Birth dimensions in Melanesian and Indian Fijians and their relationships with maternal and socio-economic factors

Summary Fifty-nine Melanesian (MF) and 39 Indian (IF) Fijian full-term newborns were studied within 5 days of birth. Dimensions recorded included birthweight, length, crown-rump length, head circumference, upper limb length, bycondylar humeral and femoral diameters and four skinfolds (triceps, subscapular, suprailiac and thigh). Data from previous pregnancies of the presenting newborns' mothers were added to presenting birthweights, giving a total of 160 MF and 84 IF birthweights. In all birthweight and linear dimensions MFs were the bigger. Sex differences were significant in respect only of head circumference and the two bicondylar diameters. Multiple regression analysis showed dimensions in MF newborns to have few significant relationships with the maternal and socio-economic variables of age, parity, stature and years of education, but IFs had many more significant relationships. When covariance correction was made for the significant maternal and socio-economic variables (maternal age and parity) little effect on racial differences was seen. All linear dimensions except length could be subsumed into birthweight. MFs had greater triceps and subscapular skinfold thicknesses than IFs, a difference which was not much changed by covariance correction for significant maternal and socioeconomic variables (maternal stature and years of education). Measurements of shape, expressed as ratios of linear dimensions, showed few racial differences but males had relatively broader limbs. For upper limb shape only, this difference was maintained after covariance correction for significant maternal and socio-economic variables (parity, stature and education). The greater size of MF infants at birth is associated with lower peri- and neonatal death rates. However this advantage is reversed during the remainder of the first year of life. It is suggested that better standards of infant care among IFs are responsible for this change. Zusammenfassung 59 melanesische (MF) und 39 indische (IF) ausgetragene Neugeborene aus Fidschi wurden innerhalb fünf Tagen nach der Geburt untersucht. Die erfaten Dimensionen umschlossen Geburtsgewicht, Länge, Scheitel-Stei-Länge, Kopfumfang, Oberarmlänge, Kondylenbreite von Humerus und Femur und view Hautschichtdicken (am Trizeps, subskapular, suprailiakal und an der Hüfte). Hinzu kamen Körpergewichtsdaten von früheren Schwangerschaften der Mütter der eingeschlossenen Neugeborenen, womit sich eine Gesamtzahl der Geburtsgewichte von 160 MF und