Table 4

Associations between vigorous physical activity variables at the first examination and lung function and decline*

Vigorous physical activity levels	N	FEV₁ (mL)			FVC (mL)
Vigorous physical activity levels	N	Mean difference	95% CI	N	Mean difference	95% CI
Association with lung function†
Frequency
≤1 a month	3887	Reference		3872	Reference
1–3 times a week		13.2	−20.3 to 46.6		16.9	−21.2 to 55.1
≥4 times a week		12.3	−35.9 to 60.4		59.3	4.4 to 114.3
Duration (per week)
≤30 min	3857	Reference		3842	Reference
1–3 hours		20.8	−13.2 to 54.8		13.5	−25.3 to 52.3
≥4 hours		39.3	−5.9 to 84.6		73.9	22.4 to 125.4
Active
≥2 times and ≥1 hour per week	3855	43.6	12.0 to 75.1	3840	53.9	17.8 to 89.9
Association with rate of lung function decline‡
Frequency
≤1 a month	3887	Reference		3872	Reference
1–3 times a week		1.6	−0.3 to 3.4		0.1	−2.2 to 2.5
≥4 times a week		−0.3	−2.9 to 2.4		−1.5	−4.9 to 2.0
Duration (per week)
≤30 min	3857	Reference		3842	Reference
1–3 hours		2.3	0.4 to 4.1		1.7	−0.7 to 4.1
≥4 hours		1.4	−1.1 to 3.9		1.9	−1.4 to 5.1
Active
≥2 times and ≥1 hour per week	3855	1.4	−0.3 to 3.2	3840	−0.3	−2.6 to 2.0

Bold indicates P value <0.05.
*Adjusted for sex, age, age-squared, height, weight, smoking status, second-hand smoke exposure, education and occupation. An interaction term between time between follow-ups and the physical activity parameter was included to capture the effect of physical activity on lung function decline.
†A positive estimate suggests that those more active at the first examination had higher average lung function at both examinations than those less active.
‡A positive estimate suggests that those more active at the first examination had a smaller decline in lung function between the two examinations than those less active.
N, number of participants included in the model.