Figures
- FIGURE 1
STROBE Study flow chart.
- FIGURE 2
Age-specific prevalence of chronic cough.
- FIGURE 3
Age-specific incidence of chronic cough. PY: person-years.
Tables
- TABLE 1
Baseline characteristics of the study population
Baseline characteristics Total Chronic cough cases Non-cases p-value Subjects n 9824 1073 8751 Age years 66.0±10.8 67.8±10.6 65.8±10.8 0.392 Age ≥70 years No 6118 (62.3) 579 (54.0) 5539 (63.3) <0.001 Yes 3706 (37.7) 494 (46.0) 3212 (36.7) Age (decades) 5th 570 (5.8) 39 (3.6) 531 (6.1) <0.001 6th 2297 (23.4) 209 (19.5) 2088 (23.9) 7th 3251 (33.1) 331 (30.8) 2920 (33.4) 8th 2453 (25.0) 338 (31.5) 2115 (24.2) ≥9th 1253 (12.8) 156 (14.5) 1097 (12.5) Female sex 5725 (58.3) 639 (59.6) 5086 (58.1) 0.369 Smoking Never 3133 (31.9) 268 (25.0) 2865 (32.8) <0.001 Past 4915 (50.0) 475 (44.3) 4440 (50.8) Current 1769 (18.0) 329 (30.7) 1440 (16.5) BMI kg·m−2 27.1 (24.7–29.9) 27.2 (24.6–30.4) 27.0 (24.7–29.8) 0.475 Obesity 2114 (21.5) 240 (22.4) 1874 (21.4) 0.154 ACE inhibitors 1837 (18.7) 244 (22.7) 1593 (18.2) <0.001 Comorbidities 2420 (24.6) 480 (44.7) 1940 (22.2) <0.001 Chronic rhinosinusitis 289 (2.9) 57 (5.3) 232 (2.7) <0.001 GORD 1324 (13.5) 196 (18.3) 1128 (12.9) <0.001 Asthma 522 (5.3) 124 (11.6) 389 (4.5) <0.001 COPD 646 (6.6) 213 (19.9) 433 (4.9) <0.001 ACO 21 (0.2) 6 (0.6) 15 (0.2) 0.009 Data are presented as mean±sd, n (%) or median (interquartile range), unless otherwise stated. BMI: body mass index; ACE: angiotensin converting enzyme; GORD: gastro-oesophageal reflux disease; COPD: chronic obstructive pulmonary disease; ACO: asthma–COPD overlap.
- TABLE 2
Baseline prevalence of chronic cough
Baseline characteristics Subjects at risk n Prevalent chronic cough n Prevalence % (95% CI) p-value Study Population 9824 1073 10.9 (10.3–11.6) Sex Male 4099 434 10.6 (9.7–11.6) 0.369 Female 5725 639 11.2 (10.4–12.0) Age ≥70 years No 6118 579 9.5 (8.7–10.2) <0.001 Yes 3706 494 13.3 (12.3–14.5) Age <70 years Male 2640 224 8.5 (7.4–9.6) 0.023 Female 3478 355 10.2 (9.2–11.3) Smoking status Never 3133 268 8.6 (7.6–9.6) <0.001 Past 4915 475 9.7 (8.9–10.5) Current 1769 329 18.6 (16.8–20.5) ACE-inhibitors Non-users 7987 829 10.4 (9.7–11.1) <0.001 Users 1837 244 13.3 (11.8–14.9) Obesity No 6618 679 10.3 (9.5–11.0) 0.154 Yes 2114 240 11.4 (10.0–12.8) ACE: angiotensin converting enzyme
- TABLE 3
Incidence rate of chronic cough in participants with complete follow up
Baseline characteristics At risk n Incident chronic cough n Total follow-up years Incidence rate per 1000 person-years (95% CI) Incidence rate ratio (95% CI) Participants 6245 439 37 737 11.6 (10.6–12.8) Sex Male 2634 190 15 887 12.0 (10.3–13.8) Ref. Female 3611 249 21 850 11.4 (10.0–12.9) 0.95 (0.79–1.16) Age ≥70 years No 4546 318 26 811 11.9 (10.6–13.2) Ref. Yes 1699 121 10 926 11.1 (9.2–13.2) 0.93 (0.75–1.15) Smoking status Never 2060 129 12 427 10.4 (8.7–12.3) Ref. Past 3216 216 19 559 11.0 (9.7–12.6) 1.06 (0.85–1.33) Current 968 94 5746 16.4 (13.4–20.0) 1.57 (1.20–2.07) Current smokers Female 579 41 3435 11.9 (8.6–16.2) Ref. Male 389 53 2311 22.9 (17.2–30.0) 1.92 (1.25–2.96) Obesity No 4549 299 27 517 10.9 (9.7–12.2) Ref. Yes 1440 120 8676 13.8 (11.5–16.5) 1.27 (1.02–1.58) - TABLE 4
Incidence rate of chronic cough in all eligible participants
Baseline characteristics At risk n Incident chronic cough n Total follow-up years Incidence rate per 1000 person-years (95% CI) Incidence rate ratio (95% CI) Total participants n 8751 439 52 817 8.3 (7.6–9.1) Sex Male 5086 249 31 136 8.0 (7.0–9.1) Ref. Female 3665 190 21 681 8.8 (7.6–10.1) 1.09 (0.90–1.33) Age ≥70 years No 4546 318 33 157 11.9 (10.6–13.2) Ref. Yes 1699 121 19 660 11.1 (9.2–13.2) 0.64 (0.52–0.79) Smoking status Never 2865 129 17 630 7.3 (6.1–8.7) Ref. Past 4440 216 26 736 8.1 (7.0–9.2) 1.10 (0.88–1.38) Current 1440 94 8433 11.2 (9.0–13.6) 1.52 (1.16–2.00) Current smokers Female 857 41 5077 8.1 (5.8–11.0) Ref. Male 583 53 3355 15.8 (11.8–20.7) 1.96 (1.28–3.02) Obesity No 5939 299 36 036 8.3 (7.4–9.3) Ref. Yes 1874 120 11 496 10.4 (8.7–12.5) 1.26 (1.01–1.56) - TABLE 5
Risk factors for chronic cough
Variables Incident chronic cough No chronic cough OR (95% CI) (crude) Model 1 OR (95% CI) (adjusted) Model 2 OR (95% CI) (adjusted) Subjects n 439 5806 Age years NA NA 1.00 (0.99–1.01) #1.01 (0.99–1.02) 1.00 (0.99–1.01) Female sex 249 3362 0.95 (0.78–1.16) ¶0.95 (0.78 –1.16) 0.90 (0.73–1.10) Past smokers 216 3000 1.08 (0.86–1.35) 1.06 (0.84–1.34) 1.00 (0.79–1.27) Current smokers 94 874 1.61 (1.22–2.13) 1.63 (1.23–2.16) 1.64 (1.22–2.19) Obesity 120 1320 1.29 (1.04–1.61) 1.30 (1.04–1.62) 1.24 (0.99–1.55) CRS 16 161 1.33 (0.79–2.24) 1.34 (0.79–2.26) 0.96 (0.54–1.69) GORD 71 695 1.42 (1.09–1.85) 1.42 (1.09–1.86) 1.34 (1.01–1.78) OAD 88 480 2.78 (2.16–3.58) 2.79 (2.17–3.60) 2.75 (2.12–3.58) Asthma 51 272 2.67 (1.95–3.67) 2.73 (1.98–3.75) 2.88 (2.07–4.02) COPD 35 200 2.43 (1.67–3.53) 2.42 (1.66–3.53) 2.52 (1.70–3.71) Model 1: adjusted for age and sex; model 2 (full model): adjusted for age, sex, smoking, obesity, chronic obstructive pulmonary disease (COPD), asthma, gastro-oesophageal reflux disease (GORD) and chronic rhinosinusitis (CRS). Asthma-COPD overlap (ACO) was omitted from the analyses due to low power (10 subjects). OAD: obstructive airway disease (asthma, COPD and ACO). #: adjusted for sex and smoking. ¶: adjusted for age and smoking.
