Mid arem circumference (MAC) has been shown to be a simple, sensitive and cost effective measurement for community asessement of early childhood malnutrition. It is well established between the age group of 12 months to 60 months(1-4). MAC is age independent and has a high correlation with weight for age(2,5). It has many practical advantages over the standard anthropometry weight for age (W A), especially at the community level(l,5,6). The utility of MAC as an index of protein-energy malnutrition (PEM), even at the age of 6 months to 12 months has now been shown by various western studies(3,7).

Growth faltering in an infant starts between the ages of 3 months to 12 months(5,8,9). Detection and early intervention at this crucial age has been shown to produce dramatic results in correcting the nutritional deficiencies(3). MAC as a diagnostic tool of PEM between ages of 6-12 months in the field settings has not been well explored. In the present study, MAC was compared with W A to show its validity as an index of PEM and to find suitable MAC cut points for detection of PEM between the ages of 6-12 months.

Subjects and Methods

This study was conducted between Au- gust 1995 to January 1996. All data were collected by the author PB and cross-checked by the author JNS in the Out Patient Department and Immunization Clinic of the Department of Pediatrics, Guwahati Medical College and Hospital.

The study population comprised of 350 children aged between 6-12 months. Only those children with birth certificate were selected. Babies with illness (acute or chronic) were not included. Only babies who were brought for monthly check up and immunization were included. Weight was taken by a Salter's balance (Model 235PBW) in kg corrected to the nearest 500 gm. Weight was. taken with minimum do thing and the callibration of the weighing scale was checked daily with a known weight. The MAC measurements were taken by a fibreglass tape, on the left upper arm at the point midway between the tip of the acromian process of scapula and tip of olecranon process of ulna, with an accuracy of up to 1 mm(10).

Different cut-off points of MAC and W A were compared with each other to find suitable MAC cut-off points with maximum sensitivity, specificity, positive and negative predictive values. The prevalence rates of PEM for different MAC cut-off points were also compared to find auf the degree of correlation between MAC and WA.

Results

Table I displays the comparison between two levels of W A and six MAC cut-off points in 350 children. The MAC cut point of 12.5 cm on comparing with W A <60% revealed a high sensitivity of 100%, specificity of 98%, positive predictive value of 77%and negative predictive value of 100%. Similarly, the MAC cut point 13.5 cm agreed best with W A <80% of median as it yielded a sensitivity of 85%, specificity of 100%, positive predictive value of 100% and negative predictive value of 95.9%.

 

Table II shows comparison between the prevalence rates of PEM with different cut points of MAC and W A. The number of malnourished children detected by MAC cut point of 12.5 cm was 27 (7.7%) and it

closely resembled with that of 21 (6%) detected by W A <60% of median. MAC cut point of 13.5 cm detected 68 (19.4%) mal- nourished children which is comparable to 80 infants (22.9%) detected by WA<80% of median. Lower MAC cut-offs like 12 cm or 11 cm showed great disparity in prevalence rates and yielded lower sensitivity values.

Discussion

Nutritional screening is an important part of a community health care system and the major interest lies in detecting the mild and moderate grades .of PEM(2,11) as nutritional intervention in such cases can be enforced by the community health workers. The present study found the MAC cut-point of 13.5 cm to have high sensitivity (85%) and specificity (100%) rates in detecting mild and moderate grades of PEM. The prevalence rate (19.4%) of this cut-point was similar to that of WA<80% of median (22.9%). Shakir in his report of 777 Baghdad children aged 3-72 months(1), used MAC cut off 14 cm to correspond W A 80% and he observed that it overdiagnosed many normal children as malnourished between the age of 3-12 months. Pust et al. found the MAC cut-off of 12.5 cm to correlate well with WA<80% of median(11). In the present study MAC cut of point of 12.5 cm produced low prevalence and sensitivity rates on comparing with W A <80% of median.

Severe PEM in the field settings needs to be screened and referred early to a dIstrict hospital for better management and MAC cut-point of 12.5 cm produced a sensitivity rate of 100% and specificity rate of 98% in detecting these cases. It also showed good correlation with the standard anthropomentry W A <60% and yielded the prevalence rates of 7.7% and 6%, respectively. These observations are in concordance with others(3,6). Hence MAC is an ideal tool for detection of PEM at the age of 6-12 months; and can be used for screening of PEM, specially in the community level. However, further studies are required in the Indian context in a larger sample for proper evaluation.

Acknowledgement

We are grateful to Professor A.K. Barooah, Principal cum Chief Superintendent of Gauhati Medical College and Hospital for allowing us to carry out the present study in the hospital.