Poor Asthma Control in Schoolchildren May Lead to Lower Lung Function Trajectory from Childhood to Early Adulthood: A Japanese Cohort Study

Figures & data

Figure 1 Study design.

Table 1 Between-Group Comparisons of Characteristics in Girls and Boys at the Age of 6 Years

Characteristics	Girls, n = 197			Boys, n = 308
	Poor Control Group, n = 81	Good Control Group, n = 116	P value	Poor Control Group, n = 133	Good Control Group, n =175	P value
Height, cm	112.4 ± 5.4, n = 37	114.1 ± 5.4, n = 28	0.2	114.3 ± 5.9, n = 61	114.6 ± 4.9, n = 41	0.8
Weight, kg	19.1 ± 3.0, n = 36	20.1 ± 2.8, n = 28	0.2	19.4 ± 2.8, n = 60	20.8 ± 3.4, n = 40	0.0246*
Body mass index, kg/m^2	15.1 ± 1.6, n = 36	15.6 ± 1.4, n = 27	0.3	14.9 ± 1.4, n = 60	15.8 ± 2.0, n = 40	0.0057*
Lung function tests
FVC, L	1.15 ± 0.24, n = 21	1.20 ± 0.33, n = 13	0.6	1.32 ± 0.31, n = 34	1.28 ± 0.24, n = 26	0.6
%FVC predicted, %	92.4 ± 19.2, n = 21	100.0 ± 23.8, n = 13	0.3	90.3 ± 15.7, n = 34	90.4 ± 14.1, n = 26	1.0
FEV1, L	0.90 ± 0.27, n = 21	0.93 ± 0.26, n = 13	0.6	0.94 ± 0.25, n = 35	1.09 ± 0.17, n = 26	0.1
%FEV1 predicted, %	78.0 ± 22.6, n = 21	84.1 ± 20.7, n = 13	0.4	74.0 ± 15.1, n = 35	84.3 ± 11.6, n = 26	0.0048*
FEV1/FVC ratio	0.77 ± 0.13, n = 21	0.78 ± 0.12, n = 13	0.7	0.77 ± 0.14, n = 34	0.87 ± 0.11, n = 26	0.0047*
No. of children with ventilatory patterns, n (%)
Restrictive	2 (9.5), n = 21	2 (15.4), n = 13	0.6	7 (20.6), n = 34	6 (23.1), n = 26	1.0
Obstructive	7 (33.3), n = 21	4 (30.8), n = 13	1.0	13 (38.2), n = 34	2 (7.7), n = 26	0.0076*
Mixed	4 (19.1), n = 21	1 (7.7), n = 13	0.6	1 (2.9), n = 34	0 (0), n = 26	1.0

Notes: Data were expressed as mean ± SD and number (%) of children. The poor control group had significantly lower mean scores (± SD, points) of the asthma control level in girls (2.95 ± 0.46, n = 39) (P < 0.0001) and boys (3.16 ± 0.37, n = 67) (P < 0.0001) compared with the good control group (4.0, n = 30 and 4.0, n = 46, respectively) at the age of 6 years. n = number of children tested. *P < 0.05 for between-group comparisons.

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; SD, standard deviation.

Figure 2 Between-group comparisons of lung functions in girls and boys from the ages of 6 years to 17 years.

Notes: %FVC predicted, %FEV₁ predicted, and FEV₁/FVC ratio in Girls (A) and Boys (B). The poor and good control groups are shown in red and blue, respectively. The mean and SD are shown in open circles and pale-colored squares, respectively. We performed between-group comparisons of the mean values of %FVC predicted, %FEV₁ predicted, and FEV₁/FVC ratio in the two age groups (ages: 6–11 years and 12–17 years).

Figure 3 Between-group comparison of the slopes for lung function growth in girls and boys from the ages of 6 years to 17 years.

Notes: %FVC predicted, %FEV₁ predicted, and FEV₁/FVC ratio in Girls (A) and Boys (B). The slopes with poor and good control groups are shown in red and blue lines, respectively. We performed between-group comparisons of the slopes of %FVC predicted, %FEV₁ predicted, and FEV₁/FVC ratio growth in the two age groups (ages: 6–11 years and 12–17 years).

Figure 4 Between-group comparisons of lung functions in girls and boys in early adulthood.

Notes: Data were expressed as a percentage of the patients with restrictive, obstructive, and mixed ventilatory pattern among girls (A) and boys (B) between the ages of 18 and 20 years, respectively.

Figure 5 Between-group comparisons of lung functions at either 6 or 7 years in girls and boys.

Notes: Data were expressed as a percentage of the patients with restrictive, obstructive, and mixed ventilatory pattern among girls (A) and boys (B) at either 6 or 7 year, respectively. On an average, poor and good asthma control levels were scored <4.0 and 4.0 of the scoring system under 6years by the Act, respectively.