Ethnic variation in premmies

Data on the genetic diversity of Australian babies might allow for better neonatal outcomes.

AS IN the rest of the world, patterns of immigration to Australia have changed dramatically over the past 20–30 years. 

We have moved from predominantly Caucasian migrants from the UK and Europe, to increasing numbers of people from Asia, especially China, and an increase in Polynesian and Maori migrants. 

With this has come a change in our demography that filters down into all facets of healthcare access and utilisation. 

One example of these changes was recently published by Ruan and colleagues at the Neonatal Intensive Care Units (NICUs) Group from an audit of admissions to all 10 neonatal units in NSW and the ACT. More than 10,000 infants born between 1995 and 2006 at  less than 32 weeks’ gestation were included in the study. 

It showed that during the 12-year study period, 84% of births were of Caucasian background, 9% were Asian, 4.3% were to Indigenous parents, 1.2% were of Pacific and Maori (PAM) background, and 1.5% were of miscellaneous other ethnic backgrounds.

The demographics reflected the broader Australian population. Of interest was that maternal ethnicity did not influence neonatal mortality, but it did influence other outcomes, including perinatal asphyxia, intra-ventricular haemorrhage and retinopathy of prematurity. 

Conception was assisted with reprod­uctive technology in 10% of Caucasian women, 8.7% of Asian women, 0.5% of Indigenous women, and none of the PAM women. 

Indigenous mothers were younger and Asian mothers were older than Caucasian mothers. This most likely reflects the socioeconomic demographics of the women. 

There was no significant difference in gestational age between any of the ethnic groups, but birth weight was higher in the Caucasian infants. 

Indigenous mothers had significantly higher rates of illicit drug use, with an odds ratio (OR) of 7.17 compared to Caucasian mothers (who were the reference group), Asian mothers (OR 0.29) and PAM mothers (OR 0.38). 

This finding is worrying because of the long-term learning and developmental issues associated with drug use that are not reflected in the neonatal data. 

The data on developmental outcomes of these children was not reported in this study, but would be of interest. By way of comparison, the typical rate of neuro-developmental abnormalities identified in extremely low birth weight infants (<1000 g) at age five years is of the order of 20–25% in the NSW and ACT NICUs cohort from the early to mid-1990s. 

This figure significantly underestimates the learning difficulties and special educational needs of these infants, which will not come to light until the school years.
 The data in this article reinforces the implications – or in financial terms, the true costs – of caring for infants born extremely prematurely. 

Balancing this are the favourable outcomes that are routinely achieved for many extremely preterm infants in neonatal intensive care units. Yet it is hard not to wonder what might be achieved if more money were to be invested in targeted preventive health campaigns for adolescent girls and young women most at risk of preterm delivery. 

Clinical Professor Dominic Fitzgerald MBBS, PhD, FRACP

Paediatric respiratory and sleep physician at The Children’s Hospital at Westmead, NSW.

Ruan S et al. The associations between ethnicity and outcomes of infants in neonatal intensive care units. Arch Dis Child: doi 10.1136/adc.2011.213702