Blood biomarkers of trans-fatty acid intake among Nigerian adults in the Federal Capital Territory: a cross-sectional study.

Background: Intake of trans-fatty acids (TFAs) is an established risk factor for cardiovascular disease. In April 2023, Nigeria passed regulations limiting TFA content in foods, fats, and oils, but the current level of TFA exposure in the Nigerian population is unknown.

Objectives: To quantify trans-fatty acid (TFA) biomarkers in dried blood spots from Nigerian adults in the Federal Capital Territory before policy enforcement, establish baseline levels for future evaluations, assess subgroup variations by demographic and socioeconomic factors, and compare TFA levels with data from 30 countries worldwide.

Methods: We used gas chromatography to measure TFA content in dried blood spots from adults participating in a cross-sectional household survey using a representative sampling frame. Individual TFA (t-16:1, t-18:1, and t- 18:2) and their total were expressed as percentage of total fatty acids. We assessed differences in TFA levels between subgroups based on sex, age, body mass index (BMI), education, income, and local government area using multivariable-adjusted linear regression models. Mean TFA levels were compared with samples from individuals in 30 countries.

Results: In 213 adults (62% females; mean age: 36 y, mean BMI: 25.9 kg/m), the mean TFA level in dried blood spots was 0.61% of total fatty acids (range: 0.23%-1.31%). In multivariable-adjusted models, TFA levels were higher in younger adults {<30 y compared with ≥42 y, 0.07% [95% confidence interval (CI): 0.00, 0.15], P = 0.047}, those without a high school degree [compared with higher education, 0.08% (95% CI: 0.01, 0.16), P = 0.023], and residents of Abuja Municipal Area Council [compared with residents in Gwagwalada, 0.12% (95% CI: 0.05, 0.20), P = 0.001]. Total TFA levels were comparable with international samples, but t-16:1 and t-18:1 appeared lower, whereas t-18:2 appeared greater (52% of all TFA), in the Nigerian samples.

Conclusions: These results provide a baseline assessment of TFA exposure in Nigerian adults to evaluate implementation and effect of national regulation passed in 2023. The observed subgroup differences may help identify subpopulations for targeted interventions to reduce TFA intake.