Table 2 Sociodemographic characteristics of the study sample
| Â | N (2398 at baseline) or mean (standard deviation) | Percentage |
|---|---|---|
Covariates | ||
Age | ||
 45–54 years | 840 | 35.3 |
 55–60 years | 767 | 31.8 |
  > 60 years | 791 | 32.9 |
Marital Status | ||
 Widowed, divorced, separated | 177 | 7.4 |
 Single | 122 | 5.1 |
 Married | 2099 | 87.5 |
Registrar General Social Class | ||
 Non-manual | 780 | 32.6 |
 Manual | 1610 | 67.4 |
Employment status | ||
 Employed | 1107 | 43.6 |
 Self-employed | 152 | 6.3 |
 Unemployed | 362 | 15.1 |
 Retired | 770 | 32.3 |
Smoking status | ||
 Non-smoker | 431 | 18.0 |
 Ex-smoker | 907 | 37.9 |
 Current smoker | 1054 | 44.1 |
 BMI | 26.4 (3.64) | Not applicable |
 Alcohol consumption ccs/week | 15,414 (199) | Not applicable |
 Physical activity | 130,252 (134355) | Not applicable |
Noise at work | ||
 1 | 747 | 32.1 |
 2 | 878 | 37.8 |
 3 | 700 | 30.1 |
Noise variables | ||
Noise exposure (LAeq 16 h) |  |  |
 51-55dBA | 2101 | 72.6 |
 56-60dBA | 247 | 8.5 |
 61-65dBA | 374 | 12.9 |
 66-70dBA | 174 | 6.0 |
Noise sensitivity | ||
 Lowest tertile | 808 | 34.6 |
 Mid tertile | 773 | 33.1 |
 Highest tertile | 753 | 32.3 |
Noise annoyance | ||
 Never, Seldom, Sometimes | 2262 | 96.4 |
 Often, Always | 84 | 3.6 |
Cardiovascular variables | ||
CHD prior to phase 2 | ||
 No | 2345 | 97.8 |
 Yes | 53 | 2.2 |
IHD mortality between phase 2 and phase 4 | ||
 No | 1976 | 82.4 |
 Yes | 422 | 17.6 |
IHD morbidity between phase 2 and phase 4 | ||
 No | 1659 | 69.2 |
 Yes | 739 | 30.8 |
Psychological variables | ||
GHQ2 | ||
 No | 7177 | 77.7 |
 Yes | 490 | 22.3 |
GHQ3 | ||
 No | 1319 | 76.2 |
 Yes | 410 | 23.8 |
GHQ4 | ||
 No | 1124 | 75.3 |
 Yes | 369 | 24.7 |