Colorectal Cancer Risk Factors in Adults in Nigeria

Area of Science:

• Oncology
• Epidemiology
• Public Health

Background:

• Colorectal cancer (CRC) incidence is rising in sub-Saharan Africa, particularly Nigeria, with high mortality due to late diagnosis.
• Limited screening access necessitates identifying specific risk factors relevant to the Nigerian population.
• Existing data on CRC risk factors primarily comes from high-income countries, with applicability to Nigeria being uncertain.

Purpose of the Study:

• To investigate the association between 13 established CRC risk factors from high-income populations and CRC in Nigerian adults.
• To determine if known CRC risk factors are applicable to the Nigerian demographic, which may have unique characteristics.

Main Methods:

• A multicenter case-control study involving 2063 participants (1103 males) across 6 hospitals in Nigeria.
• Participants included newly diagnosed CRC patients and cancer-free controls matched for age, sex, location, education, and recruitment site.
• Associations were analyzed using multivariable unconditional logistic regression, calculating odds ratios (ORs) and 95% confidence intervals (CIs).

Main Results:

• Family history of cancer (OR, 1.55), adult height (OR per 5cm, 1.09), larger body size over life course (OR, 1.88), and higher processed meat intake (OR, 1.43) were associated with increased CRC risk.
• Physical activity demonstrated an inverse U-shaped association with CRC risk (e.g., OR for quartile 2 vs 1, 0.63).
• Body Mass Index (BMI) showed an inverse association (OR for BMI <18.5 vs 18.5-24.9, 2.63), potentially due to prediagnostic weight loss; no significant associations were found for diabetes, smoking, red meat, fruit, vegetable, fiber, or alcohol intake.

Conclusions:

• CRC risk factor patterns in Nigerian adults are largely consistent with those observed in high-income populations.
• These findings support tailoring public health strategies for CRC education, prevention, and early detection in Nigeria.
• The study provides a basis for future research on CRC in African populations and highlights the need for culturally relevant interventions as lifestyles evolve.