Table 2.

Prevalence, incidence, remitted, and persistent proportions of airway symptoms in the study population (N = 5017)

Measure	Wheezea		Long-standing cougha		Productive cougha
	N	%	N	%	N	%
Baseline prevalence	936/5017	18.7	1086/5017	21.7	1000/5017	19.9
Cumulative incidence proportionb	341/(5017–936)	8.4	350/(5017–1086)	8.9	417/(5017–1000)	10.4
Annual incidence proportion	341/(5017–936)/6	1.4	350/(5017–1086)/6	1.5	417/(5017–1000)/6	1.7
Remitted proportionc	442/936	47.2	658/1086	60.6	468/1000	46.8
Annual remitted proportion	442/936/6	7.9	658/1086/6	10.1	468/1000/6	7.8
Persistent proportiond	(936–442)/936	52.8	(1086–658)/1086	39.4	(1000−468)/1000	53.2

^aThe figures are affected by item non-response, and absolute percentages are presented

^bThe number of incident cases divided by subjects at risk (total sample minus subjects with symptoms at baseline)

^cThe number of remitted cases divided by the number of subjects with symptoms at baseline

^dThe number of persistent cases (subjects with symptoms at baseline minus number of remitted cases) divided by the number of subjects with symptoms at baseline