An evaluation of salt intake and iodine nutrition in a rural and urban area of the Côte d’Ivoire

Abstract

Objective: To evaluate the habitual salt intake of individuals living in the Côte d’Ivoire, and to monitor the iodine nutrition of adults, schoolchildren and pregnant women one year after implementation of a universal salt iodisation programme.

Design: A three day weighed food records with estimation of food intake from a shared bowl based on changes on body weight, determination of sodium and iodine concentrations in 24 h (24 h) urine samples from adults, and determination of urinary iodine in spot urines from schoolchildren and pregnant women.

Setting: A large coastal city (Abidjan) and a cluster of inland villages in the northern savannah region of the Côte d’Ivoire.

Subjects: For the food records: 188 subjects (children and adults) in the northern villages; for the 24 h urine collections: 52 adults in Abidjan and 51 adults in the northern villages; for the spot urine collections: 110 children and 72 pregnant women in Abidjan and 104 children and 66 pregnant women in the north.

Main results: From the food survey data in the north, the total mean salt intake (s.d.) of all age groups and the adults was estimated to be 5.7 g/d (±3.0), and 6.8 g/d (±3.2), respectively. In the 24 h urine samples from adults, the mean sodium excretion was 2.9 g/d (±1.9) in the north and 3.0 g/d (±1.3) in Abidjan, corresponding to an intake of 7.3–7.5 g/d of sodium chloride. In the north the median 24 h urinary iodine excretion in adults was 163 μg/d, and the median urinary iodine in spot urines from children and pregnant women was 263 μg/l and 133 μg/l, respectively. In contrast, in Abidjan the median 24 h urinary iodine was 442 μg/d, with 40% of the subjects excreting >500 μg/d, and the median urinary iodine in spot urines from children and pregnant women was 488 μg/l and 364 μg/l, respectively. Nearly half of the children in Abidjan and 32% of the pregnant women were excreting >500 μg/l.

Conclusion: Based on the estimates of salt intake in this study, an optimal iodine level for salt (at the point of consumption) would be 30 ppm. Therefore the current goals for the iodised salt programme—30–50 ppm iodine—appear to be appropriate. However, in adults, children and pregnant women from Abidjan, high urinary iodine levels—levels potentially associated with increased risk of iodine-induced hyperthyroidism—are common. These results suggest an urgent need for improved monitoring and surveillance of the current salt iodisation programme in the Côte d’Ivoire.

Sponsorship: Swiss Federal Institute of Technology, Zurich, Switzerland.