Salt consumption by Australian adults: a systematic review and meta-analysis

OBJECTIVE: Salt reduction is a public health priority because it is a leading contributor to the global burden of disease. As in Australia there is uncertainty about the current level of salt intake, we sought to estimate current levels. STUDY DESIGN: Random effects meta-analysis of data from 31 published studies and one unpublished dataset that reported salt or sodium consumption by Australian adults on the basis of 24-hour urine collections or dietary questionnaires. DATA SOURCES: MEDLINE (via Ovid) and EMBASE (to August 2016). DATA SYNTHESIS: Thirty-one published studies and one unpublished dataset (1989-2015; 16 836 individuals) were identified. The mean weighted salt consumption estimated from 24-hour urine collections was 8.70 g/day (95% CI, 8.39-9.02 g/day); after adjusting for non-urinary salt excretion, the best estimate of salt intake in Australia is 9.6 g/day. The mean weighted intake was 10.1 g/day (95% CI, 9.68-10.5 g/day) for men and 7.34 g/day (95% CI, 6.98-7.70 g/day) for women. Mean weighted consumption was 6.49 g/day (95% CI, 5.94-7.03 g/day) when measured with diet diaries, 6.76 g/day (95% CI, 5.48-8.05 g/day) when assessed with food frequency questionnaires, and 6.73 g/day (95% CI, 6.34-7.11) when assessed by dietary recall. Salt intake had not decreased between 1989 and 2015 (R² = -0.02; P = 0.36). CONCLUSION: Salt intake in Australian adults exceeds the WHO-recommended maximum of 5 g/day and does not appear to be declining. Measuring salt intake with methods based on self-reporting can substantially underestimate consumption. The data highlight the need for ongoing action to reduce salt consumption in Australia and robust monitoring of population salt intake.