Indian Pediatrics 1999; 36:257-262

A. K. Bhalla

 From the Advanced Pediatric Center, Post Graduate Institute of Medical Education and Research, Chandigarh,1600l2,lndia.

 Reprint requests: Dr. A.K. Bhalla, Associate Professor, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.

 Manuscript received: April 6, 1998; Initial review completed: June 3, 1998;
Revision accepted: September 22, 1998.

 

Objective: To study distance and velocity growth pattern of mid-upper-arm-circumference in Punjabi infants. Design: Longitudinal, monthly follow up. Setting: Growth clinic and homes of subjects. Sample: One hundred and fifty four (Male 86, Female 68) Punjabi infants weighing more than 2.5 kg at birth with gestation over 37 weeks. Methods: Every subject was measured for mid­upper-arm circumference between 1 to 12 months of age at one monthly intervals by the same investigator with a time tolerance of :t3 days on the day of measureme1lt. Results: Mid upper arm circumference .showed rapid increase between 1 to 6 months whereafter, gain became slower during second half of infancy. It had grown by 34.9% in male and 40.2% in female infants between 1 to 12 months. Sex differences favoring male infants were statistically significant between 1 to 4 months. Monthly growth rates for arm-circumference depicted vascillatory pattern. Conclusion: The values presented for arm circumference may be used as reference base to monitor growth of children during infancy.

 Key words: Arm: Circumference, Growth.

 

THE role of upper limb anthropometry in the assessment of nutritional status of human subjects has been well recognised(1-5) and mid-upper arm circumference is widely used as a measure of thinness(6) to detect undernutrition and high risk of death in children(7).

Studies involving growth of arm-circum­ference conducted in different parts of the world(8) reveal that data have mainly been reported for age-period extending beyond the first year. The monthly figures for arm­circumference provided by Wolanski for healthy Polish children(9) given in a WHO monograph( 1) have been used world wide for making age and sex appropriate comparisons.

The data on mid-upper arm-circumference of American children representing combined sexes from 6 to 60 months of age have been recommended by WHO(5) as reference base to predict mortality and assess nurtitional status of children. Additional sets of data on arm-circumference of American infants to assess nutritional and growth status of older infants were reported by other workers(10). These data however, did not include values for the first six months of life.

Auxological studies involving mid-upper­arm circumference conducted on Indian infants are few in number. Growth of arm­circumference along with other body dimensions was longitudinally studied(11) amongst pre-school children of. different socio­economic classes. The authors pooled the data for children of the two sexes and treated it as if these were cross-sectional in nature. They presented. distance mean values at 3 monthly age intervals during the first year of life. No attempt was made to calculate growth velocity, i.e., rate of growth. Gupta et at:(12), studied the arm circumference in children residing in urban slums of Kanpur. These authors pooled the data of children at 3 years intervals, hence the data cannot be used to make age appropriate growth comparisons. Mathur et al.(13) studied the arm-circumfer­ence of breastfed babies at monthly age levels only up to six months of life and data for second half of infancy are lacking. A mixed-longitudinal study conducted by Agarwal and Agarwal(14) provided 3 monthly distance means and half yearly velocity figures for arm-circumference during the first year of life.

 An inspection of the anthropometric information available on the growth of mid­upper-arm-circumference reveals, that pure­longitudinal data, particularly, on monthly growth rates of infants of Indian origin are lacking. Hence, in the present study an attempt was made to generate age. and sex appropriate sets of data to monitor monthly distance. and velocity growth attainments of infants of Punjabi origin.

Subjects and Methods

One hundred and fifty four infants (male: 86 and female:. 68) born to Punjabi speaking parents living in the Union Territory of Chandigarh, India, and followed at monthly age intervals between 1 to 12 months age comprised the material for this longitudinal study. Each subject weighed more than 2.5 kg at birth and had gestation over 37 weeks. Except for one, every infant was breastfed from birth to six months of age. However, semi­solid diet in majority of infants (89.6%) was introduced after 5 months of age. Other salient characteristics of the sample and method­ology followed are given elsewhere(15).

The left mid-upper-arm circumference of every subject sitting in the lap of his/her mother or care taker was measured at mid point (marked with skin marking pencil) lying between tip of the acromion process of scapula and olecranon process of ulna following standardized technique(16). The measurement at the marked level was made with a steel tape over infant's arm hanging relaxed and away from subject's side. The measurement was recorded in centimeters upto the accuracy of nearest one millimeter. Every infant was measured twice for the circumference of arm and an average of the two measurements. was treated as final value.

The enrolment of babies in this longitudi­nal study was made at birth yet the measure­ment of arm circumference in each. subject was started at one month of age. All measure­ments were taken by the author (AKB) in the Growth Clinic of the Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh at one monthly intervals with time tolerance of ± 3 days on the day of measurement from 1 to 12 months of age. The subjects who did not attend clinic on the appointed dates were measured in their homes. The level of measuring error in the present study varied between 0-2 mm which is within the values. for inter, and intra-rator errors provided by earlier workers(17).

Conventional statistics were used to com­pute mean, SD and ± 1.96 SD for arm-cir­cumference amongst infants of the two sexes at each monthly age level extending between I to 12months. Rate of growth was calculated for every individual infant by taking differ­ence between the two consecutive values. Monthly increments calculated for every infant were used to calculate mean rate of growth and its standard deviation. Magnitude of sex -differences for both distance and velocity values were quantified by applying Student's unpaired-t -test.

Results

The mean (X), Standard Deviation (SD) and X ±1.96 SD values computed for male and female infants at monthly age levels ex­tending between 1 to 12 months are shown in Table I. The mean mid-upper-arm-circumference (MUAC) showed a rapid increase from 1 to 6 months of age, where after, average monthly gain became slower during the second half of infancy. It had grown by 34.9% in male and 40.2% in female infants between 1 to 12 months. The mean (± SD) values for MUAC measured 10.12±0.67 cm and 13.66±1.07 cm at 1 and 12 months, respectively in male infants. The corresponding figures for female infants were 9.87±0.78 cm and 13.84±1.28 cm.

TABLE I

Mean, Standard Deviation and ±1.96 SD for Ann Circumference (cm) in Punjabi infants

Age (mo)	n	Male		X ± 1.96 SD	n	Female		X±1.96 SD	Sex difference (t - value)
		Mean	SD			Mean	SD
1	86	10.12	0.67	8.81-11.43	68	9.87	0.78	8.34-11.40	2.17*
2	86	11.12	0.83	9.49-12.75	68	10.85	0.86	9.17-12.53	1.99*
3	86	11.81	0.84	10.16-13.46	68	11.49	0.98	9.57-13.41	2.4*
4	86	12.39	0.91	10.61-14.17	68	12.00	0.88	10.28-13.72	2.60**
5	86	12.72	0.91	10.94-14.50	68	12.47	0.87	10.77-14.17	1.75
6	86	13.01	1.08	10.89-15.13	68	12.75	0.96	10.87-14.63	1.73
7	86	13.13	1.16	10.86-15.40	68	12.95	1.04	10.91-14.99	0.97
8	86	13.27	1.20	10.92-15.62	68	13.12	1.14	10.89-15.35	0.79
9	86	13.28	1.12	11.09-15.47	68	13.22	1.08	11.10-15.34	0.33
10	86	13.39	1.04	11.35-15.43	68	13.30	1.08	11.18-15.42	0.53
11	86	13.49	1.08	11.37-15.61	68	13.47	1.05	11.41-15.53	0.12
12	86	13.66	1.07	11.56-15.76	68	13.84	1.28	11.33-16.35	0.68

** p≤0.01; *p≤0.05; DF=152

Male infants in general, possessed higher mean values for upper-mid-arm circumfer­ence at all monthly ages than their female counterparts between 1 to 11 months. The magnitude of sex differences favoring male infants was statistically significant (p ≤ 0.05) only between 1-4 months. However, female infants showed marginally higher average than the males only at 12 months of age (Table /).

The monthly rates of growth (means, standard deviations) calculated amongst Punjabi infants are shown in Table II and Figure l. Mean±SD growth rates calculated for arm circumference between 1 to 4, 4 to 6 and 6 to 12 months age intervals are also presented. Of all the age intervals considered, the magnitude of sex differences was found to be statistically significant (p≤0.05) only between 6-12 months of age, where females had shown higher growth rates than their male counter­parts (Table Il).

TABLE II

 Mean (± SD) Increments for Arm Circumference (cm) in Punjabi infants for Various Age Intervals

Age interval (mo)	n	Male			Female		Sex differences (t-value)
		Mean	SD	n	mean	SD
1-2	86	1.00	0.55	68	0.98	0.52	0.31
2-3	86	0.69	0.66	68	0.68	0.53	0.07
3-4	86	0.57	0.52	68	0.51	0.37	0.14
4-5	86	0.34	0.53	68	0.46	0.36	0.27
5-6	86	0.29	0.55	68	0.26	0.48	0.07
6-7	86	0.11	0.42	68	0.23	0.37	0.29
7-8	86	0.14	0.53	68	0.17	0.47	0.05
8-9	86	0.01	0.58	68	0.10	0.49	0.12
9-10	86	0.11	0.42	68	0.08	0.49	0.07
10-11	86	0.11	0.36	68	0.18	0.39	0.19
11-12	86	0.16	0.35	68	0.31	0.67	0.29
1-4	86	2.32	1.00	68	2.14	0.65	1.31
4-6	86	0.56	0.90	68	0.72	0.58	1.25
6-12	86	0.65	0.85	68	0.98	0.79	2.39*

*p ≤0.05; * DF = 152

 

Fig. 1. Growth velocity curves for mid-upper arm circumference in Punjabi infants

Discussion

Mid upper-arm circumference amongst the infants studied showed rapid increase between one and six months of age followed by a slower gain upto 12 months of age. The initial rapid increases in the circumference of arm and gradual slowing down of its course during second half of infancy conforms to the general somatic growth pattern of skeletal system(l8) noticed during infancy. Male in­fants in general possessed higher mean values than their female counterparts. However, the magnitude of sex differences was statistically significant (p≤ 0.05) only till the age of 4 months (Table l). 

The values for arm-circumference of male and female study infants from 1 to 12 months of age were lower than the infants of Polish origin(1,9) as well as their American(10) counterparts studied between 7 to 13 months. The data for American infants during the first six months of life do not exist. These differ­ences may be racial in origin. The higher val­ues reported amongst breast-fed infants from Gorakhpur(13) may also be explained on ethnic grounds since infants representing both the groups were breast-fed during first six months of life.

As indicated by the mean values arm circumference between 7 to 12 months increased approximately by 4% in male and 6.9% in female infants. In comparison to this, the arm circumference increased by I 1.4% in Ameri­can boys and 3% in girls between 7 to 13 months of age(10). These data indicate that strictly speaking arm does not increase substantially during second half of infancy as proposed by other researchers(19-21) and can be deemed to be age independent variable from the age of six month onwards.

A regular deceleration in the rate of growth of mid-upper-arm circumference obtained in terms of monthly increments is noticed from 1.5 to 8.5 months in males and 1 to 9.5 months in female infants and thereafter, a slight increase in the rate of growth is seen (Fig. 1). However, a high degree of variability, (SD) around the mean rates (Table /I) makes it difficult to understand the dynamics of velo­city growth pattern of arm circumference. Generally, in longitudinal studies non-adher­ence to time-tolerance limit and failure to maintain constant sample size throughout the study span are considered as the two main rea­sons for the existence of substantial degree of variability. In the present study, both of the contributing factors were controlled therefore, the larger variability encountered around mean increments cannot be explained on the basis of methodological problems.

In view of the non-availability of appro­priate sets of monthly incremental data during the first year of life on the growth of arm cir­cumference in Indian subjects, comparison of this parameter of infant growth could not be attempted. However, keeping in mind general recommendations to breast feed the infants exclusively from birth to 4-6 months and introduce suitable and adequate food supple­ments at subsequent ages during which growth rate is generally reduced, the velocity data provided for larger age intervals (i.e., 1-4, 4-6, and 6-12 months) may be of help to compare and understand the growth dynamics of arm circumference of Indian infants growing under a variety of nutritional, economic and socio-cultural settings.

The values, presented for arm-circumfer­ence may be used for comparative purpose to monitor growth and nutritional attainments of the infants between 1 to 12 months of age. The child with value falling outside the upper and lower limits of the confidence interval (X ± 1.96 SD) has less than 5% of chances of being normal.

Acknowledgements

Author is grateful to Dr. B.N.S. Walia, Emeritus Professor, Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh for his guidance, pertinent suggestions and scholarly evalua­tion of the contents of this research manuscript.