Identifying the malnourished within Peru: regional variation in the performance of a nutrition indicator.

Malnourished children may also have siblings at increased risk of poor health. Early identification of siblings at risk could lead to timely intervention to prevent the development of malnutrition or other potentially life-threatening events. In a nationwide survey conducted in Peru in 1984, stunting in an older sibling (defined as height/age less than or equal to 3.00 SD of the NCHS/CDC reference median) was evaluated as an indicator for stunting in a target sibling (next youngest) sibling) (n = 3284). The prevalence of stunting was much higher in target siblings who had an older sibling with stunting compared to those whose older sibling was not stunted, with prevalence ratios of 8.5 in Lima, 4.7 in urban areas, and 2.5 in rural areas. Screening indices (sensitivity, specificity, and predictive value positive) also showed marked variation across regions. The variation in this indicator's performance across regions demonstrates the importance of evaluating screening tools within the populations where they will be applied. Regional variations in the performance of malnutrition indicators should be anticipated because malnutrition is the result of a complex, multifactorial process.