Table 3 Results of regression analysis showing the coefficients for all variables on FEV₁

Time point	Variable	Category	Unadjusted coefficient (95% CI)	p Value		Adjusted coefficient (95% CI)	p Value
Fetal	Social class at birth*	I, II	Reference		Total for variable: 0.096
		III	−0.222 (−0.470 to 0.025)	0.078
		IV, V	−0.296 (−0.565 to −0.027)	0.031
	Housing conditions at birth†	012	Reference−0.133 (−0.316 to 0.051)−0.050 (−0.271 to 0.170)	0.1560.652	Total for variable: 0.506
		⩾3	−0.110 (−0.353 to 0.133)	0.375
	Standardised birth weight‡ (z score)		0.047 (−0.024 to 0.118)	0.191		0.067 (0.016 to 0.119)	0.011

Childhood	Had measles between ages 0 and 5	No	Reference	0.090
		Yes	−0.129 (−0.278 to 0.020)
	Had influenza between ages 0 and 5	No	Reference
		Yes	0.188 (−0.211 to 0.586)	0.355
	Had whooping cough between ages 0 and 5	No	Reference
		Yes	−0.053 (−0.202 to 0.097)	0.487
	Had tuberculosis between ages 0 and 5	No	Reference
		Yes	0.004 (−0.311 to 0.319)	0.979
	Breast fed for less than 4 weeks	No	Reference			Reference
		Yes	−0.245 (−0.416 to −0.074)	0.005		−0.148 (−0.269 to −0.027)	0.017
	Total colds during ages 0 and 5		0.013 (−0.014 to 0.041)	0.347
	Total URTIs during ages 0 and 5		−0.026 (−0.064 to 0.012)	0.183
	Total LRTIs during ages 0 and 5		−0.072 (−0.133 to −0.011)	0.021		−0.049 (−0.088 to −0.009)	0.015

Adulthood	Social class at 49–51*	I, II	Reference
		III	−0.124 (−0.287 to 0.039)	0.135	Total for variable: 0.168
		IV, V	−0.178 (−0.407 to 0.050)	0.125	Total for variable: 0.168
	Cigarette smoking status§	None	Reference		Total for variable: <0.001	Reference
		Ex	0.113 (−0.056 to 0.282)	0.188		−0.061 (−0.177 to 0.056)	0.306	Total for variable: <0.001
		Current	−0.309 (−0.486 to −0.132)	0.001		−0.288 (−0.421 to −0.154)	<0.001	Total for variable: <0.001
	Alcohol consumption§	None	Reference		Total for variable: 0.077
		Light	0.282 (0.031 to 0.534)	0.028
		Moderate	0.331 (0.080 to 0.583)	0.010
		Heavy	0.304 (−0.040 to 0.648)	0.084
	Physical activity§	None	Reference		Total for variable: 0.004
		Low	0.388 (0.152 to 0.624)	0.001
		Medium	0.447 (0.185 to 0.709)	0.001
		High	0.438 (0.157 to 0.719)	0.002
	Occupational exposure¶	Normal	Reference
		Increased	0.698 (0.506 to 0.890)	<0.001
	Had LRTI during last 3 years§	No	Reference
		Yes	−0.301 (−0.513 to −0.089)	0.005
	Current β blocker usage	No	Reference
		Yes	−0.178 (−0.506 to 0.150)	0.287
	Cigarette smoking history (pack-years)		−0.002 (−0.007 to 0.003)	0.515
	Body fat (%)		−0.025 (−0.033 to −0.017)	<0.001		−0.008 (−0.014 to −0.002)	0.010

General	Sex	Male	Reference			Reference
		Female	−0.951 (−1.071 to −0.830)	<0.001		−0.609 (−0.763 to −0.455)	<0.001
	Ever diagnosed with asthma**	No	Reference			Reference
		Yes	−0.313 (−0.534 to −0.091)	0.006		−0.199 (−0.356 to −0.041)	0.013
	Height (cm)		0.054 (0.047 to 0.061)	<0.001		0.022 (0.012 to 0.032)	<0.001
	Height² (cm² ×10³) (difference from mean)		1.321 (0.332 to 2.310)	0.009		0.758 (0.026 to 1.491)	0.043

Adjusted coefficients are shown for variables included in the adjusted model.
*As defined by the UK Registrar General’s Standard Occupational Classification, where I is the most advantaged.
†From 0 to 3 or more of: overcrowding, lack of hot water, shared toilet and dampness or poor repair.
‡Adjusted for sex and gestational age.13
§Self reported.
¶Ever employed in an occupation with an increased risk of exposure to asbestos, dust or fumes.16
**Self-reported or abstracted from early records.
FEV₁, forced expiratory volume in 1 s; LRTIs, lower respiratory tract infections; URTIs, upper respiratory tract infections, excluding colds.