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[Growth of exclusively breast-fed Chilean infants in relation to new 1994 WHO Reference Charts]
E Atalah Samur1, C Castillo Lancelloti
1Departamento de Nutrición, Facultad de Medicina, Universidad de Chile, Unidad de Nutrición, Ministerio de Salud.
Insights
Chilean infants
Area of Science:
- Pediatrics
- Nutrition Science
- Public Health
Background:
- Current World Health Organization (WHO) guidelines recommend specific infant feeding practices.
- Growth monitoring is crucial for assessing infant health and nutritional status.
- Existing WHO and NCHS/WHO growth charts are used for comparison.
Purpose of the Study:
- To evaluate the growth patterns of Chilean infants from medium-to-low socioeconomic status.
- To compare infant growth against the new WHO reference charts and NCHS/WHO growth standards.
- To assess the implications of different growth charts on nutritional status classification.
Main Methods:
- Analysis of a nationwide infant feeding survey conducted in Chile in 1993.
- Selection of 1879 infants (939 males, 940 females) aged 1-12 months with exclusive breastfeeding.
- Calculation of weight-for-age z-scores (WAZ) and height-for-age z-scores (HAZ) using NCHS/WHO and new WHO growth charts.
Main Results:
- Observed WAZ was initially below the new WHO reference but increased over time.
- HAZ results were consistently lower than the new WHO reference, though improved in the second semester.
- The growth pattern more closely resembled the NCHS/WHO chart than the new WHO chart.
- The new WHO chart classified a significantly higher proportion of infants as subnormally nourished during the first semester.
Conclusions:
- The new WHO growth chart may overestimate subnormal nutritional status in Chilean infants compared to NCHS/WHO standards.
- Discrepancies between growth charts could influence early introduction of complementary foods.
- The homogeneity of the population used for the new WHO reference chart may limit its applicability in diverse developing countries.
Abstract:
The aim of this study was to evaluate the growth of Chilean infants from medium-to-low socioeconomic status fed according to the current WHO guidelines. Growth pattern was compared to a recent reference chart published by WHO for infants, and the NCHS/WHO growth standards. The source of information was a nation-wide infant feeding survey conducted in 1993. From this database, infants aged 1-12 month +/- 5 days, with exclusive breast feeding until the fourth or sixth month were selected (939 males, 940 females). The weight-for-age z-score (WAZ), and the height-for-age z-score (HAZ) were calculated using both the NCHS/ WHO and the new WHO reference growth charts. At each month of age, WHZ and HAZ results were grouped in the following categories: < = -2.0; -1.9 to -1.0; 0 +/- 0.9; 1.0 to 1.9; and > = 2.0. Observed WAZ at the first month of age was below the new WHO reference chart (0.32 z-score), increasing up to 1.29 z-score at the tenth month. The HAZ results were lower the WHO reference chart throughout the period studied, although a trend to improved values was noted during the second semester (F = 6.01 p < 0.001). Growth pattern of the studied group was more similar to the NCHS/WHO chart than the new chart proposed by WHO. As a consequence, the new WHO reference chart identifies a higher proportion of the infants as having a subnormal nutritional status during the first semester of life, compared to those classified in this category by the NCHS/WHO standards (p < 0.001). This can be a factor for the introduction of complementary foods early in life. The relative homogeneity of the population used as source of the WHO reference chart may limit it use in developing countries.