Dietary assessment and prevention of hypertension in Nigeria: Protocol for a retrospective cross-sectional study for the development and validation of a food frequency questionnaire for clinical use.

Contrary to North America and Europe, the prevalence of hypertension is rising in West Africa. With a transition from whole foods to processed foods in Nigeria, diet plays a key driver of hypertension. To combat this, the national nutritional guidelines in Nigeria were implemented, but their translation into actionable tools for clinicians remains a challenge. Currently, there are no simple dietary assessment tools that are concise and suitable to be incorporated into clinical care without requiring extensive data analysis while still providing personalised dietary support to their patients. This study aims to deliver a clinically tested and validated short dietary assessment tool for clinicians, patients, and researchers across Nigeria to provide personalised dietary advice for patients with hypertension. The study will be conducted in two phases: Phase 1 (n = 75) will investigate the feasibility of the short FFQ and its agreement with 24-hour dietary recalls (3x) in a clinical setting in Nigeria. During the analysis of Phase 1 data, a scoring system will be developed based on the associations between individual food items in the FFQ and measures of hypertension. Phase 2 (n = 50) will assess the acceptability of the FFQ and validate the association between the FFQ score and hypertension. Expected outcomes: The development of a clinically tested and validated short food frequency questionnaire that will be ready to use by clinicians, patients, and researchers across Nigeria to support the prevention and management of hypertension. This study will contribute to knowledge on dietary assessment and hypertension prevention by developing a validated and acceptable FFQ, which will be valuable for clinicians and researchers for personalised dietary recommendations to combat hypertension in Nigeria.