Spirometric reference values for Malagasy adults aged 18–73 years

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FIGURE 1
Flow diagram of subjects included and excluded, drawn using the CONSORT (Consolidated Standards of Reporting Trials) template.
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FIGURE 2
Mean forced expiratory volume in 1 s (FEV₁) and mean forced vital capacity (FVC) versus a–d) age and e–h) height for male and female Malagasy coast and highland dwellers.
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FIGURE 3
Z-scores for a) forced expiratory volume in 1 s (FEV₁), b) forced vital capacity (FVC) and c) FEV₁/FVC ratio between observed Malagasy values and predicted values using the third National Health and Nutrition Examination Survey (NHANES III) [2] and Global Lung Function Initiative (GLI) 2012 [4] predictions for males. Z-scores were calculated as (observed-predicted)/sd_pred, where sd_pred is the standard deviation of the predicted value.
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FIGURE 4
Z-scores for a) forced expiratory volume in 1 s (FEV₁), b) forced vital capacity (FVC) and c) FEV₁/FVC ratio between observed Malagasy values and predicted values using the third National Health and Nutrition Examination Survey (NHANES III) [2] and Global Lung Function Initiative (GLI) 2012 [4] predictions for females. Z-scores were calculated as (observed-predicted)/sd_pred, where sd_pred is the standard deviation of the predicted value.

TABLE 1 Demographic data for Malagasy subjects

TABLE 2 Prediction equations for adult Malagasy males and females aged 18–73 years

Lower limit of normal (5th percentile) is estimated as predicted-(1.645×sd_residuals). sd_residuals: standard deviation of the difference between measured and predicted values; FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; H: height in metres; A: age in years.

TABLE 3 Differences between individual Malagasy measured values and predictions for FEV₁, FVC and FEV₁/FVC

Parameter	Study	Group	Males		Females
Parameter	Study	Group	Mean of individual subject differences^# %	Absolute difference	Mean of individual subject differences^# %	Absolute difference
FEV₁ L	Quanjer [3]	ECSC	-10.80	0.11	-6.22	0.06
	Hankinson [2]	Caucasian	-13.95	0.14	-12.98	0.13
		Mexican-American	-15.31	0.15	-13.09	0.13
		African-American	2.77	0.03	4.86	0.05
	Quanjer [4]	Caucasian^¶	-14.39	0.14	-12.42	0.12
		Black⁺	2.41	0.02	3.08	0.03
		North East Asian^§	-10.45	0.10	-10.75	0.11
		South East Asian^ƒ	-4.79	0.05	0.37	0.00
		Other^##	-6.58	0.06	-4.73	0.05
	This study	Malagasy	0.71	0.00	0.50	0.00
FVC L	Quanjer [3]	ECSC	-14.07	0.14	-6.84	0.07
	Hankinson [2]	Caucasian	-22.54	0.23	-15.92	0.16
		Mexican-American	-21.96	0.22	-16.86	0.17
		African-American	-1.31	0.01	2.14	0.02
	Quanjer [4]	Caucasian^¶	-19.90	0.20	-16.23	0.16
		Black⁺	-1.32	0.01	0.51	0.05
		North East Asian^§	-15.14	0.15	-13.22	0.13
		South East Asian^ƒ	-6.58	0.06	0.12	0.00
		Other^##	-10.40	0.10	-6.94	0.07
	This study	Malagasy	0.53	0.00	0.53	0.01
FEV₁/FVC %	Quanjer [3]	ECSC	-9.20	0.09	-9.35	0.09
	Hankinson [2]	Caucasian	7.18	0.07	4.49	0.04
		Mexican-American	-9.45	0.09	-9.67	0.09
		African-American	7.44	0.07	7.80	0.08
	Quanjer [4]	Caucasian^¶	4.64	0.05	3.10	0.03
		Black⁺	3.88	0.04	2.56	0.03
		North East Asian^§	4.11	0.04	2.24	0.02
		South East Asian^ƒ	1.90	0.02	-0.29	0.00
		Other^##	3.62	0.04	2.06	0.02
	This study	Malagasy	-0.34	0.0034	0.05	0.00

FEV₁: forced expiratory volume in 1 s; FVC: forced vital capacity; ECSC: European Community for Steel and Coal. ^#: observed-predicted; ^¶: people from Europe, Israel, Australia, USA, Canada, Brazil, Chile, Mexico, Uruguay, Venezuela, Algeria and Tunisia, and Mexican-Americans; ⁺: equivalent to African-American, with data exclusively from the USA population collected for the MESA (Multi-Ethnic Study of Atherosclerosis) lung study [8], NHANES (National Health and Nutrition Examination Survey) III [2], NHANES IV [9] and the study by Wang et al. 10; ^§: Korea and China north of the Huaihe River and Qinling Mountains; ^ƒ: Thailand, Taiwan and China south of the Huaihe River and Qinling Mountains; ^##: individuals not represented by the other four groups in the study by Quanjer et al. [4].