Constituent analysis of iodine intake in Armenia

Abstract

Objective: We sought to assess the universal salt iodization (USI) strategy in Armenia by characterizing dietary iodine intake from naturally occurring iodine, salt-derived iodine in processed foods and salt-derived iodine in household-prepared foods.

Design: Using a cross-sectional cluster survey model, we collected urine samples which were analysed for iodine and sodium concentrations (UIC and UNaC) and household salt samples which were analysed for iodine concentration (SI). SI and UNaC data were used as explanatory variables in multiple linear regression analyses with UIC as dependent variable, and the regression parameters were used to estimate the iodine intake sources attributable to native iodine and iodine from salt in processed foods and household salt.

Setting: Armenia is naturally iodine deficient; in 2004, the government mandated a USI strategy.

Subjects: We recruited school-age children (SAC), pregnant women (PW) and non-pregnant women of reproductive age (WRA).

Results: From thirteen sites covering all provinces, sufficient urine and table salt samples were obtained from 312 SAC, 311 PW and 332 WRA. Findings revealed significant differences between groups: contribution of native iodine ranged from 81% in PW to 46% in SAC, while household salt-derived iodine contributed from 19% in SAC to 1% in PW.

Conclusions: Differences between groups may reflect differences in diet. In all groups, household and processed food salt constituted a significant part of total iodine intake, highlighting the success and importance of USI in ensuring iodine sufficiency. There appears to be leeway to reduce salt intake without adversely affecting the iodine status of the population in Armenia.

Keywords: Armenia; Iodine nutrition; Population iodine intake apportionment; Universal salt iodization.

Fig. 1

(colour online) Map of study sites in Armenia with provinces labelled

Fig. 2

Calculation scheme for the estimation of 24 h sodium excretion for a given urine sample from corresponding sodium and creatinine concentration measurements using the tool of separately established 24 h creatinine reference values (UNaC, spot urinary sodium concentration; UCr, spot urinary creatinine concentration; Cr Refence, 24 h creatinine reference value; see Table 1). Adapted from Johner et al.^{( 19 )}

Fig. 3

(colour online) Constituent components (, iodine from table salt; , iodine from salt used in processed foods; , native iodine) of urinary iodine concentration (UIC) according to population group (SAC, school-age children; PW, pregnant women; WRA, non-pregnant women of reproductive age) Armenia, September–November 2016

Fig 4

(colour online) Histogram of estimated sodium excretion per 24 h among non-pregnant women of reproductive age, Armenia, September–November 2016