Evaluation of iodine levels in the Riverina population

To assess the iodine status in a random group of adults in a rural region.

A cross-sectional study; urinary iodine concentrations (UIC) were correlated with results of a questionnaire that collected demographic information.

Primary care.

A total of 173 adults from the Riverina region provided a morning midstream urine sample and completed a questionnaire. There were no exclusion criteria.

Iodine status was based upon mean UIC (MUIC) values and categorised according to World Health Organisation criterion. Subgroups were classified according to sex, age, town, salt usage, vitamin/supplement usage, pregnant or breast-feeding status and diet.

The MUIC for the study population was 79 microg L(-1); 29% were iodine-replete, 52% had mild deficiency and 18.5% were moderately to severely deficient. Use of iodised salt produced a non-clinically significant increase in MUIC of 81 microg L(-1)compared with 71 microg L(-1)(P = 0.1907). Daily vitamin supplementation led to iodine sufficiency with a MUIC of 111 microg L(-1)(P = 0.0011). Participants aged 50-59 years had a significantly lower MUIC than participants aged 18-39 years (67 versus 89 microg L(-1), respectively, P = 0.0106). Further, the MUIC decreased with age from 18 to 59 years (P = 0.0208).

A mild iodine deficiency was found in this sample of the Riverina population, consistent with other Australian studies. Salt iodisation might not be an effective strategy to correct iodine deficiencies within Australia.