1–3.2) 21,699 2.7(1.9–3.5) 23,579 2.6(2.1–3.2) 9,531 4.4(3.1–5.7) 35,747 2.0(1.5–2.5) Q2 (6,000–11,999) 38,741 4.3(3.7–4.9) 18,059 4.4(3.6–5.1) 20,682 4.3(3.5–5.0) 12,536 6.5(5.2–7.8) 26,205 2.7(2.3–3.2) Q3 (12,000–21,599) 36,932 7.2(6.2–8.1) 17,022 6.2(5.3–7.1) 19,910 8.2(7.1–9.4) 19,546 9.2(7.9–10.5) 17,386 3.7(3.0–4.4) Q4 (21,600+) 29,527 12.5(10.1–14.8) 13,780 10.4(8.5–12.3) 15,747 14.7(11.8–17.6) 21,114 14.4(11.4–17.3) 8,413 4.8(2.7–6.9) Don’t know/refused§ 30,426 4.1(2.7–5.6) 13,847 3.6(2.5–4.8) 16,579 4.7(2.8–6.6) 11,011 7.1(4.1–10.0) 19,415 1.6(1.2–1.9) p value for trend <0.001 <0.001 <0.001 <0.001 <0.001 Employment status Employed 130,625 6.1(5.3–6.9) 68,241 5.3(4.6–6.0) 62,384 7.1(6.0–8.2) 44,637 9.5(7.9–11.2) 85,988 2.8(2.4–3.3) Housework 25,112 2.2(1.7–2.7) 4,597 1.6(1.0–2.3) 20,515 2.3(1.8–2.8) 9,098 3.6(2.5–4.6) 16,014 1.2(0.8–1.6) Retired 16,606 14.3(12.3–16.2) 7,624 12.2(10.6–13.7) 8,982 16.0(13.6–18.5) 15,010 15.2(13.1–17.2) 1,596 4.8(2.4–7.3) Unemployed 8,561 5.6(4.0–7.2) 3,945 4.3(2.7–5.8) 4,616 6.9(4.8–9.0) 4,993 7.6(5.3–9.9) 3,568 2.1(1.3–2.9) p value for difference <0.001 <0.001 <0.001 <0.001 <0.001 Body weight status (BMI categories) Underweight, BMI<18.5 6,822 4.7(3.2–6.3) 2,986 2.8(1.4–4.2) 3,836 6.3(4.3–8.2) 2,177 7.4(4.1–10.7) 4,645 1.9(1.2–2.6) Normal weight,
BMI: 18.5–23.985,129 6.0(5.1–6.8) 40,103 4.4(3.9–5.0) 45,026 7.3(6.2–8.5) 31,491 9.7(8.2–11.2) 53,638 2.2(1.8–2.6) Overweight,
BMI: 24–27.963,232 6.1(5.2–7.0) 29,975 6.1(5.2–7.1) 33,257 6.1(5.2–7.1) 27,898 9.1(7.5–10.7) 35,334 2.9(2.3–3.5) Obesity, BMI≥28 25,721 6.8(5.5–8.0) 11,343 7.6(6.2–8.9) 14,378 5.8(4.3–7.3) 12,172 9.4(7.1–11.7) 13,549 3.6(2.9–4.2) p value for trend 0.014 <0.001 0.006 0.910 <0.001 Hypertension Yes 71,642 6.4(5.5–7.4) 35,181 5.3(4.5–6.0) 36,461 7.5(6.3–8.7) 28,940 9.7(7.9–11.4) 42,702 2.8(2.3–3.2) No 109,262 5.2(4.4–5.9) 49,226 5.7(4.9–6.6) 60,036 4.4(3.7–5.1) 44,798 8.5(7.0–9.9) 64,464 2.2(1.8–2.6) p value for difference <0.001 0.207 <0.001 0.025 0.002 * CI=confidence interval.
† N=Number of participants.
§ Participants answering “don’t know or refuse” were not included in the trend test.Table 1. Awareness rate of the maximum daily salt intake among Chinese adults aged 18 years old and above — China, 2015.
In 2015, the behavior rate of salt reduction of Chinese adult residents was overall 37.3% (95% CI: 35.5%–39.1%), males 33.8% (95% CI: 32.1%–35.4%), females 40.9% (95% CI: 38.8%–43.0%), urban residents 44.6% (95% CI: 42.4%–46.7%), and rural residents 29.7% (95% CI: 27.6%–31.7%). In males or urban areas, the behavior rate of salt reduction of the 18–29 age group was significantly lower than that of other age groups (p<0.001), while in females or rural areas, there were no significant differences among different age groups. The behavior rate of salt reduction was higher in eastern regions, retired residents, the hypertension group, and people who knew the maximum daily salt intake and increased with an increase in education level, family per capita income, and BMI. (Table 2)
Characteristics Total Men Women Urban Rural N† Prevalence/%
(95% CI*)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)N† Prevalence/%
(95% CI)Total 180,904 37.3(35.5−39.1) 84,407 33.8(32.1−35.4) 96,497 40.9(38.8−43.0) 73,738 44.6(42.4−46.7) 107,166 29.7(27.6−31.7) Age (years old) 18−29 15,881 32.3(30.4−34.2) 7,078 27.4(25.1−29.6) 8,803 37.3(35.0−39.5) 6,636 36.0(33.6−38.5) 9,245 27.6(25.2−30.1) 30−39 21,740 39.6(37.2−42.0) 9,704 35.5(33.3−37.7) 12,036 43.8(40.8−46.9) 9,415 47.0(44.0−50.0) 12,325 30.1(27.9−32.4) 40−49 39,965 39.5(37.5−41.6) 17,954 36.9(34.9−38.9) 22,011 42.2(39.8−44.7) 15,174 48.0(45.4−50.7) 24,791 30.7(28.5−32.9) 50−59 44,221 38.8(36.8−40.8) 20,354 35.2(33.3−37.2) 23,867 42.5(40.2−44.7) 17,702 47.1(44.6−49.6) 26,519 31.2(28.9−33.5) 60−69 40,093 38.7(36.4−41.0) 19,461 35.5(33.2−37.8) 20,632 41.9(39.5−44.4) 16,659 48.3(45.7−51.0) 23,434 31.0(28.2−33.8) 70+ 19,004 35.9(32.6−39.2) 9,856 35.0(32.1−37.8) 9,148 36.7(32.5−40.8) 8,152 47.8(44.1−51.6) 10,852 26.3(22.7−30.0) p value for trend 0.001 <0.001 0.309 <0.001 0.448 Geographic Location Eastern 67,378 44.6(41.9−47.2) 31,273 40.7(38.1−43.2) 36,105 48.6(45.5−51.6) 33,247 49.2(45.8−52.6) 34,131 37.4(34.0−40.9) Central 51,539 33.2(30.3−36.1) 24,131 29.8(27.4−32.3) 27,408 36.6(33.1−40.0) 21,038 40.1(36.4−43.7) 30,501 27.4(24.3−30.5) Western 61,987 30.5(27.3−33.8) 29,003 27.4(24.4−30.5) 32,984 33.7(30.1−37.4) 19,453 39.7(35.4−43.9) 42,534 23.6(20.0−27.2) p value for difference <0.001 <0.001 <0.001 <0.001 <0.001 Education Primary or less 88,819 29.3(27.3−31.2) 35,105 25.5(23.8−27.3) 53,714 31.9(29.7−34.1) 24,514 36.3(33.4−39.2) 64,305 25.8(23.8−27.8) Junior High 55,243 36.4(34.5−38.4) 29,964 32.0(30.2−33.8) 25,279 41.9(39.5−44.4) 23,296 42.3(39.8−44.8) 31,947 31.2(28.9−33.5) Senior High 23,346 44.2(42.2−46.2) 12,796 39.7(37.8−41.7) 10,550 50.4(47.8−52.9) 14,555 48.2(45.4−51.1) 8,791 35.8(33.2−38.4) College or above 13,496 50.7(48.5−52.9) 6,542 46.1(43.2−49.0) 6,954 55.4(52.5−58.4) 11,373 51.4(49.0−53.8) 2,123 45.4(39.8−50.9) p value for trend <0.001 <0.001 <0.001 <0.001 <0.001 Family per capita income, CNY Q1 (<6,000) 45,278 30.1(27.8−32.5) 21,699 26.6(24.5−28.6) 23,579 33.7(30.8−36.5) 9,531 35.9(32.3−39.5) 35,747 27.9(25.2−30.6) Q2 (6,000−11,999) 38,741 34.8(32.7−36.9) 18,059 31.4(29.1−33.6) 20,682 38.2(35.9−40.5) 12,536 40.9(37.7−44.1) 26,205 30.4(28.1−32.6) Q3 (12,000−21,599) 36,932 41.9(39.7−44.2) 17,022 37.9(35.7−40.2) 19,910 46.1(43.1−49.1) 19,546 46.4(43.9−48.9) 17,386 34.4(31.7−37.1) Q4 (21,600+) 29,527 49.2(46.5−52.0) 13,780 45.0(42.3−47.6) 15,747 53.8(50.6−56.9) 21,114 52.0(48.6−55.4) 8,413 37.9(33.6−42.1) Don’t know/refused§ 30,426 30.7(27.7−33.7) 13,847 27.6(24.6−30.5) 16,579 33.6(30.0−37.3) 11,011 38.1(33.5−42.6) 19,415 24.1(21.5−26.8) p value for trend <0.001 <0.001 <0.001 <0.001 <0.001 Employment status Employed 130,625 36.4(34.4−38.3) 68,241 33.2(31.5−34.8) 62,384 40.4(38.0−42.8) 44,637 43.7(41.5−45.9) 85,988 29.3(27.3−31.4) Housework 25,112 35.9(33.1−38.8) 4,597 28.2(24.2−32.2) 20,515 37.4(34.6−40.3) 9,098 43.9(40.2−47.6) 16,014 30.3(26.8−33.8) Retired 16,606 57.2(54.2−60.3) 7,624 53.4(50.4−56.3) 8,982 60.6(57.1−64.0) 15,010 58.7(55.5−61.8) 1,596 42.3(34.6−50.1) Unemployed 8,561 34.9(31.5−38.2) 3,945 30.5(26.0−35.0) 4,616 38.9(35.6−42.3) 4,993 37.3(32.4−42.2) 3,568 30.5(26.5−34.5) p value for difference <0.001 <0.001 <0.001 <0.001 <0.001 Body weight status (BMI categories) Underweight, BMI<18.5 6,822 27.5(23.3−31.6) 2,986 23.2(18.3−28.2) 3,836 30.9(26.8−35.0) 2,177 31.8(23.0−40.5) 4,645 23.0(20.5−25.5) Normal weight, BMI:18.5−23.9 85,129 35.1(33.2−36.9) 40,103 29.5(28.0−31.0) 45,026 40.2(37.7−42.6) 31,491 42.3(39.9−44.6) 53,638 27.8(26.0−29.7) Overweight, BMI:24−27.9 63,232 40.0(37.9−42.1) 29,975 37.5(35.5−39.6) 33,257 42.9(40.4−45.4) 27,898 47.9(45.6−50.1) 35,334 31.4(28.9−34.0) Obesity, BMI≥28 25,721 42.0(39.5−44.5) 11,343 41.0(38.4−43.7) 14,378 43.0(40.0−46.0) 12,172 48.1(45.2−50.9) 13,549 34.5(31.1−38.0) p value for trend <0.001 <0.001 <0.001 <0.001 <0.001 Hypertension Yes 71,642 39.3(37.4−41.3) 35,181 37.4(35.4−39.3) 36,461 41.7(39.6−43.8) 28,940 47.6(45.4−49.8) 42,702 31.9(29.6−34.2) No 109,262 36.5(34.6−38.4) 49,226 32.1(30.5−33.7) 60,036 40.6(38.3−42.9) 44,798 43.4(41.1−45.7) 64,464 28.6(26.6−30.7) p value for difference <0.001 <0.001 0.214 <0.001 <0.001 Awareness of maximum daily salt intake Yes 9,335 71.8(69.0−74.7) 4,081 68.6(65.0−72.3) 5,254 74.4(71.3−77.6) 6,935 73.6(70.5−76.7) 2,400 28.7(26.7−30.8) No 171,569 35.1(33.4−36.8) 80,326 31.8(30.2−33.4) 91,243 38.5(36.5−40.5) 66,803 41.6(39.6−43.5) 104,766 65.0(60.3−69.7) p value for difference <0.001 <0.001 <0.001 <0.001 <0.001 * CI=confidence interval.
† N=Number of participants.
§ Participants answering “don’t know or refuse” were not included in the trend test.Table 2. Behavior rate of salt reduction among Chinese adults aged 18 years old and above — China, 2015.
Multivariate logistic regression models showed that age, sex, residential area, educational level, family per capita income, employment status, and BMI were related to the awareness of daily maximum salt intake and behavior of salt reduction. The awareness rate of daily maximum salt intake and behavior rate of salt reduction of high-income families were significantly higher than those of the low-income group, and retired people were higher than the employees. Regions and hypertension were not associated with awareness of maximum daily salt intake but were associated with salt reduction behaviors. There was a significant association between awareness of daily maximum salt intake and behavior of salt reduction (OR=3.20, 95% CI: 2.77–3.70). (Table 3)
Characteristics Awareness of maximum daily salt intake Behavior of salt reduction OR 95% CI* p value OR 95% CI p value Age (years) 18−29 Ref Ref 30−39 1.49 1.28−1.74 <0.001 1.42 1.31−1.55 <0.001 40−49 1.92 1.65−2.24 <0.001 1.61 1.48−1.76 <0.001 50−59 1.37 1.13−1.66 0.002 1.56 1.42−1.71 <0.001 60−69 1.93 1.54−2.42 <0.001 1.79 1.62−1.97 <0.001 70+ 1.90 1.52−2.39 <0.001 1.59 1.36−1.86 <0.001 Sex Men Ref Ref Women 1.60 1.46−1.75 <0.001 1.50 1.42−1.57 <0.001 Residence Urban Ref Ref Rural 0.67 0.51−0.87 0.003 0.75 0.67−0.84 <0.001 Geographic location Eastern Ref Ref Central 0.86 0.65−1.14 0.300 0.69 0.60−0.79 <0.001 Western 0.98 0.75−1.29 0.905 0.68 0.57−0.79 <0.001 Education Primary or less Ref Ref Junior high 4.66 3.81−5.69 <0.001 1.47 1.39−1.56 <0.001 Senior high 11.09 8.83−13.92 <0.001 1.85 1.69−2.02 <0.001 College or above 20.41 14.99−27.79 <0.001 2.16 1.91−2.43 <0.001 Family per capita income, CNY Q1 (<6,000) Ref Ref Q2 (6,000−11,999) 1.17 0.97−1.40 0.097 1.07 0.98−1.17 0.129 Q3 (12,000−21,599) 1.24 0.99−1.55 0.064 1.17 1.05−1.30 0.005 Q4 (21,600+) 1.41 1.08−1.84 0.011 1.20 1.05−1.37 0.009 Don’t know/refused 0.93 0.67−1.29 0.673 0.83 0.74−0.94 0.003 Employment status Employed Ref Ref Housework 0.58 0.48−0.70 <0.001 1.04 0.94−1.15 0.479 Retired 1.67 1.39−2.02 <0.001 1.35 1.19−1.53 <0.001 Unemployed 0.81 0.64−1.01 0.062 0.94 0.80−1.10 0.422 BMI categories Normal weight, BMI:18.5−23.9 Ref Ref Underweight, BMI<18.5 0.77 0.55−1.07 0.120 0.73 0.57−0.95 0.019 Overweight, BMI:24−27.9 1.05 0.95−1.15 0.361 1.18 1.13−1.23 <0.001 Obesity, BMI≥28 1.13 1.00−1.27 0.055 1.22 1.14−1.31 <0.001 Hypertension Yes Ref Ref No 0.95 0.86−1.05 0.324 0.90 0.86~0.94 <0.001 Awareness of maximum daily salt intake No − − − Ref Yes − − − 3.20 2.77−3.70 <0.001 Note: "−" means not applicable.
Abbreviations: Ref=reference
* CI=confidence interval.Table 3. Associations between factors and awareness rate of the maximum daily salt intake and behavior of salt reduction among Chinese adults aged 18 years old and above — China, 2015.
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This study showed that the awareness rate of maximum daily salt intake and behavior rate of salt reduction among adult residents in China was quite low, especially in rural areas and people with low education levels. In this study, only 6.1% of Chinese adults knew of the daily maximum salt intake, and 37.3% of Chinese adults took salt reduction measures. Previous studies have shown that reducing salt intake can decrease blood pressure, reduce the incidence of hypertension, and the burden of cardiovascular events (3). Therefore, it is necessary to take measures to increase the awareness rate of daily maximum salt intake and reduce salt intake in China.
Previous studies had shown that the awareness of daily maximum salt intake varied greatly between different countries or regions. A sample survey of 5 PLADs in rural northern China showed that 5.0% of 5,050 elderly Chinese residents knew of the daily maximum salt intake (4). Claro et al. showed that the awareness rate of daily maximum salt intake was 6.3% in Argentina and 54.1% in Canada (5). Differences in results between studies may be related to the education level and economic development in the regions and countries. This study found that social inequality had a negative impact on salt-related awareness and behavior. Awareness of maximum daily salt intake and the behavior rate of salt reduction was higher in people living in the urban areas, or with higher education level, or with high family income per capita, or who have retired, which was largely consistent with the results from the previous studies (6). Lower awareness rates in rural areas may have been due to lower levels of education, poorer development of health education, and less developed health promotion campaigns.
This study showed that about one-third of the population took measures to control their salt intake, which was lower than that in 2010 (42.2%) (7). This showed that bad habits formed in the long term are difficult to change in a short term, and salt reduction requires a long time and sustained efforts (7). This study found that the awareness rate of daily maximum salt intake and the salt reduction behavior rate among the hypertension population was significantly higher than that of the non-hypertension population, which was consistent with the result of a previous study (8). This may be because people who knew they have high blood pressure were more concerned about their health and thus controlled their salt intake or took salt reduction measures under the guidance of doctors. Previous studies showed that salt-related knowledge could affect salt reduction behaviors (8). In this study, the behavior rate of salt reduction was significantly higher in those who knew the maximum salt intake than those who did not. This study showed that improving knowledge is a critical step in behavioral changes, and indicating educational activities in nutrition may be essential for the implementation of good behavior (6).
Individuals, businesses, and governments all play an important role in reducing salt. At the national level, China has conducted policies to reduce people’s salt intake, including “China Healthy Lifestyle for All” and the “National Nutrition Week”. Moreover, China has carried out various regional salt reduction programs, such as the Shandong Ministry of Health Action on Salt Reduction and Hypertension (9). In China, salt intake comes mainly from added salt or soy sauce in home cooking, but salt in processed foods also makes up a large portion (10). Therefore, it is particularly important to strengthen the salt-related knowledge and salt reduction technology of families and inform residents of maximum daily intake of salt and improve awareness of hidden salt in food and to inform the public of ways to control salt in cooking. Government departments should formulate policies related to salt reduction and strengthen the assessment and evaluation of the corresponding control measures.
This study was subject to at least one limitation. The results of the survey were self-reported and may be subject to a favorable response bias, which may overestimate or underestimate their actual salt reduction behavior, or a recall bias. Furthermore, the questionnaire did not include salt reduction attitudes, so the relationship between salt reduction attitude and behaviors could not be studied.
In conclusion, this study provides a nationwide report on population-based salt-related knowledge and behavior. This study found that the awareness rate of maximum daily salt intake and behavior rate of salt reduction of Chinese adult residents were low. Chinese residents require further nutrition education to better understand the recommended maximum daily salt intake and take further salt reduction measures, particularly in rural areas or people with low education levels, or with low incomes.
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