Measures of the public health significance of micronutrient deficiencies
Where clinical micronutrient deficiencies are detected, they should be urgently treated on an individual basis. Individual cases of clinical micronutrient deficiencies are also usually indicative of an underlying problem of micronutrient deficiency at the population level. Measurement and classification of micronutrient deficiencies at the population level is important for planning and monitoring interventions.
Biochemical tests have the advantage of providing objective measures of micronutrient status. However, the collection of biological samples for testing often presents logistical, staff training, cold chain and sometimes acceptability challenges. Biochemical measurements are also not always as clearly useful, i.e. as sensitive and specific, as might be imagined. There may also be variations according to the time of day the sample is collected and according to the season of the year, as with acute malnutrition. Good quality control is essential and should always be considered when selecting a laboratory for sample testing.
When assessing micronutrient status the possibility of excessive intakes as well as deficiency should be kept in mind. This is of particular concern when multiple, highly fortified products or supplements are used to deliver micronutrients to the affected population.
The table below shows classifications of the public health significance of selected micronutrient deficiencies using different indicators.