There is a high prevalence among Indigenous Australian young adults of lung function impairment linked to a few different perinatal and early life elements, according to new findings, with some of these elements having potential for intervention and modification.¹

These data resulted from a recent study expanding upon the limited current literature on spirometric deficits prevalence and its associated determinants, though there is evidence of high burden of respiratory disease within Indigenous Australian populations.²

This research was led by Vidya Navaratnam, Department of Respiratory Medicine, Sir Charles Gardiner Hospital, Perth, Western Australia, Australia.

“Without any prospectively collected data from community-based Indigenous adults, we analysed data from a large birth cohort of Indigenous Australians,” Navaratnam and colleagues wrote. “Our aims were to (i) describe spirometry patterns seen in young Indigenous adults, including estimating mean values for FEV1, forced vital capacity (FVC) and (ii) evaluate the association between perinatal and early life exposures with spirometric parameters.”

Background and Findings

The investigators looked at what was known as the Australian Aboriginal Birth Cohort (ABC), made up of singleton babies born to mothers which had identified as Aboriginal or Torres Strait Islanders. The cohort ended up having 686 Indigenous Australians who had been born between 1981 - 1990, residing across the Northern Territory (NT) in more than 40 urban and remote regions.

The research team used the Global Lung Initiative (GLI) reference equations for populations labeled as 'other/mixed'. Their research looked into obstruction of subjects’ airflow, restrictive spirometry, and mixed spirometry, making calculations of several different spirometry parameters such as FEV1% predicted, FVC% predicted, FEV1/FVC ratio, and z-scores.

The investigators looked at perinatal exposures that had been identified using a review of available literature. These exposures included smoking during pregnancy, maternal body mass index (BMI), maternal age, place of birth, hospital admissions for respiratory infections under ages 2 and 5, birthweight, and World Health Organization (WHO) weight-for-age z-scores for the subjects’ early childhood.

The team stratified spirometry through FEV1% predicted considering values from 0 to -2 standard deviations from the group’s population mean. They also assessed participants’ BMI based on guidelines and WHO weight-for-age z-scores through the use of standardized measures.

Linear regression was implemented by the investigators to look at links between perinatal and early life exposures as well as spirometry indices, with the team looking into abnormalities (z-score < -1.64) and FEV1% predicted within the range of 0 to -2SD that is measured in these subjects’ young adulthoods.

Overall, the research team ended up finding that 39.9% (95%CI 31.9, 48.2) were found to have abnormal spirometry. They added that 49.3% (95%CI 40.9, 57.7) were shown to have had an FEV1 under what had been shown to be the population mean.

There were several associated determinants for diminished FEV1 and FVC, such as younger maternal age, pre-school hospitalizations related to respiratory infections, being overweight in early childhood, and remote birth. These were linked in terms of percentage predicted, absolute values, and the subjects’ z-scores.

The notable correlation identified by the investigators between maternal age and both FEV1 and FVC was also shown to be more explicit among females, in addition to a heightened link between subjects’ early-life hospitalizations for respiratory issues and these lung function parameters.

Despite this fact, the team did also note that being born remotely showed a stronger link with diminished FEV1 and FVC in males. They added that subjects who had been born in remote areas were more than 6 times as likely to have an FEV1 under the population mean (odds ratio [OR] 6.30, 95%CI 1.93, 20.59).

“These findings emphasize the need to increase awareness and promote public health interventions that optimize respiratory health in early childhood, especially given the growing evidence that early childhood LRTIs are associated with poorer lung function and premature adult deaths,” they wrote.

References

1. ^{Navaratnam V, Forrester DL, Chang AB, Dharmage SC, Singh GR. Association between perinatal and early life exposures and lung function in Australian Indigenous young adults: The Aboriginal Birth Cohort study. Respirology. 2023. https://doi.org/10.1111/resp.14639.}
2. ^{Bucens IK, Reid A, Sayers SM. Risk factors for reduced lung function in Australian Aboriginal children. J Paediatr Child Health. 2006; 42(7–8): 452–457. https://doi.org/10.1111/j.1440-1754.2006.00896.}