Abstract
Objectives
Many studies have shown that socio-economic status (SES) contributes to health inequalities, with nutrition as one of the major risk factors. Iodine intake entirely depends on external sources, and deficiencies are known to be more prevalent in lower social groups, especially in countries with limited access to iodized salt. This study aimed to determine the influence of SES on iodine status and iodine availability from household salt in North Macedonia.
Methods
Using cluster sampling, 1,200 children were recruited, and 1,191 children participated (response rate: 99.2%). Iodine status was assessed through urinary iodine concentration (UIC), and iodine availability through iodine content in household salt requested from participants. SES was assessed using standardized Family Affluence Score (FAS).
Results
No statistically significant correlation was found between FAS and iodine in salt. Median regression revealed no significant associations of middle vs. low FAS (β=0.00; 95%-confidence interval (CI)=[−0.61, 0.62]; p=0.999) or high vs. low affluence (β=0.48; 95% CI=[−1.37, 0.41]; p=0.291) with iodine content in household salt. UIC levels were significantly lower in middle FAS children compared to low FAS children (β=−16.4; 95% CI=[−32.3, −0.5]; p=0.043). No statistically significant differences in UIC were found between children with high and low affluence (β=−12.5; 95% CI=[−35.5, 10.5]; p=0.287), possibly due to lowered statistical power for this comparison.
Conclusions
Universal salt iodization (USI) proves to be a cost-effective measure for appropriate iodine intake in healthy children and adults, irrespective of their social status. It can thus be concluded that USI contributes to reducing health inequalities related to iodine status among population of different social strata.
Funding source: European Commission
Award Identifier / Grant number: Horizon2020 grant agreement no. 634453
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Research funding: This work was supported by the EUthyroid project, financially supported by the European Commission’s Horizon2020 research and innovation programme [grant agreement no. 634453]. The funding organisation played no role in the study design; in the collection, analysis and interpretation of dat; in the writing of the report; or in the decision to submit the report for publication.
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: Authors state no conflict of interest.
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Informed consent: Informed consent was obtained from a parent or a guardian of every participating children included in this study.
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Ethical approval: The study received ethical approval from the Ethics Committee at the Faculty of Medicine, University “Ss. Cyril and Methodius” in Skopje, Macedonia.
References
1. Darmon, N, Drewnowski, A. Does social class predict diet quality? Am J Clin Nutr 2008;87:1107–17. https://doi.org/10.1093/ajcn/87.5.1107.Search in Google Scholar
2. Monsivais, P, Aggarwal, A, Drewnowski, A. Are socio-economic disparities in diet quality explained by diet cost? J Epidemiol Community Health 2012;66:530–5. https://doi.org/10.1136/jech.2010.122333.Search in Google Scholar
3. Novakovic, R, Cavelaars, A, Geelen, A, Nikolic, M, AltabaII, Vinas, BR, et al.. Socio-economic determinants of micronutrient intake and status in Europe: a systematic review. Publ Health Nutr 2014;17:1031–45. https://doi.org/10.1017/s1368980013001341.Search in Google Scholar
4. Vinas, BR, Barba, LR, Ngo, J, Gurinovic, M, Novakovic, R, Cavelaars, A, et al.. Projected prevalence of inadequate nutrient intakes in Europe. Ann Nutr Metab 2011;59:84–95. https://doi.org/10.1159/000332762.Search in Google Scholar
5. Walker, SP, Wachs, TD, Gardner, JM, Lozoff, B, Wasserman, GA, Pollitt, E, et al.. Child development: risk factors for adverse outcomes in developing countries. Lancet 2007;369:145–57. https://doi.org/10.1016/s0140-6736(07)60076-2.Search in Google Scholar
6. Adler, NE. Health disparities: taking on the challenge. Perspect Psychol Sci 2013;8:679–81. https://doi.org/10.1177/1745691613506909.Search in Google Scholar PubMed
7. Pearce, EN, Andersson, M, Zimmermann, MB. Global iodine nutrition: where do we stand in 2013? Thyroid 2013;23:523–8. https://doi.org/10.1089/thy.2013.0128.Search in Google Scholar PubMed
8. Cribb, VL, Jones, LR, Rogers, IS, Ness, AR, Emmett, PM. Is maternal education level associated with diet in 10-year-old children? Publ Health Nutr 2011;14:2037–48. https://doi.org/10.1017/s136898001100036x.Search in Google Scholar PubMed
9. Navia, B, Ortega, RM, Requejo, AM, Perea, JM, Lopez-Sobaler, AM, Faci, M. Influence of maternal education on food consumption and energy and nutrient intake in a group of pre-school children from Madrid. Int J Vitam Nutr Res 2003;73:439–45. https://doi.org/10.1024/0300-9831.73.6.439.Search in Google Scholar PubMed
10. Buzina, R. Ten years of goiter prophylaxis in Croatia, Yugoslavia. Am J Clin Nutr 1970;23:1085–9. https://doi.org/10.1093/ajcn/23.8.1085.Search in Google Scholar PubMed
11. Karanfilski, B, Sestakov, G, Loparska, S, Miceva-Ristevska, S, Serafimov, N, Tadzer, I, et al.. Reevaluation of the results of iodine prophylaxis in eradication of endemic goiter in Macedonia. Med Pregl 1993;46(1 Suppl):77–9.Search in Google Scholar
12. Milevska-Kostova, N, Karanfilski, B, Knowles, J, Codling, K, Lazarus, JH. Modelling the contribution of iodised salt in industrially processed foods to iodine intake in Macedonia. PLoS One 2022;17:e0263225. https://doi.org/10.1371/journal.pone.0263225.Search in Google Scholar
13. Karanfilski, B, Bogdanova, V, Vaskova, O, Loparska, S, Miceva-Ristevska, S, Sestakov, G, et al.. The Correction of iodine deficiency in Macedonia. Skopje: UNICEF Office: National Committee for Iodine Deficiency 2004:1–214.10.1515/JPEM.2003.16.7.1041Search in Google Scholar
14. WHO. Assessment of iodine deficiency disorders and monitoring their elimination. Geneva: World Health Organisation; 2007.Search in Google Scholar
15. Machado, A, Lima, L, Mesquita, RBR, Bordalo, AA. Improvement of the Sandell-Kolthoff reaction method (ammonium persulfate digestion) for the determination of iodine in urine samples. Clin Chem Lab Med 2017;55:e206–8. https://doi.org/10.1515/cclm-2016-1094.Search in Google Scholar
16. Caldwell, KL, Maxwell, CB, Makhmudov, A, Pino, S, Braverman, LE, Jones, RL, et al.. Use of inductively coupled plasma mass spectrometry to measure urinary iodine in NHANES 2000: comparison with previous method. Clin Chem 2003;49:1019–21. https://doi.org/10.1373/49.6.1019.Search in Google Scholar
17. Currie, C, Molcho, M, Boyce, W, Holstein, B, Torsheim, T, Richter, M. Researching health inequalities in adolescents: the development of the health behaviour in school-aged children (HBSC) family affluence scale. Soc Sci Med 2008;66:1429–36. https://doi.org/10.1016/j.socscimed.2007.11.024.Search in Google Scholar
18. Hobza, V, Hamrik, Z, Bucksch, J, De Clercq, B. The family affluence scale as an indicator for socioeconomic status: validation on regional income differences in the Czech republic. Int J Environ Res Publ Health 2017;14:1540. https://doi.org/10.3390/ijerph14121540.Search in Google Scholar
19. Currie, CE, Elton, RA, Todd, J, Platt, S. Indicators of socioeconomic status for adolescents: the WHO health behaviour in school-aged children survey. Health Educ Res 1997;12:385–97. https://doi.org/10.1093/her/12.3.385.Search in Google Scholar
20. Volzke, H, Craesmeyer, C, Nauck, M, Below, H, Kramer, A, John, U, et al.. Association of socioeconomic status with iodine supply and thyroid disorders in northeast Germany. Thyroid 2013;23:346–53. https://doi.org/10.1089/thy.2012.0416.Search in Google Scholar
21. Vitti, P, Delange, F, Pinchera, A, Zimmermann, M, Dunn, JT. Europe is iodine deficient. Lancet 2003;361:1226. https://doi.org/10.1016/s0140-6736(03)12935-2.Search in Google Scholar
22. Andersson, M, Karumbunathan, V, Zimmermann, MB. Global iodine status in 2011 and trends over the past decade. J Nutr 2012;142:744–50. https://doi.org/10.3945/jn.111.149393.Search in Google Scholar PubMed
23. Vanderpump, MP, Lazarus, JH, Smyth, PP, Laurberg, P, Holder, RL, Boelaert, K, et al.. Iodine status of UK schoolgirls: a cross-sectional survey. Lancet 2011;377:2007–12. https://doi.org/10.1016/s0140-6736(11)60693-4.Search in Google Scholar
24. Aghini-Lombardi, F, Vitti, P, Antonangeli, L, Fiore, E, Piaggi, P, Pallara, A, et al.. The size of the community rather than its geographical location better defines the risk of iodine deficiency: results of an extensive survey in Southern Italy. J Endocrinol Invest 2013;36:282–6. https://doi.org/10.1007/bf03347103.Search in Google Scholar
25. WHO. Urinary iodine concentrations for determining iodine status in populations. Geneva: World Health Organization; 2013.Search in Google Scholar
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