Table 4. Total Lung Capacity (TLC) values for participants by Indigenous status and stratified by sex and age (≤ 35 & > 35 years).

	Indigenous Australian (n = 129)	Australian Caucasians (n = 197)	p-value
Total sample
TLC (L)	4.06 (3.87, 4.25)	5.09 (4.93, 5.24)	<0.01*
TLC (%)	73.31 (70.62, 76)	89.94 (88.2, 91.69)	<0.01*
TLC LLN	4.51 (4.35, 4.67)	4.62 (4.48, 4.76)	0.35
TLC < LLN	85 (66%)	41 (21%)	<0.01*
Females
≤ 35 years	n = 14 (18%)	n = 11 (9%)
TLC (L)	4.09 (3.55, 4.63)	4.81 (4.31, 5.31)	0.048*
TLC (%)	81.21 (72.5, 89.92)	90.09 (83.32, 96.87)	0.11
TLC LLN	4.04 (3.76, 4.31)	4.33 (4.08, 4.58)	0.11
TLC < LLN	6 (43%)	2 (18%)	0.19
> 35 years	n = 66 (82%)	n = 124 (91%)
TLC (L)	3.59 (3.38, 3.81)	4.57 (4.44, 4.7)	<0.01*
TLC (%)	73.14 (69.18, 77.1)	91.13 (88.79, 93.46)	<0.01*
TLC LLN	3.95 (3.8, 4.09)	4.01 (3.94, 4.09)	0.36
TLC < LLN	43 (65%)	18 (15%)	<0.01*
Males
≤ 35 years	n = 14 (29%)	n = 11 (18%)
TLC (L)	4.97 (4.37, 5.57)	6.44 (5.78, 7.1)	<0.01*
TLC (%)	71.36 (63.43, 79.28)	91.45 (84, 98.91)	<0.01*
TLC LLN	5.78 (5.48, 6.07)	5.88 (5.53, 6.23)	0.62
TLC < LLN	11 (79%)	2 (18%)	<0.01*
> 35 years	n = 35 (71%)	n = 51 (82%)
TLC (L)	4.57 (4.21, 4.93)	6.11 (5.82, 6.4)	<0.01*
TLC (%)	71.26 (66.28, 76.23)	86.71 (83.63, 89.78)	<0.01*
TLC LLN	5.27 (5.06, 5.48)	5.87 (5.66, 6.08)	<0.01*
TLC < LLN	25 (71%)	19 (37%)	<0.01*

Abbreviations: TLC, Total lung capacity; LLN, Lower limit of normal.

Data were expressed as mean (95% confidence interval) and number (%).

TLC (%, LLN) data were derived from the NHANES (National Health and Nutrition Examination Survey) norms.

Differences between groups tested with two-tailed students T-test for continuous parameters and proportions z-test for categorical parameters.

*Denote statistically significant differences (p<0.05).