Overweight and obesity as risk factors for cervical cancer and detection of precancers among screened women: A nationwide, population-based cohort study

OBJECTIVE: Obesity is a known risk factor for many types of cancer. However, there is no clear evidence whether overweight and obesity increases the risk of cervical cancer. We investigated the association between body mass index (BMI) and detection of squamous and glandular cervical cancer and precancer.

METHODS: Based on the Medical Birth Registry, we conducted a nationwide cohort study in Denmark of 384,559 women with BMI ≥18.5 kg/m2 (pre-pregnancy BMI reported at the start of the pregnancy) having a cervical cytology screening at age 23-49 years within 5 years following the date of childbirth. The cohort was followed for 10 years from the first cervical cytology screening after the childbirth. We assessed absolute risks of cervical lesions according to BMI with the Aalen-Johansen estimator. We conducted Cox proportional hazards regression analyses to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). Analyses were adjusted for age, calendar year, parity, oral contraception use, HPV vaccination, smoking, country of origin, and education.

RESULTS: Overweight and obesity were associated with higher rates of cervical cancer (HR = 1.24, 95% CI 1.04-1.49 and HR = 1.14, 95% CI 0.91-1.43, respectively) and lower rates of cervical precancer detection (HR = 0.88, 95% CI 0.84-0.92 and HR = 0.67, 95% CI 0.63-0.71, respectively).

CONCLUSIONS: Higher than normal BMI was associated with higher incidence rates of cervical cancer and lower rates of precancer detection, emphasizing the importance of further research in possible mechanisms behind this association.