Associations between dietary salt, potassium and blood pressure in?South African adults: WHO SAGE Wave 2 Salt & Tobacco

摘要

Abstract Background & aims In June 2016, South Africa implemented legislation mandating maximum sodium levels in a range of processed foods with a goal of reducing population salt intake and disease burden from hypertension. Our aim was to explore the relationship between salt and blood pressure (BP) in a subsample of the World Health Organization Study on global AGEing and adult health (SAGE) Wave 2 before implementation of legislation in South Africa. Methods & results Blood pressure (BP) was measured in triplicate (n?=?2722; median age 56 years; 33% male) and 24-h?urine collected in a nested subsample (n?=?526) for sodium, potassium and creatinine analysis. Hypertension prevalence was 55% in older adults (50-plus years) and 28% in younger adults (18–49 years). Median salt intake (6.8?g/day) was higher in younger than older adults (8.6?g vs 6.1?g/day; p??0.001), and in urban compared to rural populations (7.0?g vs 6.0?g/day; p?=?0.033). Overall, 69% of participants had salt intakes above 5?g/day. Potassium intakes were generally low (median 35?mmol/day) with significantly lower intakes in rural areas and older adults. Overall, 91% of adults failed to meet the daily potassium recommendation of 90?mmol/d. Salt intakes above 5?g/day, and to a greater extent, a dietary sodium-to-potassium (Na:K) ratio above 2?mmol/mmol, were associated with significantly steeper regression slopes of BP with age. Conclusion These preliminary results indicate that high dietary Na:K ratio may lead to a greater increase in BP and hypertension risk with age. Interventions to increase potassium intakes alongside sodium reduction initiatives may be warranted. Highlights ? South Africa's new health legislation aims to reduce sodium intake & hypertension rates. ? Pre-legislation data shows most adults (69%) consume more than 5?g salt/day. ? Additionally, 91% of adults fail to meet daily dietary potassium requirements. ? Sodium-to-potassium ratio had a greater impact than salt on age