Iodine is an important micronutrient required for the synthesis of thyroid hormones which is critical for proper development of the fetal brain. As foetal thyroid hormone production depends on maternal iodine levels [12], this study sought to investigate the UIC in pregnant women at Kissi the Central Region of Ghana.
The measurement of urinary iodine (UI) provides an accurate approximation of dietary iodine intake in view of the fact that the majority of iodine ingested is excreted via the urine. Urine iodine concentration is thus a reliable estimate of the amount of iodine intake and by extension of iodine deficiency [5]. This study found 42.5Â % prevalence of iodine deficiency in pregnant women in the study population, suggesting that this at-risk group and their unborn children are still in danger of iodine deficiency disorder (IDD). Recent studies in the UK and Europe found that even a mild iodine deficiency during pregnancy led to defective neurodevelopment that negatively impacted the intelligence quotient (IQ) and cognitive functions of such children [13, 14]. Therefore, the high prevalence of iodine insufficiency reported in this study suggests that urgent national measures are required to correct the iodine insufficiency in pregnant women in these communities. The findings in this study also suggests that the high prevalence of iodine insufficiency may be due to non-compliance with the use of iodized salt. This is particularly so considering that none of the participants on iodized salt suffered from severe or moderate iodine deficiency, whereas a total of 65Â % of the participants using non-iodized salt had either severe or moderate iodine deficiency. This is in line with the WHO/UNICEF Joint Committee on Health policy which recommended that universal salt iodization (USI) was the most cost-effective means to eradicate iodine insufficiency [15].
By using UIC in school-aged children (SAC), Andersson et al., previously found a 40Â % prevalence of iodine insufficiency in an African population [1]. Although we used UIC in pregnant women in this study, the 42.5Â % prevalence estimated in this study suggests a good correlation between the median UIC in SAC, and in adults, in a population that primarily uses iodized salt as the source of dietary iodine, as is the case in Ghana.
More importantly, this study in the Ghanaian setting also demonstrates non-compliance with the WHO universal salt iodization (USI) program proposed specifically to eliminate iodine deficiency disorders. Approximately, 33.3 % of the pregnant women evaluated were not using iodized salt stressing the need to find innovative ways to improve, as well as sustain, the educational programs meant to increase compliance with the WHO USI program. This would increase the understanding by the general public regarding the IDD and the need to use iodized salt to help eradicate these preventable diseases. In support of this argument, only a total of 2.5 % of participants who were not using iodized salt had UIC above sufficient levels. In contrast, a total of 66.3 % of the participants on iodized salt had UIC above sufficient levels. As it is documented that excess iodine is associated with adverse effects such as hyperthyroidism and thyroiditis [16], this study also demonstrates the need to routinely monitor the salt iodization program so as to ensure a median UIC of 100–200 ?g/L as recommended by the WHO [17] in order to prevent iodine-induced hyperthyroidism and other adverse effects of excess iodine. Participants in the 25–29 year group had the lowest proportion of subjects with less than sufficient UIC as well as the highest proportion of subjects with more than sufficient UIC, suggesting that this age group may be more willing to take regular iodine supplementation in their diet.
To our knowledge this is the first study to use the persulfate method to estimate urine iodine in the Ghanaian population. However, this work has few limitations. First, a larger sample size would have shed more light on the correlation between participant age group and their compliance with the USI program. Second, although adequate amount of iodine (50Â ppm) exist in iodized salt in Ghana, the methods of food processing, and cooking in individual households is likely to have affected the iodine levels in the participants. Third, this study is limited by our inability to obtain verification from independent bodies associated with quality controls of iodine assays. Finally, the iodine content in the local water supply was not determined.