An Original Epidemiological and Radiological Investigation of Ionising Radiation-Associated Health Effects in Occupationally Exposed Radiology Workers in Nigeria

The long-term health effects of occupational ionising radiation exposure in Nigerian radiology workers are unknown because no systematic epidemiological study has been conducted in this population, despite decades of cumulative dose accumulation among a substantial registered workforce and documented deficiencies in occupational dose monitoring practices. This study conducts an original epidemiological and radiological investigation of radiation-associated health effects in occupationally exposed radiology workers in Nigeria. A retrospective cohort study design follows 1,200 Nigerian Radiographers Registration Board members with at least ten years of occupational exposure from 2010 to 2023, compared to an age and sex-matched reference cohort of 1,200 non-radiation healthcare workers. Phase one reconstructs individual cumulative dose estimates from NNRA dosimetry records, employment histories, and Monte Carlo workplace exposure modelling for workers with incomplete monitoring records. Phase two conducts health outcome assessment including ophthalmological examination for lens opacity using standardised LOCS III grading, thyroid ultrasound for nodule assessment, haematological indices including complete blood count and chromosomal aberration frequency, and skin examination for radiation dermatitis. Poisson regression in STATA evaluates the dose-response relationship between cumulative dose and each health outcome, controlling for confounders. Available radiography occupational health literature from Nigeria identifies the absolute absence of cohort-based health outcome data as the primary evidence gap. The ICRP dose-response model for occupational stochastic effects and the epidemiological methods of the IARC occupational radiation studies provide the analytical reference. Findings will generate the first Nigerian occupational radiation dose-effect evidence. Keywords: occupational radiation exposure, health effects, radiography workers, epidemiological study, Nigeria.