Environmental and human iodine and selenium status: lessons from Gilgit-Baltistan, North-East Pakistan

Ahmad, Saeed; Bailey, Elizabeth H.; Arshad, Muhammad; Ahmed, Sher; Watts, Michael J.; Stewart, Alex G.; Young, Scott D.

Abstract

Iodine and selenium deficiencies are common worldwide. We assessed the iodine and selenium status of Gilgit-Baltistan, Pakistan. We determined the elemental composition (ICP-MS) of locally grown crops (n = 281), drinking water (n = 82), urine (n = 451) and salt (n = 76), correcting urinary analytes for hydration (creatinine, specific gravity). We estimated dietary iodine, selenium and salt intake. Median iodine and selenium concentrations were 11.5 (IQR 6.01, 23.2) and 8.81 (IQR 4.03, 27.6) µg/kg in crops and 0.24 (IQR 0.12, 0.72) and 0.27 (IQR 0.11, 0.46) µg/L in water, respectively. Median iodised salt iodine was 4.16 (IQR 2.99, 10.8) mg/kg. Population mean salt intake was 13.0g/day. Population median urinary iodine (uncorrected 78µg/L, specific gravity-corrected 83µg/L) was below WHO guidelines; creatinine-corrected median was 114µg/L but was unreliable. Daily selenium intake (from urinary selenium concentration) was below theEAR in the majority (46–90%) of individuals. Iodine and selenium concentrations in all crops were low, but no health-related environmental standards exist. Iodine concentration in iodised salt was below WHO-recommended minimum. Estimated population average salt intake was above WHO-recommended daily intake. Locally available food and drinking water together provide an estimated 49% and 72% of EAR for iodine (95µg/day) and selenium (45µg/day), respectively. Low environmental and dietary iodine and selenium place Gilgit-Baltistan residents at risk of iodine deficiency disorders despite using iodised salt. Specific gravity correction of urine analysis for hydration is more consistent than using creatinine. Health-relevant environmental standards for iodine and selenium are needed.

Citation

Ahmad, S., Bailey, E. H., Arshad, M., Ahmed, S., Watts, M. J., Stewart, A. G., & Young, S. D. (2021). Environmental and human iodine and selenium status: lessons from Gilgit-Baltistan, North-East Pakistan. Environmental Geochemistry and Health, 43, 4665–4686. https://doi.org/10.1007/s10653-021-00943-w

• Journal Article Type: Article
• Acceptance Date: Apr 14, 2021
• Online Publication Date: May 7, 2021
• Publication Date: 2021-11
• Deposit Date: May 10, 2021
• Publicly Available Date: May 11, 2021
• Journal: Environmental Geochemistry and Health
• Print ISSN: 0269-4042
• Electronic ISSN: 1573-2983
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 43
• Pages: 4665–4686
• DOI: https://doi.org/10.1007/s10653-021-00943-w
• Keywords: Environmental Engineering; Geochemistry and Petrology; General Environmental Science; Water Science and Technology; Environmental Chemistry; General Medicine
• Public URL: https://nottingham-repository.worktribe.com/output/5521994
• Publisher URL: https://link.springer.com/article/10.1007%2Fs10653-021-00943-w