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Corresponding author. Department of Cardiovascular, Endocrine-metabolic Diseases and Aging, National Institute of Health, Via Giano della Bella 34, 00161, Rome, Italy.
Corresponding author. Department of Clinical Medicine and Surgery, Federico II University of Naples Medical School, Via S. Pansini 5, 80131, Naples, Italy.
In Italian adults a significant reduction in salt intake has occurred over 10 years.
•
This reduction was independent of gender, age, BMI category and educational levels.
•
The salt intake in Italy remains definitely higher than recommended by WHO.
•
Salt intake remains higher in men, in overweight/obese and less education persons.
Abstract
Background and aims
The WHO Global Action Plan for the Prevention of non-communicable diseases (NCDs) recommends a 30% relative reduction in mean population salt/sodium intake. The study assessed the trend in the habitual salt intake of the Italian adult population from 2008 to 2012 to 2018–2019 based on 24-h urinary sodium excretion, in the framework of the CUORE Project/MINISAL-GIRCSI/MENO SALE PIU’ SALUTE national surveys.
Methods and results
Data were from cross-sectional surveys of randomly selected age and sex–stratified samples of resident persons aged 35–74 years in 10 (out of 20) Italian Regions distributed in North, Centre and South of the Country. Urinary sodium and creatinine measurements were carried out in a central laboratory. The analyses included 942 men and 916 women examined in 2008–2012, and 967 men and 1010 women examined in 2018–2019. The age-standardized mean daily population salt (sodium chloride) intake was 10.8 g (95% CI 10.5–11.1) in men and 8.3 g (8.1–8.5) in women in 2008–2012 and respectively 9.5 g (9.3–9.8) and 7.2 g (7.0–7.4) in 2018–2019. A statistically significant (p<0.0001) salt intake reduction was thus observed over 10 years for both genders, and all age, body mass index (BMI) and educational classes.
Conclusions
The average daily salt intake of the Italian general adult population remains higher than the WHO recommended level, but a significant reduction of 12% in men and 13% in women has occurred in the past ten years. These results encourage the initiatives undertaken by the Italian Ministry of Health aimed at the reduction of salt intake at the population level.
]. Creating environmental conditions that favour sustainable healthy habits is a fundamental tool to prevent and control NCDs. The WHO Global NCDs Action Plan 2013–2020 focussed on nine global targets and indicated a roadmap of policies and interventions useful to meet the commitments on NCD prevention made at the United Nations General Assembly in 2011 and 2014 and included in the 2030 Agenda for Sustainable Development [
The Global Burden of Disease Risk Factors Collaboration estimated that 4.1 million annual deaths are attributable to excess salt/sodium intake mainly because of its impact on the incidence of hypertension, coronary heart disease and stroke [
GBD 2015 Risk Factors Collaborators Global, Regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.
WHO Prevention of recurrent heart attacks and strokes in low and middle income populations: evidence-based recommendations for policy makers and health professionals.
] and has been identified as one of the most cost-effective measures countries can take to improve population health. A 30% relative reduction in the mean population salt intake by 2025 was indicated as one of the nine NCD-related global targets [
In Italy, since 2008, the Ministry of Health, within the framework of the “Gaining Health: making healthy choices easy” strategic Programme for NCDs prevention, has launched specific initiatives, with the collaboration of the Interdisciplinary Working group for Salt Reduction in Italy (GIRCSI), aimed at the reduction excess salt intake [
]. Furthermore, the reduction in excessive salt consumption is one of the main objectives of the National Preventive Plan (NPP) 2014–2018, extended to 2019, pursued at the Regional and local level.
An assessment of the habitual salt intake was carried out in 2008–2012 in the Italian general population aged 35–74 years using 24-h urine collections obtained from the participants of the Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey (OEC/HES 2008–2012) within the CUORE Project [
For the Osservatorio Epidemiologico cardiovascolare/health examination survey research group. Cardiovascular health in Italy. Ten-year surveillance of cardiovascular diseases and risk factors: Osservatorio Epidemiologico cardiovascolare/health examination survey 1998-2012.
]. To evaluate the effectiveness of the salt reduction population strategy implemented by the Italian Ministry of Health in collaboration with non-governmental organizations, a further assessment of the adult population salt intake has been made in 2018–2019 (HES 2018–2019 – CUORE Project) to evaluate the trend in salt intake over the past ten years. Both studies were promoted and supported by the Italian Ministry of Health.
Methods
Study population
Habitual salt intake comparison between OEC/HES 2008–2012 and HES 2018–2019 data for the purpose of the present analysis included persons aged 35–74 years, residents in 10 Regions involved in both surveys: Lombardy, Piedmont, Liguria, Emilia Romagna, Tuscany, Lazio, Abruzzo, Basilicata, Calabria and Sicily.
From March 2008 to July 2012, the OEC/HES, within the CUORE Project, investigated randomly selected age and sex–stratified samples of 220 men and women aged 35–79 years per every 1.5 million residents in all Italian Regions. The participation rate of OEC/HES 2008–2012, defined as the number of persons who participated in the survey after receiving the invitation divided by the size of the eligible sample, was 53% [
For the Osservatorio Epidemiologico cardiovascolare/health examination survey research group. Cardiovascular health in Italy. Ten-year surveillance of cardiovascular diseases and risk factors: Osservatorio Epidemiologico cardiovascolare/health examination survey 1998-2012.
]. In this framework, for the assessment of the population salt intake, the MINISAL-GIRCSI Study and MENO SALE PIU’ SALUTE Study used for each Region a randomly selected subsample of 100 men and 100 women aged 35–74 years, stratified by age and sex, based on the WHO recommendation that a sample of 100–200 individuals is required to estimate sodium intake with a 95% confidence interval (CI) about the mean of consumption of ±12 mmol/day using a single 24-h urine collection [
The OEC/HES 2008–2012 was conducted by the Italian National Institute of Health (Istituto Superiore di Sanità – ISS) in collaboration with a national scientific association of cardiologists (ANMCO–Associazione Nazionale Medici Cardiologi Ospedalieri) and its foundation [Fondazione per il Tuo Cuore – Heart Care Foundation (HCF)]. The MINISAL-GIRCSI and MENO SALE PIU’ SALUTE studies were conducted by the ISS for the part referring to the adult population that is included in the present analysis, in collaboration with the Federico II University of Naples Department of Clinical and Experimental Medicine, which had the responsibility of the overall MINISAL-GIRCSI Study.
From April 2018 to December 2019, a new HES has been conducted by the ISS, which has included the assessment of the Italian general adult population salt intake carried out in collaboration with Federico II University of Naples Department of Clinical Medicine and Surgery. The new survey investigated randomly selected age and sex–specific samples of 100 men and 100 women aged 35–74 years resident in 10 Regions (out of 20) chosen in the North, Centre and South of Italy. The participation rate of HES 2018–2019 was 40%.
The 2008–2012 and 2018–2019 surveys were approved by the Ethical Committee of the ISS respectively on 11 November 2009 and 14 March 2018, and are recognized within the European Health Examination Survey collaboration [
Both surveys included a 24-h urine collection, a physical examination and the administration of a common face-to-face questionnaire to collect information on demographic characteristics, educational level, lifestyles (physical activity, smoking, alcohol consumption, salt consumption), pathological history, family history and drug treatments. Standardized methods were used in the collection and measurement following European Health Examination Survey (EHES) recommendations [
For the Osservatorio Epidemiologico cardiovascolare/health examination survey research group. Cardiovascular health in Italy. Ten-year surveillance of cardiovascular diseases and risk factors: Osservatorio Epidemiologico cardiovascolare/health examination survey 1998-2012.
] Persons were invited to enrol by postal letter and an information notice of the project made the participant informed about the research purposes and able to consciously sign an informed consent to participate.
To assess dietary salt intake, participants were asked to collect all urines they passed during a 24-h period starting from the second morning urine pass and ending with the first urine passed the following morning. They were provided with a SARSTED plastic container of 3 L with the addition of thymol to prevent bacterial growth. Once the collection was returned, the total volume of urine was recorded and urine specimens were extracted after shaking. The specimens were immediately frozen: during the HES 2008–2012, three of them were kept at −30 °C for the measurement of sodium and creatinine whereas another one was maintained at −80 °C in the biological bank of the ISS for future determinations; during the HES 2018–2019, one at −30 °C and two at −80 °C respectively. The response rates to the request to provide 24-h urine samples among those who participated in the surveys were 92% in 2008–2012 and 99% in 2018–2019.
The measurement of sodium and creatinine was performed for both surveys at Federico II University of Naples by the central laboratory of Department of Clinical and Experimental Medicine (later become Department of Clinical Medicine and Surgery). In each survey, both urinary sodium and creatinine concentrations were measured using an ABX Pentra 400 apparatus (HORIBA ABX, Rome, Italy) with an integrated ion-selective electrode (ISE) module. Sodium was measured by ion-selective electrode potentiometry using as urine-specific reference the Urichem Gold Bio Dev (Milan, Italy). Urinary creatinine was measured by a kinetic Jaffe’ reaction using as urine reference the Urichem Gold Bio Dev (Milan, Italy) in the 2008–2012 survey and the Low-and High Control ABX (Montpellier, France) in the 2018–2019 survey. Quality control data for the 2008–2012 survey were: accuracy −0.1% for sodium and −1.95% for creatinine, inter-assay variation coefficient 2.2% for sodium and 1.5% for creatinine and intra-assay variation coefficient 0.7% for sodium and 1.1% for creatinine. The respective data for the 2018–2019 survey were: accuracy −0.0% for sodium and −0.7% for creatinine, inter-assay variation coefficient 1.4% for sodium and 2.7% for creatinine and intra-assay variation coefficient 1.3% for sodium and 3.8% for creatinine. Pre-defined criteria for a high likelihood of incomplete urine collection were set as a 24-h urine volume below 500 ml or a creatinine content referred to body weight outside the range given by the population mean ± 2 standard deviations: based on these criteria, 122 participants were excluded from the analysis for the 2008–2012 and 104 participants for the 2018–2019 survey.
The persons’ weight and height were measured while they were clothed only in their underwear. A balance beam scale was used for weight measurements, and height was measured with a height rule. Educational level and salt related habits were investigated through a face-to-face standardized questionnaire. A complete description of standardized methods and procedures of the OEC/HES 2008–2012 has been provided apart [
For the Osservatorio Epidemiologico cardiovascolare/health examination survey research group. Cardiovascular health in Italy. Ten-year surveillance of cardiovascular diseases and risk factors: Osservatorio Epidemiologico cardiovascolare/health examination survey 1998-2012.
]. Similar procedures and methods were used for data collection in the HES 2018–2019 survey.
Statistical analysis
Sodium was expressed in millimoles as 24-h urinary excretion and was translated to salt intake in grams per day (1 mmol = 23 mg of sodium), following the WHO suggestion to deliver, as salt intake indicator, the age-standardized mean population intakes of salt expressed as g/day in order to allow comparisons among studies [
]. Sodium excretion (mmol) was multiplied by 23 to obtain sodium intake (g/day) which was further multiplied by 2.5 to obtain salt intake (g/day). For the assessment of this indicator, age-standardization was performed using the direct method referring to the age and sex–specific distributions of Italian adult population 2010 and 2019, respectively for OEC/HES 2008–2012 and HES 2018–2019 [
] the prevalence of 24-h sodium excretion lower than 85 mmol (corresponding to 5 g of salt) per day was calculated.
Salt intake was also assessed by four classes of age (35–44, 45–54, 55–64 and 65–74 years) and, for those with available information, by three classes of body mass index (BMI; weight in kilogram divided by height in square metres) (normal weight – BMI within 18.5–24.9 kg/m2, overweight BMI within 25.0–29.9 kg/m2 and obesity BMI ≥ 30 kg/m2) and two classes of educational level (higher education – high school or college, lower education – primary or middle school). The results are expressed as means and standard deviations for quantitative variables and prevalence for qualitative ones; the related 95% CIs are reported. The t-test for unpaired samples (for equal or unequal variance as appropriate) or analysis of variance (ANOVA) was used to assess differences between group means. The chi-square test was used to compare prevalence. Two-sided p-values less than 0.05 were considered statistically significant. Statistical analyses were performed using the SAS software, release 9.4 (SAS Institute Inc, Cary, NC).
Results
After the exclusions reported above due to possibly incomplete urine collections, 942 men and 916 women (mean age ± std.: men 54 ± 11 and women 55 ± 11) and 967 men and 1010 women (mean age ± std.: men 55 ± 11 and women 56 ± 11) were included in the analysis relative to the 2008–2012 and the 2018–2019 survey, respectively.
Similar mean levels of 24-h urine volume as well as crude- and weight-adjusted creatinine were found in the two surveys by age class and gender (Table S1). The mean level of crude urinary creatinine excretion was higher in men than in women within both periods in each age class (p-value<0.0001). Moreover, in both periods, a progressively lower crude- and weight-adjusted creatinine excretion rate was found with age (p-value<0.0001). A trend was also observed towards a higher urine volume with age (Table S1).
In the 2008–2012 survey, mean 24-h urinary sodium excretion was 186 mmol (95% CI 181–190) in men and 143 mmol (139–146) in women; in the 2018–2019 survey, the respective values were 164 (160–168) and 124 (121–127) (Fig. 1). The mean sodium excretion was significantly reduced from 2008 to 2012 to 2018–2019 in both men (−12%) and women (−13%) (p-value<0.0001); the reduction was statistically significant in all age classes (Table 1).
Figure 1Frequency distribution of 24-h urinary sodium excretion by gender and period in Italy. Men and women aged 35–74 years, CUORE Project health examination surveys 2008–2012 and 2018–2019.
Table 1Data on 24-h sodium excretion (mmol) by sex, age class and period in Italy. Men and women aged 35–74 years, CUORE Project health examination surveys 2008–2012 and 2018–2019.
Age class (years)
2008–2012
2018–2019
% mean diff
t-test p-value
n
mean
std
95% CI
ANOVA p-value
n
mean
std
95% CI
ANOVA p-value
MEN
0.4599
0.7640
35–44
235
185
72
176
194
228
162
66
154
171
−12
0.0004
45–54
238
191
68
182
199
232
167
63
159
176
−12
0.0001
55–64
240
187
75
178
197
266
163
60
156
170
−13
0.0001
65–74
229
180
68
172
189
241
162
59
155
170
−10
0.0023
WOMEN
0.1899
0.0936
35–44
220
143
56
135
150
213
121
47
115
127
−15
<0.0001
45–54
223
149
62
141
157
252
123
47
117
129
−17
<0.0001
55–64
241
141
50
135
148
275
130
55
124
137
−8
0.0156
65–74
232
138
54
131
145
270
121
46
115
126
−12
0.0002
t-test: normal standardized t-test for comparison between periods.
Italian Regions: Lombardy, Piedmont, Liguria, Emilia Romagna, Tuscany, Lazio, Abruzzo, Basilicata, Calabria and Sicily.
ANOVA: ANOVA to compare 24 h sodium excretion among age classes within the period.
The age-standardized mean population salt intake was 10.8 g (standard deviation 4.1; 95% CI 10.5–11.1) in men and 8.3 g (3.2; 8.1–8.5) in women in the 2008–2012 survey and 9.5 g (3.6; 9.3–9.8) in men and 7.2 g (2.8; 7.0–7.4) in women in the 2018–2019 survey; the reduction by period was equal to 1.3 g in men and 1.1 g in women (p < 0.0001 for both).
Frequency distributions of 24-h urinary sodium excretion are shown in Fig. 1. Sodium excretion was consistently higher in men than in women, with a difference of 23% (p-value< 0.0001) in 2008–2012 and 24% in 2018–2019 (p-value<0.0001). Within period, no statistically significant differences were found for the mean of 24-h urinary sodium excretion across age classes (ANOVA, Table 1).
In the 2008–2012 survey, 24-h sodium excretion was lower than 85 mmol per day, in 4% (95% CI 3–5%) of men and 15% (13–17%) of women; in the 2018–2019 survey significantly higher values of 9% (7–11%) and 23% (20–26%) were found for men and women (p-value<0.0001).
In both periods and genders, 24-h sodium excretion was significantly and directly associated with BMI classes and inversely associated with educational levels, independently of age (ANOVA within period – Table 2).
Table 2Data on 24-h sodium excretion (mmol) by sex, body mass index class, educational level and period in Italy. Men and women aged 35–74 years, CUORE Project health examination surveys 2008–2012 and 2018–2019.
2008–2012
2018–2019
% mean diff
t-test p-value
ANOVA between periods p-value
n
mean
std
95% CI
ANOVA within period p-value
n
mean
std
95% CI
ANOVA within period p-value
MEN
Body mass index
<0.0001
<0.0001
<0.0001
Normal weight
235
170
64
162
178
314
147
54
141
153
−14
<0.0001
Overweight
454
182
67
176
189
458
168
63
163
174
−8
0.0013
Obese
246
209
79
199
219
191
182
63
173
191
−13
0.0001
Education
0.0195
0.0003
<0.0001
Higher education
497
181
72
175
187
685
159
58
155
164
−12
<0.0001
Lower education
436
191
69
185
198
279
175
70
167
183
−9
0.0020
Period
<0.0001
WOMEN
Body mass index
<0.0001
<0.0001
<0.0001
Normal weight
361
129
49
124
134
443
114
45
110
119
−12
<0.0001
Overweight
299
143
51
138
149
299
130
52
124
136
−9
0.0017
Obese
246
161
64
153
169
250
135
50
129
141
−16
<0.0001
Education
0.0053
0.0063
<0.0001
Higher education
455
137
55
132
143
685
121
47
117
124
−12
<0.0001
Lower education
447
147
55
142
152
323
130
52
124
136
−11
<0.0001
Period
<0.0001
Body mass index was available in 941 men and 916 women for the 2008–2012 survey and 967 men and 1010 women for 2018–2019 survey.
Educational level was available in 933 men and 902 women for the 2008–2012 survey and 964 men and 1008 women for 2018–2019 survey.
t-test: normal standardize t-test for comparison between periods. ANOVA within period: ANOVA p-value of the corresponding variable to compare 24 h sodium excretion among age classes (35–44, 45–54, 55–64 and 65–74 years), body mass index classes and educational levels. ANOVA between periods: ANOVA p-value of the corresponding variable to compare 24 h sodium excretion among periods, age classes (35–44, 45–54, 55–64 and 65–74 years), body mass index classes and educational levels. ANOVA analyses were performed among those with BMI ≥ 18.5 kg/m2. Normal weight – body mass index-BMI within 18.5–24.9 kg/m2, overweight BMI within 25.0–29.9 kg/m2 and obesity BMI≥30 kg/m2. Higher education – high school or college; lower education – primary or middle school. Italian regions: Lombardy, Piedmont, Liguria, Emilia Romagna, Tuscany, Lazio, Abruzzo, Basilicata, Calabria and Sicily.
The statistically significant reduction of 24-h sodium excretion between 2008–2012 and 2018–2019 was consistent across BMI classes and educational levels, considered singly (t-test –Table 2) or together independently of age (period significance of ANOVA between periods – Table 2).
In both periods, some geographical differences were found for 24-h sodium excretion independently of age, BMI and educational classes (Table S2); no Region had mean levels within those recommended (lower than 85 mmol) (Table S2 and Fig. 2) but a trend to reduction was observed between the two surveys in all Regions (except for men in the Abruzzo Region) (Table S2).
Figure 2Mean of 24-h urinary sodium excretion by gender, period and Region in Italy. Men and women aged 35–74 years, CUORE Project health examination surveys 2008–2012 and 2018–2019.
A trend to an increased prevalence of healthy salt–related habits was also observed between 2008–2012 and 2018–2019: in the second survey there was a higher proportion of men and women who reportedly never or rarely add salt at table, who eat always or very often bread without salt and who taste as more salty the food consumed out of home (Fig. 3). Nevertheless, in the 2018–2019 survey as many as 80% of men and 77% of women declared to be not influenced from the salt content information on food labels while shopping (data not available in the 2008–2012 survey) (Fig. 3).
Figure 3Prevalence (%) of self-reported salt-related habits by gender and period in Italy. Men and women aged 35–74 years, CUORE Project health examination surveys 2008–2012 and 2018–2019.
The main finding of the present study is the observation of a significant reduction of the habitual salt intake in randomly selected samples of general adult population recruited in ten Italian Regions approximately ten years apart. The reduction was detected to different extents in almost all Regions and was consistent with respect to sex, age, BMI category and education level.
The second important finding however was that the average daily salt intake remains largely higher than the level recommended by WHO and taken as the Standard Dietary Target for the Italian population: this is also true in all the surveyed Regions, for both men and women, and all age classes, education levels and BMI categories.
A significant trend of habitual salt intake reduction had never been observed in Italy: previously available information on dietary salt intake from several local studies such as the 1976 study of households, the 1985–1987 Intersalt (Gubbio, Bassiano, Mirano, Naples), the 1991 and the 2002–2004 Olivetti Heart Study showed approximately similar levels, not far from those observed within the OEC/HES 2008–2012 survey, considering similar geographical areas [
Intersalt Cooperative Research Group Intersalt: an interna- tional study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion.
The average reduction in salt intake observed in adults within the HES 2018–2019 survey compared to the previous one (12% in men and 13% in women) is more than one-third of the 2025 WHO global target of a 30% relative reduction. The trend observed in our study is consistent with the trend to salt intake reductions recently reported for other countries, albeit with different methodologies for salt intake assessment. Thus, Slovenia (from 2007 to 2012), Turkey (from 2008 to 2012) and the UK (from 2001 to 2011) reported salt intake reductions of 9%, 17% and 15% respectively, based on 24-h urinary excretion [
]. Dietary surveys were used by France (1999.2007), Iceland (1999–2007) and Ireland (2001–2011), which reported reductions of 5%, 6% and 14%, respectively [
]. Among non-European countries, China (from 1991 to 2009), Japan (from 1997 to 2012), Korea (from 2005 to 2012) and South Korea (from 2010 to 2014) reported reductions of 29%, 23%, 14% and 20%, respectively [
Additional findings of the present study are the sex-related difference in salt intake and the statistical associations of salt intake with BMI and educational level. All these findings are confirmatory of previous evidence. The gender difference is likely explained by differences in food and energy intake between men and women. The association between sodium excretion and BMI was also found in the preliminary report on the MINISAL Study [
A positive association between dietary sodium intake and obesity and central obesity: results from the National Health and Nutrition Examination Survey 1999-2006.
]. A possible explanation in this case is that foods with high sodium content are also usually high in energy, such as fatty and highly processed foods [
The Three-Factor Eating Questionnaire, bodymass index, and responses to sweet and salty fatty foods: atwin study of genetic and environmental associations.
The inverse association between salt intake and educational level was already reported by the OEC/HES 2008–2012 survey on 20 Italian Regions, showing that social inequalities, including disparities in the educational level, explained the geographical variation in salt intake in our country [
]. This finding was consistent with evidence from a recent systematic review and meta-analysis that included cohorts from high-income countries of East Asia, Australia, North America, Europe and Latin America [
]. In this case too it is conceivable that less educated people consume relatively greater amounts of possibly cheaper fatty and highly processed foods with high sodium content and high caloric density [
]. It is also possible that the educational level impacts on the way people are responsive to health information with a greater propensity of more educated individuals to comply with nutritional advice. It is to be noted however that in our study the reduction in salt intake over the past 10 years was similar for higher and lower educational levels, with only a minor difference in men. These results may suggest that salt consumption among Italian adults benefited from preventive actions that have reached the population across the board, such as agreements between the Italian Ministry of Health and associations of artisan bakers and companies in the food industry aimed at reducing salt content in artisan and industrial bread and in some industrial products (pasta, rice, soups) and the actions developed by all the Italian Regions with the National Prevention Plan 2014–2019, recently renewed and strengthened for 2020–2025 [
]. The agreements provided for a relative reduction of the salt content of 10–15%, depending on products and association/manufactures. Initiatives included in the National Prevention Plan, such as local intersectoral agreements and information activities for the population and training for operators related to the food sector, were followed by specific monitoring systems of the Regional Prevention Plans. These preventive programmes have been supported by the advocacy actions and the educational campaigns promoted at regular intervals by scientific societies.
In accordance with the trend in salt intake, the findings of the questionnaire on the population's life style habits related to salt intake showed an overall substantial improvement, although it is a matter of concern the modest attention paid to food labels concerning the salt content of foods when shopping.
Strengths and limitations
Major strengths of our study are as follows: the use of the gold standard method for the assessment of salt intake at the population level; the good national coverage with enrolment of the study participants through random age and sex stratification in half of the Italian Regions distributed in Northern, Central and Southern Italy; the excellent compliance with the request to provide 24-h urines; the overall good quality of the urine collections as indicated by the large mean urinary volume and by the finding of the expected mean values for urinary creatinine with the physiological differences related to sex, age and body weight.
However, we acknowledge some study limitations which should be considered when interpreting our results. First, because of the choice of urban districts for the random selection of the study participants in both surveys, the results may not be representative of the habits of populations living in rural areas. The participation rates to the surveys were lower than desirable, yet consistent with lower contact rates occurring in more highly urbanized areas and with the decreasing trend of participation observed in health examination surveys in other European countries [
]. The cross-sectional design of the study does not allow to assess causality of the associations between salt intake and BMI or educational level. The use of a single 24-h urine collection does not allow to accurately assess the individual salt intake due to the well-known large day-to-day variation in sodium excretion: however, it is sufficient for the assessment of salt intake in adequately sized population groups. There were differences in the educational level distribution between the two surveys, which are consistent with the increase in secondary and tertiary education assessed in adults from 2008 to 2017 by the Italian National Institute of Statistics [
]. There was also some difference in the BMI distribution. Nevertheless, these differences cannot have affected our major findings because, both in men and women, the amount of salt reduction was similar by BMI classes and educational levels. Moreover, the reduction of mean salt intake between periods was statistically significant when adjusted by BMI class and educational level. Finally, the salt intake monitoring was not extended to the younger age classes.
Conclusions
In conclusion, this comparison of 24-h urinary sodium excretion in two independent samples of Italian adult population, carried out in 10 Regions approximately 10 years apart from each other, showed a significant and substantial reduction in salt intake. This reduction was independent of gender, age, BMI category and educational level and met more than one-third of the 30% reduction target indicated in the WHO Global Action Plan 2013–2020.
This notwithstanding, the study indicated that the average salt intake in Italy remains definitely higher than the level recommended by WHO for both genders, all Regions and every class of age, BMI and educational level. Mean levels of salt intake were higher in men than in women, in those with overweight and obesity compared with normal-weight people, and in less educated compared with more educated individuals, confirming the important role of social inequalities.
Although these results need confirmation through further systematic and periodic monitoring, they have major public health implications in as much as they encourage the initiatives undertaken by the Italian Ministry of Health in collaboration with non-governmental organizations and in particular with the scientific societies in order to reduce salt intake at the population level through the “Gaining Health: making healthy choices easy” Programme and the National Prevention Plan. The attainment of this initial success in the contrast to a major causal factor of NCDs should prompt further actions to lower the amount of salt in the food supply, to generate knowledge and improve people behaviours through educational campaigns targeting also children and adolescents, to change the food environment and promote social norms so that people demand and gain greater control over their salt consumption. As suggested by the WHO and in accordance with the Italian Ministry of Health population strategy developed since 2008, regular surveillance is needed to make sure that strategies are appropriately targeted and changes can be measured over time.
Funding
The Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey OEC/HES 2008–2012 within the CUORE Project was funded by the Italian Ministry of Health (MoH), the Associazione Nazionale Medici Cardiologi Ospedalieri (ANMCO), the Fondazione per il Tuo cuore onlus (Heart Care Foundation – HCF) and the Joint Action of the European Health Examination Survey; the OEC/HES 2008–2012 included the MINISAL Study and part of the MENO SALE PIU’ SALUTE Study, promoted and funded by the MoH – National Center for Disease Prevention and Control (CCM). The HES 2018–2019 within the CUORE Project was promoted and funded by the MoH – CCM for activities related to the CCM 2017 project – Central Actions Area – entitled “Monitoring of the average daily consumption of sodium in the Italian population”. The OEC/HES 2008–2012 and HES 2018–2019 was also funded by the Italian National Institute of Health (Istituto Superiore di Sanità – ISS) through permanent staff salary and some travels refund.
Author contributions
CD participated in the study conception and design, managed the data collection and quality control, performed data analysis, interpreted results, drafted the manuscript and contributed to the management and storage of urine samples; CL contributed to the data collection, to quality control, to the management and the storage of urine samples and critically revised the manuscript; OR and RI performed the laboratory measurements, contributed to the data quality control and critically revised the manuscript; DM performed information technology services, contributed to the data collection and quality control and critically revised the manuscript; ADL contributed to data collection and quality control and critically revised the manuscript; EP contributed to data collection and critically revised; BB contributed to data collection and critically revised; FV contributed to information technology services and critically revised the manuscript; SV, FG, MMG, GO critically revised the manuscript; DG participated in the study conception, scientifically supported the studies and critically revised the manuscript; PB scientifically supported the studies and critically revised the manuscript; SG participated in the study conception and design, managed the data collection and quality control, contributed to the management and storage of urine samples and critically revised the manuscript; LP contributed to the storage of urine samples and critically revised the manuscript; PS participated in the study conception and design, was responsible for the laboratory measurements and data quality control, interpreted results and critically revised the manuscript. All authors have read and approved the final version of this manuscript for submission.
Declaration of competing interest
Authors have nothing to disclose.
Acknowledgments
Research Group of Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey (OEC/HES) 2008–2012 within the CUORE Project for the National Institute of Health (Istituto Superiore di Sanità – ISS): Luigi Palmieri (coordinator), Chiara Donfrancesco (coordinator), Simona Giampaoli (former coordinator), Cinzia Lo Noce, Serena Vannucchi, Anna Di Lonardo, Francesco Dima (former). Research group of the CUORE Project OEC/HES 2008–2012 for Associazione Nazionale Medici Cardiologi Ospedalieri/Health Care Foundation (ANMCO/HCF): Michele Massimo Gulizia, Furio Colivicchi and Andrea Di Lenarda (coordinators), Diego Vanuzzo (former coordinator), Domenico Gabrielli, Giuseppe Di Pasquale, Aldo Pietro Maggioni, Gian Francesco Mureddu, Carmine Riccio, Marino Scherillo, Stefano Urbinati, Pompilio Faggiano. Local coordinators of the OEC/HES 2008–2012 participating centers: Diego Vanuzzo (Centro di Prevenzione Cardiovascolare ASS 4 “Medio Friuli”, Udine); Licia Iacoviello (Centro di ricerca e formazione ad alta tecnologia nelle scienze biomediche Giovanni Paolo II, Università Cattolica, Campobasso); Federico Vancheri (Ospedale S. Elia, Caltanissetta); Carlo Alberto Goldoni (Dipartimento di sanità pubblica, Azienda USL, Modena); Carmelo Antonio Caserta (Associazione calabrese di epatologia, Cittanova – Reggio Calabria); Antonio Lopizzo (Ospedale San Carlo, Potenza); Natalino Meloni (USL 4, Loceri – Nuoro); Marinella Gattone (Fondazione S. Maugeri, Veruno – Novara); Giuseppe Salamina (SC Centro controllo malattia, ASL TO1, Torino); Alessandro Boccanelli (Ospedale San Giovanni Addolorata, Roma); Roberto Amici (Ospedale Santa Maria della Pietà, Camerino -Macerata); Gianfranco Alunni (Ospedale SantaMaria della Misericordia, Azienda Ospedaliera, Perugia); Giuseppe Favretto (Ospedale rabilitativo di alta specializzazione, Motta di Livenza – Treviso); Mariapiera Vettori (Azienda ULSS 13 del Veneto, Noale – Venezia);Marino Scherillo (Azienda Ospedaliera G. Rummo, Benevento); Pompilio Faggiano (Azienda Ospedaliera Spedali Civili, Brescia); Maria Teresa La Rovere (Fondazione Salvatore Maugeri, Istituto di riabilitazione, Montescano – Pavia); Maria Luisa Biorci (ASL 3 Genovese- PO “La Colletta”, Arenzano – Genova); Pasquale Caldarola (Cardiologia, Ospedale di Terlizzi, Centro servizi territoriali della città, Bitonto – Bari); Giovanni Menegoni (Azienda provincial per i servizi sanitari di Trento, Presidio ospedaliero, Borgo Valsugana – Trento); Rosa Maria Teresa Cristaudo (Azienda USL della Valle d’Aosta, Aosta); Andrea Zipoli (Azienda USL 11, Ospedale San Giuseppe, Empoli – Firenze); Paolo Michele Accettura (Laboratorio analisi, Ospedale San Camillo, Atessa – Chieti). Administrative staff of the ANMCO/HCF: Giulia Salone, Angela Petrucci, Monica Nottoli; and to Laura Bellicini and to L Bellicini, consultant lawyer of the ANMCO-HCF. Fondazione IRCCS, Istituto nazionale dei tumori, Milano: Vittorio Krogh, Sara Grioni. Research Group MINISAL-GIRCSI and MENO SALE PIU′ SALUTE: Pasquale Strazzullo, Ornella Russo, Lanfranco D'Elia, Roberto Iacone, Renato Ippolito, Enrico Agabiti-Rosei, Angelo Campanozzi, Marina Carcea, Ferruccio Galletti, Licia Iacoviello, Luca Scalfi, Alfonso Siani, Daniela Galeone, Chiara Donfrancesco, Simona Giampaoli. CARHES Research Group: Luca De Nicola, Chiara Donfrancesco, Roberto Minutolo, Cinzia Lo Noce, Luigi Palmieri, Amalia De Curtis, Licia Iacoviello, Carmine Zoccali, Loreto Gesualdo, Giuseppe Conte, Diego Vanuzzo, Simona Giampaoli. Research Group of the Health Examination Survey (HES) 2018–2019 within the CUORE Project: Chiara Donfrancesco (coordinator), Luigi Palmieri, Cinzia Lo Noce, Daniela Minutoli, Anna Di Lonardo, Elisabetta Profumo, Brigitta Buttari, Serena Vannucchi, Simona Giampaoli (former coordinator) (Italian National Institute Health -Istituto Superiore di Sanità, ISS). Local referents of HES 2018–2019 partecipating centers: Luigi Dell’Orso and Alessandro Grimaldi (Ospedale San Salvatore, L'Aquila); Nicola Giordano (ASL – Azienda Sanitaria Locale di Potenza, Potenza); Carmelo Caserta (Centro di Medicina Solidale – Associazione Calabrese di Epatologia, Reggio Calabria); Alessandra Fabbri (Casa della Salute AUSL RE, Montecchio Emilia); Fabrizio Ciaralli (Casa della Salute S. Caterina della Rosa, Rome); Fiorella Bagnasco (Municipality of Arenzano, Arenzano – Genova); Giuliana Rocca (ATS Bergamo); Giuseppe Salamina (ASL Città di Torino, Torino); Pietro Modesti (Università di Firenze, Florence); Federico Vancheri and Giulio Geraci (Ospedale S. Elia, Caltanissetta). Also we would to thank for HES 2018–2019: Anna Rita Ciccaglione, Cinzia Marcantonio, Roberto Bruni (ISS), Emanuele Bottosso and Anna Acampora (as trainee medical doctor at ISS), Giulia Cairella (ASL Roma 2, SINU) and Municipality of Potenza. Italian Ministry of Health: Daniela Galeone, Paolo Bellisario, Giovanna Laurendi, Bianca Maria Polizzi. European Health Examination Survey, Reference Centre: Hanna Tolonen, Kari Kuulasmaa, Paivikki Koponen, Johan Heldan, Susanna Conti, Georg Alfthan. Administrative staff of the ISS: Claudia Meduri, Tiziana Grisetti, Matilde Bocci, Gabriella Martelli, Valerio Occhiodoro, Maria Grazia Carella, Francesca Romana Meduri.
We acknowledge all persons who decided to participate in the OEC/HES 2008–2012 and HES 2018–2019 surveys.
Appendix A. Supplementary data
The following are the Supplementary data to this article:
Global, Regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.
Prevention of recurrent heart attacks and strokes in low and middle income populations: evidence-based recommendations for policy makers and health professionals.
For the Osservatorio Epidemiologico cardiovascolare/health examination survey research group. Cardiovascular health in Italy. Ten-year surveillance of cardiovascular diseases and risk factors: Osservatorio Epidemiologico cardiovascolare/health examination survey 1998-2012.
A positive association between dietary sodium intake and obesity and central obesity: results from the National Health and Nutrition Examination Survey 1999-2006.
The Three-Factor Eating Questionnaire, bodymass index, and responses to sweet and salty fatty foods: atwin study of genetic and environmental associations.
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