Table 4.

Multivariable analysis of IGF-1 and asthma and asthma outcomes adjusting for metabolic syndrome

	All participants (n=253,718)	Women (n=135, 541)	Men (n=118, 177)
IGF-1 quartile (nmol/L)	Odds Ratio (95% Confidence Interval)
Asthma	n=29,146	n=16,463	n=12,683
Q1 (< 17.8)	1.0	1.0	1.0
Q2 (17.8– < 21.5)	0.94 (0.91–0.97)†	0.95 (0.91–0.99)*	0.92 (0.87–0.97)†
Q3 (21.5– < 25.0)	0.90 (0.87–0.93)†	0.92 (0.88–0.97)†	0.87 (0.82–0.92)†
Q4 (≥ 25.0)	0.88 (0.85–0.91)†‡	0.89 (0.85–0.94)†‡	0.85 (0.81–0.90)†‡
Participants with asthma
Wheeze in the last year	n=18,824	n=10,587	n=8,237
Q1 (< 17.4)	1.0	1.0	1.0
Q2 (17.4– < 21.2)	0.87 (0.81–0.94)†	0.87 (0.80–0.96)†	0.87 (0.77–0.97)*
Q3 (21.2– < 24.8)	0.89 (0.82–0.95)†	0.90 (0.82–0.99)*	0.86 (0.77–0.97)*
Q4 (≥ 24.8)	0.87 (0.81–0.94)†‡	0.91 (0.83–1.01)	0.83 (0.74–0.93)†‡
At least one asthma -related hospitalization	n=896	n=590	n=306
Q1 (< 17.4)	1.0	1.0	1.0
Q2 (17.4- < 21.2)	0.99 (0.82–1.20)	0.94 (0.75–1.19)	1.12 (0.78–1.60)
Q3 (21.2- < 24.8)	1.21 (0.99–1.46)	1.14 (0.91–1.44)	1.37 (0.96–1.92)
Q4 (≥ 24.8)	1.01 (0.83–1.24)	0.91 (0.71–1.17)	1.23 (0.86–1.76)

Abbreviation: IGF-1, insulin-like growth factor 1

All models adjusted for age, sex (in all participants), ethnicity, annual household income, body mass index, smoking status, pack-years of cigarette smoking, the season of the examination, the time of the day when the examination was performed, serum level of glycated hemoglobin A1c, C-reactive protein, and metabolic syndrome. Analyses stratified by sex, given evidence of effect modification (P for interaction=0.01).

^*P <0.05

^†P <0.01

^‡P for trend <0.05