ObjectiveThe gold standard method for measuring population sodium intake is based on a 24 h urine collection carried out in a random population sample. However, because participant burden is high, response rates are typically low with less than one in four agreeing to provide specimens. At this low level of response it is possible that simply asking for volunteers would produce the same results.SettingLithgow, New South Wales, Australia.ParticipantsWe randomly selected 2152 adults and obtained usable 24 h urine samples from 306 (response rate 16%). Specimens were also collected from a further 113 volunteers. Estimated salt consumption and the costs for each strategy were compared.ResultsThe characteristics of the ‘random’ and ‘volunteer’ samples were moderately different in mean age 58 (SD 14.6 vs 49(17.7) years, respectively; p<0.001) as well as self-reported alcohol use, tobacco use, history of hypertension and prescription drug use (all p<0.04). Overall crude mean 24 h urinary salt excretion was 8.9(3.6) g/day in the random sample vs 8.5(3.3) g/day for the volunteers (p=0.42). Corresponding age-adjusted and sex-adjusted estimates were 9.2(3.3) and 8.8(3.4) g/day (p=0.29). Estimates for men 10.3(3.8) vs 9.6(3.3) g/day; (p=0.26) and women 7.6(3) vs 7.9(3.2) g/day; (p=0.43) were also similar for the two samples, as was salt excretion across age groups (p=0.72). The cost of obtaining each 24 h urine sample was two times greater for the random compared to volunteer samples ($A62 vs $A31).ConclusionsThe estimated salt consumption derived from the two samples was comparable and was not substantively different to estimates obtained from other surveys. In countries where salt is pervasive and cannot easily be avoided, estimates of consumption obtained from volunteer samples may be valid and less costly.

AimSalt reduction efforts usually have a strong focus on consumer education. Understanding the association between salt consumption levels and knowledge, attitudes and behaviours towards salt should provide insight into the likely effectiveness of education-based programs.MethodsA single 24-hour urine sample and a questionnaire describing knowledge, attitudes and behaviours was obtained from 306 randomly selected participants and 113 volunteers from a regional town in Australia.ResultsMean age of all participants was 55 years (range 20–88), 55% were women and mean 24-hour urinary salt excretion was 8.8(3.6) g/d. There was no difference in salt excretion between the randomly selected and volunteer sample. Virtually all participants (95%) identified that a diet high in salt can cause serious health problems with the majority of participants (81%) linking a high salt diet to raised blood pressure. There was no difference in salt excretion between those who did 8.7(2.1) g/d and did not 7.5(3.3) g/d identify that a diet high in salt causes high blood pressure (p = 0.1). Nor was there a difference between individuals who believed they consumed “too much” 8.9(3.3) g/d “just the right amount” 8.4(2.6) g/d or “too little salt” 9.1(3.7) g/d (p = 0.2). Likewise, individuals who indicated that lowering their salt intake was important 8.5(2.9) g/d vs. not important 8.8(2.4) g/d did not have different consumption levels (p = 0.4).ConclusionThe absence of a clear association between knowledge, attitudes and behaviours towards salt and actual salt consumption suggests that interventions focused on knowledge, attitudes and behaviours alone may be of limited efficacy.

BackgroundSalt reduction is a public health priority but there are few studies testing the efficacy of plausible salt reduction programs.MethodsA multi-faceted, community-based salt reduction program using the Communication for Behavioral Impact framework was implemented in Lithgow, Australia. Single 24-h urine samples were obtained from 419 individuals at baseline (2011) and from 572 at follow-up (2014). Information about knowledge and behaviors relating to salt was also collected.ResultsSurvey participants were on average 56 years old and 58 % female. Mean salt intake estimated from 24-h urine samples fell from 8.8 g/day (SD = 3.6 g/day) in 2011 to 8.0 (3.6) g/day in 2014 (−0.80, 95 % confidence interval −1.2 to −0.3;p < 0.001). There were significant increases in the proportion of participants that knew the recommended upper limit of salt intake (18 % vs. 29 %; p < 0.001), knew the importance of salt reduction (64 % vs. 78 %; p < 0.001) and reported changing their behaviors to reduce their salt intake by using spices (5 % vs. 28 %; p < 0.001) and avoiding eating out (21 % vs. 34 %; p < 0.001). However, the proportions that checked food labels (30 % vs. 25 %; p = 0.02) fell, as did the numbers avoiding processed foods (44 % vs. 35 %; p = 0.006). Twenty-six percent reported using salt substitute at the end of the intervention period and 90 % had heard about the program. Findings were robust to multivariable adjustment.ConclusionsImplementation of this multi-faceted community-based program was associated with a ~10 % reduction in salt consumption in an Australian regional town. These findings highlight the potential of well-designed health promotion programs to compliment other population-based strategies to bring about much-needed reductions in salt consumption.Clinical trial registrationNCT02105727.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-3064-3) contains supplementary material, which is available to authorized users.

BackgroundExcess dietary salt is a leading risk for health. Multiple health, government, industry and community organisations have identified the need to reduce consumption of dietary salt. This project seeks to implement and evaluate a community-based salt reduction intervention.MethodsThe study comprises a baseline assessment followed by a targeted intervention and then an evaluation of efficacy. The study location is Lithgow, a regional town in New South Wales, Australia. The salt reduction intervention is based upon the Communication for Behavioural Impact framework which utilises an integrated communication model to enact community advocacy and impact by providing tools that enable the translation of knowledge into behavioural change. The duration of the intervention will be between 6 and 12 months. The primary evaluation will be through measurement of 24-hr urinary sodium excretion in independent population samples aged > 20 years, drawn before and after the intervention period. The study is designed to detect a difference in mean sodium excretion of 0.7 grams per day or greater with 80% power and p = 0.05.DiscussionThis study will provide a robust evaluation of the effectiveness of a community-based intervention seeking to reduce dietary salt intake using the Communication for Behavioural Impact framework. The results will provide important new evidence to inform the design and implementation of current and future salt reduction policies in Australia. The results will also have important international implications because, following the recent World Health Organization recommendations for the control of non-communicable diseases, many countries are now seeking to achieve a reduction in average population salt consumption.Trial registrationClinicalTrials.gov, NCT02105727

Study of the composition and distribution of derived lithoclast and fossil suites collected from the Selsey, Barton and Becton Formations in Whitecliff Bay, Isle of Wight has enabled a detailed reconstruction of Mid-Late Eocene uplift of 500 m + on the northern limb of the Sandown Pericline. The stratigraphical distribution of clasts and fossils derived from older formations demonstrates the erosion of progressively older Eocene, Palaeocene and Cretaceous sediments during growth of the structure. The presence of delicate reworked fossils and clasts, together with limited palaeocurrent data support very local derivation from the south. The preservational state of the derived materials is used to identify the diverse processes of erosion and transport. Two phases of uplift (Lutetian, Bartonian), separated by a period of quiescence and peneplanation have been identified; rates of Eocene uplift of about 100 m Ma – 1 are postulated to have taken place.