Background: individual preventive behaviors are one of the key measures needed to prevent the spread of COVID-19. This study sought to identify the factors associated with the adoption of COVID-19 preventive measures, focusing specifically on information sources. Methods: we conducted a nationally representative cross-sectional survey of 30,053 Japanese adults in February 2021. The survey asked about socioeconomic, health-related, and psychological characteristics, attitudes toward immunization, and the use of information sources regarding COVID-19. We have constructed multivariable logistic regression to estimate the factors associated with the adoption of three preventive measures: 3Cs avoidance, hand hygiene and respiratory hygiene. Results: socioeconomic variables, psychological variables, and the use of information sources are significantly associated with the adoption of preventive measures. The more information sources one uses, the more likely one is to adopt preventive measures. Trust in healthcare professionals is positively associated with adopting preventive measures. On the other hand, negative correlations between trust in social media and preventive behaviors were observed. Conclusions: encouraging access to multiple information sources, utilizing communication channels, and modifying messaging according to target groups are essential to promote COVID-19 preventive measures.

Objective This paper provides an in-depth examination of public attitudes towards salt reduction across seven culturally diverse countries: the USA, the UK, France, Japan, Indonesia, Thailand, and Brazil. Design Cross-sectional regression analysis with questionnaire data. Setting An analysis of questionnaire study in seven countries. Participants The study’s questionnaire collected responses from 7090 participants across seven countries with the mean age of respondents being 46.06 years (SD 16.96). The gender distribution encompassed 3473 men (49.12%), 3582 women (50.66%), 24 non-binary individuals (0.34%) and 11 who identified as ‘other’ (0.16%). Primary and secondary outcome measures Attitudes toward sodium reduction were measured on a seven-point Likert scale. Results Regression analysis revealed significant associations between attitudes towards sodium reduction and various factors across countries. Gender was a significant factor in France, with women showing less awareness than men (coefficient −0.123, 95% CI −0.237 to −0.008). Age was a significant factor in Japan and Thailand, with older generations exhibiting stronger awareness. Occupation was a significant factor in France (grocery, 0.678, 0.229 to 1.127) and Japan (food service, 0.792, 0.300 to 1.283). In France (0.090, 0.033 to 0.146) and Brazil (0.092, 0.040 to 0.144), attitudes towards reducing sugar intake were positively associated with sodium reduction attitudes. Government interventions showed varying impacts, with positive associations in Thailand (0.004, 0.001 to 0.008) and negative associations in France (−0.003 –0.005 to −0.000). Conclusion Our study reveals a complex array of factors shaping attitudes towards sodium reduction across seven countries. These findings support the need for nuanced, country-specific approaches in formulating sodium reduction strategies. Future research should validate these findings, explore further determinants and understand how attitudes translate into dietary behaviours.

Background: Globally, an estimated 1.4 billion people had hypertension in 2014, yet only just over 20% had controlled blood pressure, and about 580 million remained undiagnosed. Evidence indicates that salt substitutes facilitate meaningful blood-pressure reductions, yet their implementation remains restricted by social and healthcare constraints. The comparative effectiveness of alternative sodium-reduction interventions for elevated blood pressure remains unclear, limiting their introduction across diverse clinical and public health contexts. This study is registered with PROSPERO (CRD420251130153). Methods: We systematically searched PubMed, MEDLINE, and supplementary sources for randomised controlled trials (RCTs) published between 2000 and 2025. All behavioural sodium-reduction interventions among populations with elevated blood pressure, including hypertension, were included. The mean difference in systolic blood pressure (SBP) was the primary outcome, as evidence indicates that intensive control of SBP to levels below 120–130 mmHg is significantly associated with a reduced risk of major cardiovascular disease (CVD) and all-cause mortality. Network and subgroup pairwise meta-analyses were performed, with sensitivity analyses conducted to assess robustness of the findings and subgroup analyses used to explore clinical and public health factors influencing intervention effectiveness (clinical factors: blood pressure stage, trial duration, and medication status; public health factors: setting, implementation period, and country income level). Results: Of 10,404 records identified, 42 studies (46 trials, n = 46,771) were included. While the use of salt substitutes was ranked the most effective intervention in the network meta-analysis, with reductions of −6.78 mmHg (95% CI, −8.42, −5.14) compared to no intervention and −5.35 mmHg (95% CI, −7.89, −2.81) compared to conventional health education, self-monitoring devices and low-sodium diets, when combined with health education, demonstrated similar magnitudes of SBP reductions. Digital health education showed a larger point estimate for SBP reduction by −3.59 mmHg (95% CI −7.40 to 0.22) than conventional education (−1.43 mmHg; 95% CI −3.49 to 0.63), but both confidence intervals crossed zero, indicating no statistically significant difference. Subgroup analyses indicated that, except for trial duration, intervention setting, and country income level in specific intervention comparisons, clinical and public health factors did not generally account for differences in SBP reduction. No evidence of publication bias was observed, except between salt substitutes and no intervention and low-sodium diets and no intervention. Conclusions: Network meta-analysis ranked the use of salt substitutes as the most effective intervention, yet self-regulated interventions, such as low-sodium diets and self-monitoring devices, when combined with education-based sodium-reduction approaches, showed comparable point estimates for SBP reductions. Digital health education showed promise as a supportive adjunct to self-regulated interventions, although its effects were variable and require further quantification. These findings underscore the need for alternative sodium-reduction interventions supported by digital or conventional health education to improve blood pressure control. Health education on sodium reduction, including clinical counselling, should be viewed primarily as a complementary component that enhances other interventions.