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Growth-faltering rates in California, Guatemala, and Tamil Nadu: Implications for growth-monitoring programmes

Reynaldo Martorell and Meera Shekar

Results

The median weights for the Berkeley, Guatemala, and Tamil Nadu children are plotted relative to the WHO/NCHS reference curves (ninety-fifth, fiftieth, and fifth percentiles) in figure 1 (see Figure. 1. Median weights for boys in three populations compared with WHO/NCHS reference curves) and figure 2 (see Figure. 2. Median weights for girls in three populations compared with WHO/NCHS reference curves). The medians for Berkeley were consistently above the reference median, while those for both the developing country samples were below the fifth percentile. Also, the medians for Tamil Nadu were consistently lower than those for Guatemala.

The differences in median weight for boys at 24 and 12 months were 2.8 kg in Berkeley and 1.7 in both Guatemala and Tamil Nadu, compared with 2.4 kg in the WHO/NCHS reference population. In girls, the weight gains were 2.6, 1.9, and 1.5 kg respectively in Berkeley, Guatemala, and Tamil Nadu, compared with 2.4 kg in the reference sample. Compared with incremental growth charts that use Fels Research Institute data [18], the weight growth velocities in boys and girls exceeded the fiftieth percentile in the Berkeley sample but were around the tenth percentile for the other two samples.

Length values were not available for Tamil Nadu. The median lengths for Berkeley exceeded the reference median, particularly after 12 months of age, but the medians for Guatemala were much lower than the fifth percentile.

The distribution of three-month weight increments is given in table 1. Here, the unit of analysis is child-period, as each subject may contribute as many as four values to the total. Analyses restricted to only individuals with complete data for all periods give results similar to those shown in the table. As expected, the weight increments were larger in Berkeley than in either Tamil Nadu or Guatemala. The degree of faltering was similar in boys and girls in all three populations.

TABLE 1. Distribution of three-month weight increments measured between 12 and 24 months of age

Periods are 12-15, 15-1A, 18-21, and 21-24 months.

Chi-square tests with three degrees of freedom were applied to the following: Berkeley boys vs. girls (5.66, NS), Guatemala boys vs. girls (4.93, NS), Tamil Nadu boys vs. girls (1.35, NS); Berkeley vs. Guatemala (120.76, p<.001), Berkeley vs. Tamil Nadu (231.81, p< .0001), and Guatemala vs. Tamil Nadu (149.13, p<.001)

The definition of faltering in the second year of life as a weight gain of less than 300 g over a three-month period is widely used. The percentages of all three-month increments that indicate faltering according to this definition are shown in figure 3 (see Figure. 3. Percentages of all three-month weight increments of less than 300 g (based on data from table 1)). Some 17.1% of the increments in boys and 10.7% in girls in Berkeley were classified as faltering. The rates were two to three times as great in Guatemala and Tamil Nadu.

In table 2 the children are classified according to the number of episodes of growth faltering they experienced within the age ranges studied (12-24 months in Berkeley and Guatemala, with a possible range of 0-4 episodes; 1221 months in Tamil Nadu, with a possible range of 0-3 episodes), using both definitions of faltering: a weight gain of 0 g or less (i.e., no change or loss of weight) over three months, and one of less than 300 g. The analysis is restricted to individuals with complete information for all possible child-periods. The sexes are combined because of the general similarity in the distribution, particularly in Guatemala and Tamil Nadu. Although faltering was considerably more frequent in Guatemala and Tamil Nadu, it did occur in many Berkeley children, a few of whom had repeated episodes of faltering.

TABLE 2. Children classified by number of episodes of growth faltering, 12-24 months of age (Berkeley, Guatemala) or 12-21 months (Tamil Nadu) according to two criteria—growth <=0 g and growth < 300 g over three months

For Berkeley and Guatemala, based on weight measurements taken at ages 12,15,18, 21, and 24 months. For Tamil Nadu, the data were abstracted from the records in such a way that three-month increments can be determined only for ages 12-15, 15-18, and 18-21 months The sexes are combined in all the groups.

The percentage of children who faltered (<= 0 g and < 300 g) in at least one period from 12 to 24 months is shown in figure 4 (see Figure. 4. Percentages of children faltering in growth in at least one three- month period between the ages of 12 and 24 months (based on data from table 2; for Tamil Nadu, the values based on three periods are projected to four).). The values for Tamil Nadu are adjusted for the fact that faltering was observed over only three periods; using the methods described earlier, the values shown project the rate of faltering to four periods of observation.

With a weight gain of 0 g or below as the criterion for faltering, 17.6% of the children in Berkeley faltered at least once between 12 and 24 months of Figure. 4. Percentages of children faltering in growth in at least one three-month period between the ages of 12 and 24 months (based on data from table 2; for Tamil Nadu, the values based on three periods are projected to four) age, compared with 45.4% and 42.0% in Guatemala and Tamil Nadu respectively. In other words, faltering in at least one period was about 2.5 times as likely to occur in Guatemala and Tamil Nadu as in Berkeley. When a gain of less than 300 g is used as the criterion, the percentage of children in Berkeley who faltered at least once rises to 36.8%, compared with 82.4% in Guatemala and 73.6% in Tamil Nadu. Using the second definition, the rate of faltering in at least one period was twice as great in Guatemala and Tamil Nadu as in Berkeley.

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