Table 4:

Final multivariate model obtained with backwards variable selection for significant, independent determinants in early life for adult spirometric patterns across years 22–36 in TCRS

		N subjects	Adult Restrictive Spirometric Pattern		Adult Obstructive Spirometric Pattern
			RRR (95% CI)*	p value	RRR (95% CI)*	p value
Nutritional problems during pregnancy	No	282	ref
	Yes	101	2·48 (1·30, 4·76)	0·006	1·40 (0·70, 2·79)	0·34
Size for gestational age	AGA	319	ref
	SGA	31	3·26 (1·34, 7·93)	0·009	1·11 (0·44, 2·83)	0·82
	LGA	33	0·68 (0·18, 2·55)	0·56	1·73 (0·63, 4·74)	0·28
Childhood nutritional status across Years 6–16	Normal weight	224	ref
	Underweight	24	3·54 (1·35, 9·26)	0·010	1·32 (0·41, 4·25)	0·65
	Overweight	60	1·58 (0·69, 3·63)	0·28	1·55 (0·62, 3·90)	0·35
	Obese	75	1·08 (0·50, 2·32)	0·84	0·79 (0·32, 1·94)	0·60
Childhood asthma across Years 6–16	No	279	ref
	Yes	104	1·54 (0·78, 3·04)	0·21	2·70 (1·29, 5·63)	0·008

The final model included 1,023 lung function observations from years 22, 26, 32, and 36 (814 with normal, 106 with restrictive, and 103 with obstructive spirometric pattern) from 383 participants. Initial model included significant predictors of adult spirometric restriction and/or obstruction from univariate analyses: maternal nutritional problems during pregnancy, maternal age, maternal asthma, paternal smoking, birthweight, ponderal index, size for gestational age, childhood nutritional status, and childhood asthma. Significant predictors were retained by backward selection at p <0·050. Survey year, sex, and race/ethnicity were also included in the model as a priori forced covariates.

^*Relative risk ratios (RRRs) are from multinomial logistic regression models. Normal spirometric pattern as the reference group. AGA=appropriate for gestational age. SGA=small for gestational age. LGA=large for gestational age. ref=reference category. Significant associations are reported in bold font.