Correlation between thoracolumbar curvatures and respiratory function in older adults

Figures & data

Table 1 Characteristics of participants

Variables	Mean (standard deviation)
Mean age (years)	66.63 (5.16)
Mean BMI (kg/m^2)	25.04 (3.01)
Gender
Female, n=48 (%)	70.60
Male, n=20 (%)	29.40
Physical activity level (score)	7.45 (0.95)

Abbreviation: BMI, body mass index.

Table 2 Mean and standard deviation of thoracolumbar curvatures angle, respiratory muscle strength, respiratory rate, lung functions parameters and respiratory muscles thickness

Variables	Mean (standard deviation)
Thoracic curvature angle (°)	−46.30 (14.66)
Lumbar curvature angle (°)	14.10 (10.58)
Mean respiratory rate (bpm)	19.62 (3.88)
RMS
Percentage predicted MIP (%)	84.74 (30.96)
Percentage predicted MEP (%)	93.09 (35.66)
Predicted RMS	88.91 (29.66)
Lung function (%)
Predicted FEV1	85.75 (26.11)
Predicted FVC	80.31 (16.27)
FEV1/FVC	85.26 (7.25)
Diaphragm muscle thickness (cm)
End of quiet inspiration	0.29 (0.07)
End of quiet expiration	0.21 (0.05)
End of deep inspiration	0.54 (0.14)
End of deep expiration	0.21 (0.05)
Quiet thickening fraction	1.38
Deep thickening fraction	2.57
Intercostal muscle thickness (cm)
End of quiet inspiration	0.54 (0.11)
End of quiet expiration	0.62 (0.13)
End of deep inspiration	0.52 (0.11)
End of deep expiration	0.65 (0.14)
Quiet thickening fraction	0.87
Deep thickening fraction	0.80

Notes: Thoracic curvature angle (thoracic kyphosis) is reported as negative, reflecting a convex curvature, whilst, lumbar curvature angle (lumbar lordosis) is reported as positive, reflecting a concave curvature.

Abbreviations: MIP, maximal inspiratory pressure; MEP, maximal expiratory pressure; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; RMS, respiratory muscle strength.

Table 3 Correlation between thoracolumbar curvatures and respiratory functions

Respiratory functions	Thoracic curvature		Lumbar curvature
	r/rs	P-value	r/rs	P-value
Respiratory rate	−0.136	0.134	−0.107	0.193
Lung function test
FEV1	−0.232	0.029*	0.057	0.322
FVC	−0.317	0.004*	−0.021	0.433
FEV1/FVC (%)	0.15	0.111	0.053	0.333
MIP (% predicted)	0.129	0.408	−0.244	0.022*
MEP (% predicted)	0.023	0.427	−0.284	0.010*
Diaphragm thickness
DQI	−0.137	0.133	−0.128	0.150
DQE	−0.193	0.057	−0.149	0.112
DDI	−0.163	0.093	−0.222	0.035*
DDE	−0.209	0.043*	−0.051	0.241
Intercostal thickness
IQI	−0.183	0.067	−0.022	0.429
IQE	−0.215	0.039*	−0.013	0.459
IDI	−0.182	0.068	−0.091	0.230
IDE	−0.151	0.110	0.011	0.464

Note:

* Significant level at alpha, P<0.05.

Abbreviations: r, Pearson’s correlation; r_s, Spearman’s rho; DQI, diaphragm thickness during quiet inspiration; DQE, diaphragm thickness during quiet expiration; DDI, diaphragm thickness during deep inspiration; DDE, diaphragm thickness during deep expiration; IQI, intercostal thickness during quiet inspiration; IQE, intercostal thickness during quiet expiration; IDI, intercostal thickness during deep inspiration; IDE, intercostal thickness during deep expiration; MIP, maximal inspiratory pressure; MEP, maximal expiratory pressure; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.