Lebanese children are iodine deficient and urinary sodium and fluoride excretion are weak positive predictors of urinary iodine

Abstract

Purpose

To assess iodine and fluoride status among Lebanese children.

Methods

A nationally representative cross-sectional study of 6- to 10-year-old schoolchildren was conducted using multistage cluster sampling. Spot urine samples were collected from 1403 children, and urinary iodine, fluoride, creatinine and sodium levels were measured. Salt samples from markets (n = 30) were tested for iodine concentration by titration.

Results

Median urinary iodine concentration was 66.0 µg/l, indicating mild deficiency, and almost 75 % of Lebanese children had a urinary iodine concentration (UIC) <100 µg/l. UIC was higher among children from private schools and in areas of higher socioeconomic status. Most salt samples were fortified at levels far below the legislated requirement, and 56 % of samples contained less than 15 ppm iodine. Fluoride-to-creatinine ratio (F/Cr) was 0.250 (0.159–0.448) mg/g. There were weak positive correlations between UIC and urinary sodium (r 2 = 0.039, P value <0.001) and UIC and urinary fluoride (r 2 = 0.009, P value <0.001).

Conclusions

Lebanese elementary school children are iodine deficient due to inadequately iodized salt. The weak correlation between UIC and urinary sodium suggests most dietary iodine does not come from iodized salt. The poor correlation between UIC and urinary fluoride suggests that fluoride intake is not affecting iodine metabolism. Efforts are needed in Lebanon to improve industry compliance with salt fortification through improved monitoring and enforcement of legislation.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2

References

  1. 1.

    Andersson M, Karumbunathan V, Zimmermann MB (2012) Global iodine status in 2011 and trends over the past decade. J Nutr 142:744–750

    CAS  Article  Google Scholar 

  2. 2.

    World Health Organization (2007) Assessment of iodine deficiency disorders and monitoring their elimination: a guide for programme managers. World Health Organization, United Nations Children’s Fund, International Council for Control of Iodine Deficiency definition, Geneva

    Google Scholar 

  3. 3.

    Aburto N, Abudou M, Candeias V, Wu T, World Health Organization (2014) Effect and safety of salt iodisation to prevent iodine deficiency disorders: a systematic review with meta-analyses. World Health Organization, Geneva

    Google Scholar 

  4. 4.

    Bougma K, Aboud FE, Harding KB, Marquis GS (2013) Iodine and mental development of children 5 years old and under: a systematic review and meta-analysis. Nutrients 5:1384–1416

    CAS  Article  Google Scholar 

  5. 5.

    Zimmermann MB, Boelaert K (2015) Iodine deficiency and thyroid disorders. Lancet Diabetes Endocrinol 3:286–295

    CAS  Article  Google Scholar 

  6. 6.

    Herter-Aeberli I, Cherkaoui M, El Ansari N, Rohner R, Stinca S, Chabaa L, Von Eckardstein A, Aboussad A, Zimmermann MB (2015) Iodine supplementation decreases hypercholesterolemia in iodine-deficient, overweight women: a randomized controlled trial. J Nutr 145:2067–2075

    CAS  Article  Google Scholar 

  7. 7.

    World Health Organization (2004) Iodine status worldwide: WHO global database on iodine deficiency. World Health Organization, Geneva

    Google Scholar 

  8. 8.

    Cowan J, Najjar S, Sabry Z, Tannous R, Simaan F (1965) Some further observations on goiter in Lebanon. Am J Clin Nutr 17:164–170

    CAS  Google Scholar 

  9. 9.

    Cowan J, Kassab G, Silahian A, Shadarevian S (1966) Iodine intake and excretion in three different areas of Lebanon. J Med Liban 19:213–223

    CAS  Google Scholar 

  10. 10.

    Najjar SS, Woodruff CW (1963) Some observations on goiter in Lebanon. Am J Clin Nutr 13:46–54

    CAS  Google Scholar 

  11. 11.

    Ministry of Public Health of Lebanon (1997) UNICEF. Evaluation studies of the IDD programme in Lebanon. Ministry of Public Health, Beirut (Ref 3222)

    Google Scholar 

  12. 12.

    Ministry of Health of Lebanon, UNICEF, WHO, American University of Beirut (1994) IDD survey in Lebanon, 1993-final report. Ministry of Health, Beirut (Ref 485)

    Google Scholar 

  13. 13.

    Doumit M, Doughan B (2002) La santé bucco-dentaire des écoliers au Liban. Cahiers d’études et de recherches francophones. Santé 12:223–228

    Google Scholar 

  14. 14.

    Ge Y, Ning H, Wang S, Wang J (2005) Comet assay of DNA damage in brain cells of adult rats exposed to high fluoride and low iodine. Fluoride 38:209

    CAS  Google Scholar 

  15. 15.

    Jooste P, Weight M, Kriek J, Louw A (1999) Endemic goitre in the absence of iodine deficiency in schoolchildren of the Northern Cape Province of South Africa. Eur J Clin Nutr 53:8–12

    CAS  Article  Google Scholar 

  16. 16.

    Trivedi M, Verma R, Chinoy N, Patel R, Sathawara N (2007) Effect of high fluoride water on intelligence of school children in India. Fluoride 40:178–183

    Google Scholar 

  17. 17.

    El Mallah C, Ghattas H, Shatila D, Francis S, Merhi K, Hlais S, Toufeili I, Obeid O (2015) Urinary magnesium, calcium, and phosphorus to creatinine ratios of healthy elementary school Lebanese children. Biol Trace Elem Res 1–7. doi:10.1007/s12011-015-0484-3

  18. 18.

    Wang G, Zhou R, Wang Z, Shi L, Sun M (1999) Effects of storage and cooking on the iodine content in iodized salt and study on monitoring iodine content in iodized salt. Biomed Environ Sci 12:1–9

    Google Scholar 

  19. 19.

    Skeaff S, Thomson C, Gibson R (2002) Mild iodine deficiency in a sample of New Zealand school children. Eur J Clin Nutr 56:1169–1175

    CAS  Article  Google Scholar 

  20. 20.

    Lee J, Kim JH, Lee S-Y, Lee JH (2014) Iodine status in Korean preschool children as determined by urinary iodine excretion. Eur J Nutr 53:683–688

    CAS  Article  Google Scholar 

  21. 21.

    Pardede LV, Hardjowasito W, Gross R, Dillon DH, Totoprajogo OS, Yosoprawoto M, Waskito L, Untoro J (1998) Urinary iodine excretion is the most appropriate outcome indicator for iodine deficiency at field conditions at district level. J Nutr 128:1122–1126

    CAS  Google Scholar 

  22. 22.

    Andersen S, Karmisholt J, Pedersen KM, Laurberg P (2008) Reliability of studies of iodine intake and recommendations for number of samples in groups and in individuals. Br J Nutr 99:813–818

    CAS  Google Scholar 

  23. 23.

    Fuge R (2013) Soils and iodine deficiency. Essentials of Medical Geology. Springer, Berlin, pp 417–432

    Book  Google Scholar 

  24. 24.

    Knudsen N, Bülow I, Laurberg P, Ovesen L, Perrild H, Jørgensen T (2003) Low socio-economic status and familial occurrence of goitre are associated with a high prevalence of goitre. Eur J Epidemiol 18:175–181

    CAS  Article  Google Scholar 

  25. 25.

    Hynes KL, Blizzard CL, Venn AJ, Dwyer T, Burgess JR (2004) Persistent iodine deficiency in a cohort of Tasmanian school children: associations with socio-economic status, geographical location and dietary factors. Aust N Z J Public Health 28:476–481

    Article  Google Scholar 

  26. 26.

    Poland PAII (1999) Issues of IDD Newsletter. Young 15(4):105

    Google Scholar 

  27. 27.

    Section UN, Division UP, Communications UDo (2008) Sustainable elimination of iodine deficiency: progress since the 1990 World summit for children. UNICEF

  28. 28.

    Zimmermann MB, Wegmüller R, Zeder C, Torresani T, Chaouki N (2004) Rapid relapse of thyroid dysfunction and goiter in school-age children after discontinuation of salt iodization. Am J Clin Nutr 79:642–645

    CAS  Google Scholar 

  29. 29.

    Azizi F, Mehran L, Sheikholeslam R, Ordookhani A, Naghavi M, Hedayati M, Padyab M, Mirmiran P (2008) Sustainability of a well-monitored salt iodization program in Iran: marked reduction in goiter prevalence and eventual normalization of urinary iodine concentrations without alteration in iodine content of salt. J Endocrinol Invest 31:422–431

    CAS  Article  Google Scholar 

  30. 30.

    Alsanosy RMA, Gaffar AM, Khalafalla HE, Mahfouz MS, Zaid AN, Bani IA (2012) Current iodine nutrition status and progress toward elimination of iodine deficiency disorders in Jazan, Saudi Arabia. BMC Public Health 12:1006

    Article  Google Scholar 

  31. 31.

    Carvalho AL, de Souza Meirelles CJC, Oliveira LA, Costa TMB, Navarro AM (2012) Excessive iodine intake in school children. Eur J Nutr 51:557–562

    CAS  Article  Google Scholar 

  32. 32.

    Andersson M, de Benoist B, Rogers L (2010) Epidemiology of iodine deficiency: salt iodisation and iodine status. Best Pract Res Clin Endocrinol Metab 24:1–11

    CAS  Article  Google Scholar 

  33. 33.

    Bürgi H, Siebenhüner L, Miloni E (1984) Fluorine and thyroid gland function: a review of the literature. Klin Wochenschr 62:564–569

    Article  Google Scholar 

  34. 34.

    Zohouri F, Swinbank C, Maguire A, Moynihan P (2006) Is the fluoride/creatinine ratio of a spot urine sample indicative of 24-h urinary fluoride? Community Dent Oral Epidemiol 34:130–138

    CAS  Article  Google Scholar 

  35. 35.

    Petersen PE, Baez R, Marthaler T (2014) Basic methods for assessment of renal fluoride excretion in community prevention programmes for oral health. World Health Organization, Geneva

  36. 36.

    Rugg-Gunn A, Villa A, Buzalaf M (2011) Contemporary biological markers of exposure to fluoride. Monogr Oral Sci 22:37–51

    Article  Google Scholar 

  37. 37.

    Villa A, Anabalon M, Zohouri V, Maguire A, Franco A, Rugg-Gunn A (2010) Relationships between fluoride intake, urinary fluoride excretion and fluoride retention in children and adults: an analysis of available data. Caries Res 44:60–68

    CAS  Article  Google Scholar 

  38. 38.

    Akpata ES, Behbehani J, Akbar J, Thalib L, Mojiminiyi O (2014) Fluoride intake from fluids and urinary fluoride excretion by young children in Kuwait: a non-fluoridated community. Community Dent Oral Epidemiol 42:224–233

    Article  Google Scholar 

  39. 39.

    García-Hoyos F, Cardososilva C, Barbería E (2014) Renal excretion of fluoride after fluoride mouth rinses in children. Eur J Paediatr Dent 15:35–38

    Google Scholar 

  40. 40.

    Day T, Powell-Jackson P (1972) Fluoride, water hardness, and endemic goitre. Lancet 299:1135–1138

    Article  Google Scholar 

  41. 41.

    Doumit M, Doughan B, Baez R (2004) Oral health programme in Lebanon: technical resistance provided for development of baseline studies for salt fluoridation. Ministry of Public Health, Lebanese University, World Health Organization, Beirut

    Google Scholar 

  42. 42.

    Hector F, Maria AA, Margaret P, Anthony V, Fatima R-S (2009) Fluoride intake and urinary fluoride excretion in children attending a daycare center in Maracay, Aragua state, Venezuela. J Dent Oral Hyg 1:027–035

    CAS  Google Scholar 

  43. 43.

    Republic of Lebanon, Ministry of Foreign Affairs (2001) National report on follow-up to the world summit for children. Beirut

Download references

Acknowledgments

This work was funded by the University Research Board (URB) and Iodine Global Network (IGN), and both institutions had no direct or indirect involvements in this project.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Omar Obeid.

Ethics declarations

Integrity of research and reporting

The study protocol was approved by the Institutional Review Board of the American University of Beirut.

Conflict of interest

The authors declare that they have no conflict of interest.

Informed consent

All subjects gave their informed consent prior to their inclusion in the study.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Ghattas, H., Francis, S., El Mallah, C. et al. Lebanese children are iodine deficient and urinary sodium and fluoride excretion are weak positive predictors of urinary iodine. Eur J Nutr 56, 749–755 (2017). https://doi.org/10.1007/s00394-015-1120-x

Download citation

Keywords

  • Urinary iodine excretion
  • Urinary fluoride
  • Iodine/creatinine ratio
  • Fluoride/creatinine ratio
  • Sodium/creatinine ratio
  • Lebanon