Table 1 Results and main conclusions relating to identified risk factors from included studies: risk of contraction
From: The impact of behavioural risk factors on communicable diseases: a systematic review of reviews
Disease contracted | Ref | Definition of risk factor | Meta-analysis findings | No. of studiesa | Conclusionb | |
|---|---|---|---|---|---|---|
Comparison group | Effect size (95% CI) | Effect direction | ||||
Alcohol as a risk factor | ||||||
 TB | [18] | Any alcohol use or higher amounts | No alcohol or lower amounts | OR 1.90 (1.63–2.23) | 44 | ↑ |
[19] | Alcohol consumption | N/A | Unclear | – | ||
 HIV | [20] | Binge drinking or alcohol misuse | N/A | 2 | ↑ | |
 Pneumonia | [21] | Any alcohol use or higher amounts | No alcohol or lower amounts | RR 1.83 (1.30–2.57) | 14 | ↑ |
[22] | AUD | No AUD | RR 8.22 (4.85–13.95) | 2 | ↑ | |
 IBD (IPD) | [23] | Alcohol consumption | N/A | 6 | ↑ | |
Illicit drug use as a risk factor | ||||||
 TB | [19] | Drug abuse | – | Unclear | – | |
[24] | Injection drug use | – | Unclear | ↑ | ||
 HIV | [20] | Injecting drugs, smoking crack cocaine | – | 7 | ↑ | |
[25] | Illicit drug use | – | 7 | ↑ | ||
[24] | Injection drug use | – | Unclear | ↑ | ||
 HCV | [26] | PWID | Community based studies and blood donors | Prevalence of HCV: |  | ↑ |
PWID 44.71% (37.5–52.03) | 46 | |||||
Community 0.85% (0.00–3.98) | 4 | |||||
Blood donors 0.44% (0.40–0.49) | 211 | |||||
[27] | PWID | General population | Prevalence of HCV: |  | ↑ | |
PWID 52.2% (46.9–57.5) | 56 | |||||
General pop. 0.3% (0.2–0.4) | 122 | |||||
[28] | PWID | General population | Prevalence of HCV: |  | ↑ | |
PWID 53.6% (36.2–70.6) | 15 | |||||
General pop. 6.2% (5.7–6.7) | 148 | |||||
[29] | PWID | – | 7 | ↑ | ||
Obesity as a risk factor | ||||||
 Influenza | [30] | Obesity and morbid obesity | – | 7 | ↑ | |
 Pneumonia | [31] | Obesity (BMI: 30–39.9 kg/m2) | Normal weight | CAP: RR 1.03 (CI 0.8–1.3) | 10 | ↑ |
Influenza related: RR 1.31 (1.05–1.63) | 10 | |||||
Nosocomial: RR 1.26 (0.80–1.98) | 5 | |||||
[32] | Overweight and obesity | Normal weight | RR 1.33 (95% CI 1.04–1.71) | 13 | ↑ | |
Smoking as a risk factor | ||||||
 HIV | [20] | Current smoking | – | 1 | ↑ | |
 Pneumonia | [33] | a) Current smoking | Never smokers | a) OR 2.17 (1.70–2.76) | 13 | ↑ |
b) Ever smoked |  | b) OR 2.31 (1.99–2.69) | 13 | |||
 IBD (IPD) | [23] | Current or former smoking | – | 6 | ↑ | |
Second-hand smoke as a risk factor | ||||||
 TB | [34] | Exposure to ETS | No exposure to ETS | TB infection (children): OR 1.9 (0.9–2.9) | 3 | ↑ |
TB disease (children): OR 2.8 (0.9–4.8) | 5 | |||||
[35] | Exposure to SHS | No exposure to SHS | TB infection (children): RR 1.19 (0.90–1.57) | 6 | ↑— | |
TB disease: RR 1.59 (1.11–2.27) | 6 | |||||
[36] | Exposure to SHS | No exposure to SHS | TB infection: RR 1.67 (1.12–2.48) and adjusting for age/SES, RR 1.11 (0.90–1.57) | 6 | – | |
TB disease: RR 1.96 (1.37–2.80) and adjusting for age/SES, RR 2.13 (1.18–3.83) | 12 | |||||
 Pneumonia | [33] | Exposure to ECS | No exposure to ECS | Aged 65+: OR 1.64 (1.17–2.30) | 2 | ↑— |
All ages: OR 1.13 (0.94–1.36) | 5 | |||||
 IBD | [37] | Exposure to SHS | No exposure to SHS | IMD: OR 2.02 (1.52–2.69) | 16 | ↑— |
IHD: OR 1.22 (0.93–1.62) and | 12 | |||||
IHD (pre-schoolers) OR 1.46 (1.19–1.81) | 9 | |||||
IPD: OR 1.21 (0.69–2.14) | 4 | |||||
Physical inactivity as a risk factor | ||||||
 Influenza Pneumonia | [38] | Lack of prolonged, moderate aerobic exercise | – | 7 | ↑ | |