Validation of Age Determination with Historical Events in Birnin Kebbi, Northwest Nigeria.

Context: Birth registration is not universal and remains elusive for some people living in developing countries, such as Nigeria; hence, age determination for healthcare and health-related research is often problematic.

Aims: The aim is to validate the use of a historical events' scale as a tool for estimating the age of Nigerian adults residing in Birnin Kebbi, Northwest Nigeria.

Settings and design: A cross-sectional survey was conducted in Birnin Kebbi, a metropolitan capital city of Kebbi state, Northwest Nigeria, and included adults aged 18 years and older with a valid document indicating their year of birth.

Subjects and methods: Seven historical events comprising major national events were cross-referenced to the individual's personal history to estimate their ages, which were then compared to their documented ages.

Statistical analysis used: Relationship of the documented and estimated ages was assessed with the Spearman's rank-order correlation and intraclass correlation coefficient (ICC) analyses.

Results: A total of 288 subjects (63.2% males) with a mean documented age of 34.5 ± 11.3 (range 18-75) years were surveyed. The mean estimated age was 32.5 ± 11.18 years. Spearman's rank-order correlation analysis showed a statistically strong positive correlation between the actual and estimated ages (0.953, P < 0.001). The ICC between documented and estimated ages was 0.968 (95% confidence interval = 0.959-0.975).

Conclusions: The use of this tool in Nigerian adults provides a reasonably accurate age estimation. Its use in populations and communities with inadequate birth registration may improve the quality of age-related health data in Nigerian adults.