Relative risk of severe dementia syndrome according to different sources of ETS exposure and cumulative exposure in the five-province study, China
| Severe dementia syndromes | ||||||
|---|---|---|---|---|---|---|
| All participants (n=5921) | Never smokers (n=3769) | |||||
| ETS exposure | RR* | 95% CI | p Value | RR* | 95% CI | p Value |
| Exposure source | ||||||
| At home | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.01 | 0.67 to 1.51 | 0.978 | 0.89 | 0.43 to 1.81 | 0.739 |
| Yes† | 1.35 | 1.11 to 1.64 | 0.002 | 1.39 | 1.08 to 1.79 | 0.010 |
| At work | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.15 | 0.94 to 1.40 | 0.161 | 1.11 | 0.76 to 1.64 | 0.585 |
| Yes† | 1.59 | 1.02 to 2.48 | 0.039 | 1.98 | 1.21 to 3.24 | 0.006 |
| In other locations | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.19 | 1.08 to 1.31 | 0.001 | 1.20 | 0.90 to 1.60 | 0.210 |
| Yes† | 1.41 | 1.00 to 1.98 | 0.051 | 1.53 | 0.97 to 2.39 | 0.065 |
| Above 3 combined‡ | ||||||
| None | 1.00 | 1.00 | ||||
| Some (1–2)‡ | 1.22 | 1.06 to 1.40 | 0.005 | 1.22 | 0.94 to 1.57 | 0.130 |
| A lot (3–6)‡ | 1.67 | 1.25 to 2.24 | 0.001 | 2.02 | 1.59 to 2.58 | <0.001 |
| Exposure duration (years) | ||||||
| At home | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.00 | 0.67 to 1.49 | 0.999 | 0.88 | 0.44 to 1.78 | 0.724 |
| >0–19 | 1.12 | 0.84 to 1.48 | 0.440 | 1.32 | 0.88 to 1.98 | 0.177 |
| 20–39 | 1.20 | 1.00 to 1.43 | 0.049 | 1.17 | 0.92 to 1.48 | 0.196 |
| ≥40 | 1.65 | 1.21 to 2.27 | 0.002 | 1.70 | 1.28 to 2.27 | <0.001 |
| At work | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.15 | 0.95 to 1.40 | 0.153 | 1.12 | 0.76 to 1.64 | 0.581 |
| >0–19 | 1.35 | 0.92 to 1.97 | 0.129 | 1.69 | 0.78 to 3.68 | 0.186 |
| 20–39 | 1.42 | 0.84 to 2.40 | 0.189 | 1.86 | 0.97 to 3.54 | 0.060 |
| ≥40 | 2.05 | 1.32 to 3.19 | 0.001 | 2.39 | 1.52 to 3.76 | <0.001 |
| In other locations | ||||||
| None | 1.00 | 1.00 | ||||
| No | 1.20 | 1.08 to 1.33 | 0.001 | 1.21 | 0.90 to 1.61 | 0.203 |
| >0–19 | 1.10 | 0.76 to 1.59 | 0.630 | 1.48 | 1.10 to 1.99 | 0.009 |
| 20–39 | 1.32 | 0.86 to 2.04 | 0.209 | 1.18 | 0.54 to 2.59 | 0.682 |
| ≥40 | 1.93 | 1.37 to 2.72 | <0.001 | 2.21 | 1.53 to 3.18 | <0.001 |
| Above 3 combined score§ | ||||||
| None | 1.00 | 1.00 | ||||
| 1 | 1.17 | 0.79 to 1.72 | 0.433 | 1.29 | 0.73 to 2.30 | 0.381 |
| 2 | 0.96 | 0.78 to 1.18 | 0.707 | 0.85 | 0.56 to 1.31 | 0.475 |
| 3–4 | 1.31 | 1.03 to 1.69 | 0.031 | 1.33 | 0.95 to 1.86 | 0.097 |
| 5–9 | 1.66 | 1.21 to 2.28 | 0.002 | 1.98 | 1.52 to 2.59 | <0.001 |
| Cumulative dose (level×duration)¶ | ||||||
| None | 1.00 | 1.00 | ||||
| >0–24 | 0.99 | 0.76 to 1.28 | 0.919 | 0.94 | 0.60 to 1.50 | 0.809 |
| 25–49 | 1.15 | 0.93 to 1.42 | 0.199 | 1.11 | 0.82 to 1.51 | 0.502 |
| 50–74 | 1.18 | 0.87 to 1.59 | 0.281 | 1.16 | 0.76 to 1.79 | 0.488 |
| 75–99 | 1.39 | 1.03 to 1.84 | 0.028 | 1.34 | 0.76 to 2.36 | 0.305 |
| ≥100 | 1.95 | 1.34 to 2.83 | <0.001 | 2.55 | 1.67 to 3.90 | <0.001 |
*Adjusted for age, sex, smoking status, urban/rural location, educational level, occupation, income, marital status, religion, current drinking, visiting children or relatives, hypertension, stroke and depressive syndrome, and taking account of the five-province geographical area clustering.
†Including participants with ‘yes, some’ or ‘yes, a lot’ of ETS exposure.
‡Each participant had an overall score for total exposure from all three ETS sources. Exposure levels of ‘no, none at all’, ‘yes, some’ and ‘yes, a lot’ were scored as 0, 1 and 2, respectively. Therefore, a participant exposed to ETS ‘no, none at all’ at home, ‘yes, a lot’ at work and ‘yes, some’ in other locations, would have a total score of 3 (0+2+1).
§Participants with ETS exposure durations of 0, >0–19, 20–39 or ≥40 years were scored as 0, 1, 2 or 3 for each exposure source. Overall scores were the sum of the individual scores for the three sources of exposure.
¶Cumulative dose score calculated by multiplying exposure level by exposure duration (years) for each ETS source, and then combining the results for the three sources of exposure. Therefore, a participant exposed to ETS ‘yes, some’ at home for 20 years, ‘yes, a lot’ at work for 15 years, and ‘yes, some’ in other locations for 10 years, would have total score of 60 years (1×20+2×15+1×10).
“None” means “no ETS at all”. “No” means “not ETS exposure at either home, work or other places”