Introduction
Methods
Systematic review methods
Inclusion and exclusion criteria
Assessment of study quality
Results
Study ID | Type of Study | Included participants | Patient population | Assessment of SHS Exposure | Disease/Key Outcome | N-O Score |
---|---|---|---|---|---|---|
Health outcomes of non-smokers previously exposed to SHS in the home(Objective 1) | ||||||
Reading et al. 2008[16] | Longitudinal cohort | 11,332 families | Families recruited in the ASLPAC study | Parent-completed postal questionnaire | Accidents | 6 |
Isle of Wight Birth Cohort
| Longitudinal cohort | 1456 | Birth cohort | Parent-completed questionnaire | Asthma/wheeze outcomes | 7 |
Arshad et al. 2005[17] | 1,373 | Completed 10 year assessment | 6 | |||
Kurukulaaratchy et al. 2003[18] | 169 | Positive for bronchial hyper-responsiveness at age 10 | 6 | |||
Kurukulaaratchy et al. 2004[19] | 206 | Early or late onset persistent wheeze at age 10 | 6 | |||
Kurukulaaratchy et al. 2006[20] | 340 | Reported wheeze ever up to age 10 with atopic parents | 6 | |||
Tariq et al. 2000[21] | 1,218 | Completed 4 year assessment | 7 | |||
Hennessy et al. 2008[22] | Longitudinal cohort | 283 | Babies born at 25 weeks gestation or less | Parent-completed questionnaire | Wheeze | 7 |
Murray et al. 2004[23] | Longitudinal cohort | 369 | Child (<3 yrs) of parents with high risk of atopy | Interviewer administered respiratory questionnaire | Wheeze | 6 |
Trinder et al. 2000[24] | Cross-sectional survey | 2996 | Adults (16+ yrs) | Patient-completed questionnaire | Respiratory symptoms | 5 |
Chen et al. 2001[25] | Cross sectional survey | 301 | Never smoker adults (25–64 yrs) | Patient-completed questionnaire | Lung Function | 4 |
Palmer et al. 2004[26] | Cross-sectional study | 499 | Child (3–21 yrs) diagnosed with asthma | Parent-completed questionnaire | Asthma | 4 |
Gee et al. 2005[27] | Case–control study | 95 controls | Child (4–16 yrs) | Air sampling (RSPs, tobacco specific particles, VOCs, NO2, formaldehyde) | Asthma | 5 |
105 cases | ||||||
Forbes et al. 2007[28] | Case–control study | 394 controls | Child (3–14 yrs) | Parent-completed questionnaire | Asthma; Accident & Emergency attendance | 5 |
1018 cases | ||||||
Crombie et al. 2001[29] | Cross-sectional study | 501 families/ | Child (2–12 yrs) diagnosed with asthma | Saliva cotinine assessment; parent-completed questionnaire | Asthma | 4 |
438 children | ||||||
Ward et al. 2007[30] | Longitudinal retrospective cohort | 16,756 parents | Neonates | Parent interview | Birth weight | 7 |
Macdonald Wallis et al. 2011[31] | Longitudinal cohort | 7121 | Birth cohort | Parent-completed questionnaire | Bone characteristics | 8 |
Roddam et al. 2007[32] | Case–control study | 640 controls | Woman (aged 36–45 years) diagnosed with breast cancer from 1987-1990 | Patient interview | Breast cancer | 4 |
639 cases | ||||||
Llewellyn et al. 2009[33] | Cross-sectional survey | 4809 | Non-smoking adults (>50 years) | Saliva cotinine | Cognitive impairment | 5 |
Williams et al. 2000[34] | Cross-sectional survey | 763 | Child (1.5-4.5 years) | Parent-completed questionnaire | Dental caries | 4 |
MacLennan et al. 2006[35] | Longitudinal cohort | 13919 | Adolescent (15–19 years) | Patient interview | Meningococcal carriage | 6 |
Coen et al. 2006[36] | Case–control study | 144 survivors 144 matched controls | Adolescent (15–19 yrs) | Patient interview | Meningococcal disease | 4 |
Risk of future smoking in children exposed to second hand smoke in the home(Objective 2) | ||||||
Milton et al. 2004[37] | Longitudinal cohort | 247 at aged 9 | Primary school children aged 9-11 | Both child and parent (usually mother) postal questionnaires | Smoking behaviour assessed by self-completed questionnaire | 9 |
257 at aged | ||||||
10 | ||||||
239 at aged 11 | ||||||
Griesbach et al. 2003[38] | Cross-sectional survey | 3132 | Adolescents aged 15+ from Scotland (N = 1724) and Wales (N = 1408) | Self-completed questionnaire on parents and other smokers in the home | Smoking behaviour assessed by self-completed questionnaire | 4 |
The impact of past and current exposure to secondhand smoke in the home
Accidents
Study ID | N | Outcome | OR/RR for SHS exposure compared to non-exposure | P value | |
---|---|---|---|---|---|
Accidents
| |||||
Reading et al. 2008[16] | 11,332 families | For maternal smoking vs. non-smoking: | |||
All accidents | RR 1.17, 95% CI 1.12-1.23 | <0.01 | |||
Medically attended accidents | RR 1.23, 95% CI 1.14-1.32 | <0.01 | |||
Asthma and Related Symptoms
| |||||
Isle of Wight Birth Cohort
| |||||
Arshad et al. 2005[17] | 1,373 | Asthma at age 10 by parental smoking at age 1 vs. non-smoking | OR 1.99; 95% CI 1.15-3.45, | 0.014 | |
Wheeze at age 10 by parental smoking at age 4 vs. non-smoking | OR 2.18; 95% CI 1.25-3.81 | 0.006 | |||
Kurukulaaratchy et al. 2003[18] | 169 | Bronchial hyper-responsiveness at 10 years by parental smoking at age 4 vs. non-smoking | OR 2.62, 95% CI 1.03-6.71 | 0.04 | |
Kurukulaaratchy et al. 2004[19] | 206 | Early-onset persistent wheeze at age 10 vs. no parental smoking: | by parental smoking at birth | OR 1.88, 95% CI 1.27-2.77 | 0.001 |
by parental smoking at 1 year | OR 2.05, 95% CI 1.39-3.02 | <0.001 | |||
by parental smoking at 2 years | OR 2.00, 95% CI 1.33-3.00 | 0.001 | |||
by parental smoking at 4 years | OR 2.25, 95% CI 1.52-3.32 | <0.001 | |||
Kurukulaaratchy et al. 2006[20] | 340 | Wheeze ever vs. no parental smoking | by parental smoking at 1 years | OR 1.54, 95% CI 1.07-2.22 | 0.02 |
by parental smoking at 2 years | OR 1.51, 95% CI 1.04-2.21 | 0.03 | |||
by parental smoking at 4 years | OR 1.80, 95% CI 1.25-2.58 | 0.001 | |||
Tariq et al. 2000[21] | 1,218 | Asthma at 4 years by exposure to SHS in the home in early childhood vs. no exposure | OR 1.2, 95% CI 0.3-2.7 | NR | |
Any allergic hypersensitivity at 4 years by exposure to SHS in the home in early childhood vs. no exposure | OR 1.1, 95% CI 0.6-1.6 | NR | |||
Other studies
| |||||
Hennessy et al. 2008[22] | 219 | Any wheeze at 6 years by exposure at 30 months vs. no exposure | OR 2.04, 95% CI 1.10-3.81 | 0.024 | |
218 | Exercise-induced wheeze at 6 years by exposure at 30 months vs. no exposure | OR 2.14, 95% CI 1.11-4.12 | 0.022 | ||
219 | Night cough at 6 years by exposure at 30 months vs. no exposure) | OR 1.62, 95% CI 0.91-2.87 | 0.098 | ||
Murray et al. 2004[23] | 369 | For mother smoking postnatally vs. non-smoking | |||
Wheeze ever | OR 1.93, 95% CI 1.10-3.38 (adjusted analysis) | 0.02 | |||
Wheeze in first year | OR 1.79, 95% CI 1.05-3.08 (adjusted analysis) | 0.03 | |||
Trinder et al. 2000[24] | 2996 | Severe respiratory symptoms | OR 1.4, 95% CI 1.0-1.8 | NR | |
Chen et al. 2001[25] | 301 | Lung function: mean residuals of FEV1 and FVC | NR | >0.05 | |
Palmer et al. 2006[26] | 504 | Lung function | NR | >0.05 | |
Gee et al. 2005[27] | 95 controls | Difference in indoor pollutant levels between asthma cases and controls | NR | >0.05 for all pollutants | |
105 cases | |||||
Forbes et al. 2007[28] | 394 controls | A&E attendance in asthma patients | OR 1.12, 95% CI 0.80-1.58 (adjusted analysis) | NR | |
1018 cases | |||||
Crombie et al. 2001[29] | 501 families | Health service contacts for asthma by number of cigarettes smoked by parent per day (compared to 0–5) | 6-10 | IRR 0.81, 95% CI 0.71-0.92 | 0.0002 for trend |
438 children | 11-15 | IRR 0.70, 95% CI 0.59-0.83 | |||
16-20 | IRR 0.74, 95% CI 0.61-0.91 | ||||
>20 | IRR 0.66, 95% CI 0.47-0.93 | ||||
Birth weight
| |||||
Ward et al. 2007[30] | 16,756 parents | Mean birth weight (kg) difference between SHS exposed and non-exposed non smoking mothers | crude | NR | <0.001 |
adjusted | 0.025 | ||||
Bone Characteristics
| |||||
Macdonald Wallis et al. 2011[31] | 3591 | TBLH bone area in girls at age 10 by paternal smoking during pregnancy vs. no smoking | NA | 0.029 (fully adjusted analysis) | |
Breast Cancer
| |||||
Roddam et al. 2007[32] | 640 controls, 639 cases | Breast cancer in never smokers | RR 0.89, 95% CI 0.64-1.25 | NR | |
Cognitive Impairment
| |||||
Llewellyn et al. 2009[33] | 4809 | Cognitive impairment by cotinine level quartile in non-smoker (compared to lowest quartile): | |||
Second quartile cotinine level | OR 1.08, 95% CI 0.78-1.48 | 0.02 for trend | |||
Third quartile cotinine level | OR 1.13, 95% CI 0.81-1.56 | ||||
Fourth quartile cotinine level | OR 1.44, 95% CI 1.07-1.94 | ||||
Dental Caries
| |||||
Williams et al. 2000[34] | 763 | Dental caries | |||
Non-manual occupations (n = 458) | OR 1.96, 1.00–3.85 | 0.05 | |||
Manual occupations (n = 280) | OR 1.55, 1.02–2.35 | <0.05 | |||
Meningitis Carriage and Disease
| |||||
MacLennan et al. 2006[35] | 13,919 | Meningococcal carriage in exposed (n = 5064) | OR 1.17, 95% CI 1.05-1.30 | 0.004 | |
vs. non-exposed (n = 8547) | |||||
Coen 2006[36] | 144 survivors | Meningococcal disease in adolescents exposed to smokers | OR 1.83; 95% CI 1.0–3.3 | 0.01 | |
144 matched controls |
Asthma and respiratory symptoms
Birth outcomes
Bone characteristics
Breast cancer
Cognitive impairment
Dental caries
Meningitis carriage and disease
The impact of secondhand smoke exposure on smoking behaviour
Summary of relevant studies
Impact on smoking behaviour
Study ID | Behaviour outcome | N | OR for exposure compared to non-exposure | P value |
---|---|---|---|---|
Milton et al. 2004[37] | Ever tried smoking: | |||
Currently exposed to smokers in the home vs. | 254 at aged 10 | NR | <0.001 | |
non-smokers | 238 at aged 11 | <0.001 | ||
Currently exposed to SHS in the home vs. not | 256 at aged 10 | NR | 0.136 (aged 10) | |
exposed | 236 at aged 11 | 0.064 (aged 11) | ||
Tried smoking by age 11: | ||||
Exposed to smoking father at age 9 | NR | OR 5.27, 95% CI 2.18 – 12.74 | 0.002 | |
vs. non-smoking father | ||||
Exposed to smoking brother at age 9 | NR | OR 5.32, 95% CI 1.36 – 21.18 | 0.017 | |
vs. non-smoking brother | ||||
Griesbach et al. 2003[38] | Being a daily smoker by the presence of either one or both parents who smoke | |||
Scotland | 1635 | OR 1.73, 95% CI 1.32-2.26 | <0.001 | |
Wales | 1364 | OR 1.98, 95% CI 1.46-2.70 | <0.001 | |
Being a daily smoker by the presence of other (non-parent) smoker at home | ||||
Scotland | 1635 | OR 2.43, 95% CI 1.84-3.22 | <0.001 | |
Wales | 1364 | OR 2.11, 95% CI 1.47-3.02 | <0.001 |