First author [Ref.] (country) | Subjects# n | Age yrs | Population(s) | Period | AHR criterion | Notes |
Positive correlation between ageing and AHR |
Hopp 23 | 148 | 5–86 | HSs | 1972–1983 | PD20,MCh | Small number of subjects |
(USA) | (11>67 yrs) | | | | | |
Sparrow 24 | 914 | 41–86 | HSs | 1984–1987 | PD20,MCh | Only male subjects; no change after adjustment for FEV1 |
(USA) | (110>70 yrs) | | | | | |
Sparrow 25 | 435 | 60.3±7 | HSs | 1985–1991 | PD20,MCh | Only male subjects; no change after adjustment for FEV1 |
(USA) | | | | | | |
Xu 26 | 10284 | 8–74 | Random | 1995–1998 | PD20,MCh | No difference between PD20,BL and PD20,sal |
(China) | (1859>45 yrs) | | | | | |
Renwick 27 (UK) | 208 (103>65 yrs) | 45–86 | Random white adults | 12 months | PD20,MCh | Only subjects aged >45 yrs; strong dependence on FEV1 |
Rijcken 21 | 1905 | 14–>64 | Urban; rural | 1970–1984 | PC10,HA | No change after adjustment for FEV1 |
(The Netherlands) | (15>64 yrs) | | | | | |
Rijcken 22 | 2216 | 15–72 | Urban; rural | 1970–1987 | PC10,HA | No change after exclusion of respiratory symptoms |
(The Netherlands) | | | | | | |
O'Connor 28 | 778 | 41–86 | HSs | 1984–1987 | PD20,MCh | Only male subjects; no change after adjustment for FEV1 |
(USA) | | | | | | |
Paoletti 29 | 1558 | 8–73 | Random | 1980–1991 | PD20,MCh | Strong dependence on FEV1 |
(Italy) | (38>66 yrs) | | | | | |
Burney 30 (UK) | 511 (80>55 yrs) | 18–64 | Random | 1984 | PD20,HA | Lack of subjects aged >65 yrs; strong dependence on smoking; no change after adjustment for FEV1 |
Negative correlation between ageing and AHR |
Bakke 31 | 490 | 18–73 | Random | 1985–1988 | PC20,MCh | Strong dependence on FEV1 |
(Norway) | (136>55 yrs) | | | | | |
Britton 32 | 2415 | 18–70 | Random | 1991 | PD20,MCh | Strong dependence on FEV1 |
(UK) | (348>60 yrs) | | | | | |
Schwartz 33 (Switzerland) | 7126 | 18–60 | Random | NA | PD20,MCh | Lack of subjects aged >60 yrs; no change after adjustment for respiratory symptoms and FEV1 |
No correlation between ageing and AHR |
Woolcock 34 | 876 | 18–78 | Rural | 1981 | PD20,HA | Strong association with respiratory symptoms |
(Australia) | (291>60 yrs) | | | | | |
Malo 35 | 100 | 20–60 | HSs | 1981–1982 | PC20,MCh | Small number of subjects; lack of subjects over 60 yrs |
(Canada) | | | | | | |
Cerveri 20 | 654 | 15–64 | Random | 1985–1986 | PD15,MCh | Lack of subjects over 65 yrs |
(Italy) | | | | | | |
Trigg 36 | 318 | 18–75 | Random | 1982–1987 | PC20,MCh | Trend of increase in AHR with age |
(UK) | (27>65 yrs) | | | | | |
Higgins 37 | 202 | 18–65 | Random | NA | PD20,MCh | Interaction with smoking and atopy |
(UK) | | | | | | |