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Cervical cancer risk factors

The key risk factors for cervical cancer are discussed on this page. Cervical cancer risk is also strongly linked with age.

An estimated 100% of cervical cancer cases in the UK are linked to lifestyle,1 because almost all cases are a result of human papillomavirus (HPV) infection.2  

The role of other risk factors in cervical cancer development is generally limited to modifying risk of becoming infected with HPV, and/or risk of HPV infection developing into cervical cancer.

Meta-analyses and systematic reviews are cited where available, as they provide the best overview of all available research and most take study quality into account. Individual case-control and cohort studies are reported where such aggregated data are lacking.

Cervical cancer risk factors overview

The International Agency for Research on Cancer (IARC) evaluates evidence on the carcinogenic risk to humans of a number of exposures including tobacco, alcohol, infections, radiation, occupational exposures, and medications.3,4 The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) evaluates evidence for other exposures including diet, overweight and obesity, and physical exercise.5 IARC and WCRF/AICR evaluations are the gold standard in cancer epidemiology. Their conclusions about cervical cancer risk factors are shown in Table 4.1. The WCRF/AICR evaluation for cervical cancer concludes that food and nutrition and associated factors are not significant factors in modifying cervical cancer risk, although general nutritional status may affect a woman’s vulnerability to infection.5

Table 4.1: IARC and WCRF/AICR Evaluations of Cervical Cancer Risk Factors

Increases risk ('sufficient' or 'convincing' evidence) May increase risk ('limited' or 'probable' evidence) Decreases risk ('sufficient' or 'convincing' evidence) May decrease risk ('limited' or 'probable' evidence)
  • Human papillomavirus (HPV) types 16,18, 31, 33, 35, 39, 45, 51, 52, 56, 58,59
  • Human immunodeficiency virus (HIV)
  • Oestrogen-progestogen contraceptives
  • Diethylstilbestrol (in utero exposure)a
  • Tobacco smoking
  • Human papillomavirus types 26, 53, 66, 67, 68, 70, 73, 82
  • Tetrachloroethylene

-

  • Carrots
a IARC classifies in utero diethylstilbestrol exposure as a cause of cervical adenocarcinoma; and as a probable cause of cervical squamous cell carcinoma, based on limited evidence.


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Age

Cervical cancer risk is strongly related to age, with higher incidence in younger women.

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Human papillomavirus (HPV)

HPV infection

Human papillomavirus (HPV) types 16,18, 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59 are classified by IARC as causes of cervical cancer, and HPV types 26, 53, 66, 67, 68, 70, 73, and 82 are classified as probable causes of cervical cancer, based on limited evidence (Table 4.1).3 All cervical cancers in the UK are linked to HPV, because HPV is a necessary cause of cervical cancer;1,2 however some HPV types are high-risk for cervical cancer, others are low-risk.

HPV infection is common, but progresses to cervical cancer in a minority of cases.6  Around 12% of women without cervical abnormalities in the UK and Ireland are infected with high-risk HPV types, a meta-analysis has shown.7 The highest prevalence is in younger women.7 Around half of HPV infections clear within 6-12 months, though high-risk HPV types persist longer than low-risk types, a meta-analysis showed.8

Fewer than 10% of persistent HPV infections progress to carcinoma in situ,8 which left untreated, can progress to cervical cancer.6

HPV16 and HPV18 account for 58% and 16% respectively of all cervical cancer cases in Europe, a pooled analysis showed.9 These types are protected against by the UK HPV vaccination programme.

Cervical cancer risk is not associated with infection with low-risk HPV types, cohort studies have shown.10,11 Cervical cancer risk is higher in women with genital warts (GW) versus those without, a cohort study showed;12 though GW are usually caused by low-risk HPV types (6 and 11), co-infection with high-risk HPV types is likely.12

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HPV exposure

Other factors may be associated with cervical cancer risk because they increase the risk of HPV exposure or persistent HPV infection (and/or may have direct effects, independent of HPV).4

Cervical cancer risk is almost three times higher in women who have had 6 or more sexual partners, compared with those who have had only one, a pooled analysis showed.13 Cervical cancer risk is around doubled in women who first had sexual intercourse aged 14 or younger, compared with those who did so aged 25 or older, a pooled analysis showed.13

Cervical cancer risk is around halved in women whose only current male sexual partner is circumcised, compared with those whose partner is uncircumcised, a pooled analysis showed;14 HPV prevalence is lower in circumcised versus uncircumcised men, a meta-analysis showed.15

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Other infections

Human immunodeficiency virus (HIV)

Human immunodeficiency virus (HIV) is classified by IARC as a cause of cervical cancer (Table 4.1).3

Cervical cancer risk is 6 times higher in women with HIV/AIDS, versus women in the general population, a meta-analysis showed.16 Cervical cancer risk among women with HIV may be reduced by treatment with highly active antiretroviral therapy (HAART), perhaps because HAART improves immune function to support HPV clearance.17-20

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Other sexually transmitted infections (STIs)

Cervical cancer risk may be further increased in women with other sexually transmitted infections (STIs) alongside HPV, a cohort study indicates.21 This may reflect inhibited ability to clear HPV infection due to immune suppression by other STIs. Failure to detect and treat pre-cancerous lesions in women with STIs may not explain the association, as women with a history of STIs may be more likely to attend cervical screening, versus women without such a history, a cohort study showed.22

Cervical cancer risk may be higher in those with herpes simplex virus 2, versus those without this infection, studies have shown.23-26

Cervical cancer risk in HPV-positive women is higher in those with Chlamydia trachomatis (CT), versus those without this infection.26-28 Cervical adenocarcinoma risk is not associated with CT infection, a pooled case-control study showed.29

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Reproductive and hormonal factors

Oral contraceptives (OCs) 

Use of oestrogen-progestagen contraceptives (usually oral contraceptives,OCs) is classified by IARC as a cause of cervical cancer (Table 4.1).3 An estimated 10% of cervical cancers in the UK are linked to use of OCs.30

Cervical cancer risk is up to doubled in current OC users who have used OCs for 5+ years, compared with never users, pooled- and meta-analyses have shown.31-33 Cervical cancer risk may increase with longer duration of use,31,32 but is no higher in women who last took OCs 10+ years ago, compared with never-users.31

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Parity

Cervical cancer risk is 15% higher in women who have had 1 full-term pregnancy compared with those who have had none, a pooled analysis showed; the risk increases with number of full-term pregnancies.34 Cervical cancer risk among parous women is 64% higher in those with 7+ full-term pregnancies, versus those with 1 or 2, this pooled analysis showed.34 The association with parity is limited to squamous cell carcinoma, with no association for adenocarcinoma, this pooled analysis showed.34The reasons for these associations are unknown.

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Age at first full-term pregnancy

Cervical cancer risk among parous women is 77% higher in those under 17 years old at their first full-term pregnancy, compared with those aged 25 or older, a pooled analysis has shown; the risk decreases with older age at first full-term pregnancy.34 The association with age at first full-term pregnancy is limited to squamous cell carcinoma, with no association for adenocarcinoma, this pooled analysis showed.34

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Tobacco

Smoking

Tobacco smoking is classified by IARC as a cause of cervical cancer (Table 4.1).3  An estimated 7% of cervical cancers in the UK are linked to tobacco smoking.1

Cervical squamous cell carcinoma risk is 1.5 times higher in current smokers versus never-smokers, a pooled analysis showed.35 Cervical squamous cell carcinoma (invasive or in situ) risk increases with number of cigarettes smoked per day, a pooled analysis showed.35

Cervical squamous cell carcinoma risk is not associated with past smoking, only current smoking, a pooled analysis showed.35 Carcinoma in situ risk is 83% higher in current smokers, and 32% higher in past smokers, versus never-smokers, a pooled analysis showed.35

Cervical adenocarcinoma risk is not associated with smoking, a pooled analysis showed.35

Cervical cancer risk may be higher in current smokers because they are more likely to have HPV infection (more likely to contract HPV, less able to clear HPV, or both),36 or because smoking causes cancerous progression in HPV-infected cells.35

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Environmental tobacco smoke

Cervical cancer risk is 73% higher in never-smoking women exposed to environmental tobacco smoke, compared with those who are not exposed, a meta-analysis showed.37

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Occupational exposures

Tetrachloroethylene is classified by IARC as a cause of cervical cancer, based on limited evidence (Table 4.1).3 An estimated 0.7% of cervical cancers in the UK are linked to tetrachloroethylene exposure.1

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Previous cancer

Cervical cancer develops in under 1% of young women with carcinoma in situ per year.38 Cervical cancer risk is higher in survivors of vaginal and vulval, kidney, urinary tract, or skin cancers, cohort studies have shown.39,40Bidirectional associations between risk of cervical cancer and risk of other HPV-related cancer types, and cancers at sites near to the cervix, indicate shared causal factors and the effect of radiotherapy treatment.41

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Family history and genetic conditions

Family history

Cervical squamous cell carcinoma risk is 74-80% higher in women with a first-degree relative (mother, sister, daughter) with cervical squamous cell carcinoma, compared with the general population, a cohort study showed.42 Cervical adenocarcinoma risk is 39-69% higher in women with a first-degree relative with cervical squamous cell carcinoma, compared with the general population, a cohort study showed42

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Medical conditions and treatments

Diethylstilboestrol (DES) exposure in utero is classified by IARC as a cause of cervical adenocarcinoma; it is classified as a probable cause of cervical squamous cell carcinoma, based on limited evidence (Table 4.1).3

Cervical cancer and high-grade carcinoma in situ risk is 2.3 times higher in women who were exposed in utero to DES, a cohort study showed.43

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Immune system

Cervical dysplasia risk is higher in women with the autoimmune diseases systemic lupus erythematosus or rheumatoid arthritis, a meta-analysis and cohort study have shown.44,45 Use of immunosuppressant drugs in these conditions may inhibit HPV clearance.

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Factors shown to decrease or have no effect on cervical cancer risk

Decrease

Carrots are classified by WCRF/AICR as probably protective against cervical cancer, based on limited evidence (Table 4.1).5
Cervical cancer risk is 40-49% lower in women with the highest dietary vitamin A, carotene and other carotenoids intake versus those with the lowest, a meta-analysis showed.46Carotenoids are found at high levels in carrots; some are precursors of vitamin A but also have independent antioxidant properties

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Cervical cancer risk is 45% lower in women who have ever used an intrauterine device (IUD), versus never-users, a meta-analysis showed; IUD use may reduce risk of HPV progression to cervical cancer.47

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No effect

WCRF/AICR concludes that food and nutrition and associated factors are not significant factors in modifying cervical cancer risk.5

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Cervical cancer risk is not associated with the following factors, meta- and pooled analyses or systematic reviews have shown:

  • Physical activity48 (though some evidence of risk decrease49).
  • Overweight and obesity (though some evidence of risk increase,49  perhaps due to lower cervical screening attendance in larger women50 ).
  • Postmenopausal hormone replacement therapy.51
  • Organ transplant receipt52 ,53  (some evidence of risk increase, this variation may reflect differing use of cervical screening in the transplant population over time/between countries16,54).
  • Non-steroidal anti-inflammatory drugs (NSAIDs)  use55 (also no effect on risk of progression from carcinoma in situ to cancer56 ).
  • Statins.57  
  • Undergoing in vitro fertilisation (IVF).58

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References for cervical cancer risk factors

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Updated: 18 August 2014